10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

þ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2012.

or

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                  to                 

Commission File Number 1-10709

PS BUSINESS PARKS, INC.

(Exact name of registrant as specified in its charter)

California	95-4300881
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

701 Western Avenue, Glendale, California 91201-2397

(Address of principal executive offices) (Zip Code)

818-244-8080

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class	Name of Each Exchange on Which Registered
Common Stock, $0.01 par value per share	New York Stock Exchange
Depositary Shares Each Representing 1/1,000 of a Share of 6.875% Cumulative Preferred Stock, Series R, $0.01 par value per share	New York Stock Exchange
Depositary Shares Each Representing 1/1,000 of a Share of 6.450% Cumulative Preferred Stock, Series S, $0.01 par value per share	New York Stock Exchange
Depositary Shares Each Representing 1/1,000 of a Share of 6.000% Cumulative Preferred Stock, Series T, $0.01 par value per share	New York Stock Exchange
Depositary Shares Each Representing 1/1,000 of a Share of 5.750% Cumulative Preferred Stock, Series U, $0.01 par value per share	New York Stock Exchange

Securities registered pursuant to Section 12(g) of the Act:

None

(Title of class)

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  þ    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ¨    No  þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.    Yes  þ    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  þ    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§232.405) is not contained herein, and will not be contained, to the best of the registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    þ

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer þ	Accelerated filer ¨
Non-accelerated filer ¨	Smaller reporting company ¨
(Do not check if a smaller reporting company)

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  þ

As of June 30, 2012, the aggregate market value of the registrant’s common stock held by non-affiliates of the registrant was $1,229,654,681 based on the closing price as reported on that date.

Number of shares of the registrant’s common stock, par value $0.01 per share, outstanding as of February 18, 2013 (the latest practicable date): 24,298,475.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the definitive proxy statement to be filed in connection with the Annual Meeting of Shareholders to be held in 2013 are incorporated by reference into Part III of this Annual Report on Form 10-K.

PART I

ITEM 1. BUSINESS

Forward-Looking Statements

Forward-looking statements are made throughout this Annual Report on Form 10-K. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, the words “may,” “believes,” “anticipates,” “plans,” “expects,” “seeks,” “estimates,” “intends,” and similar expressions are intended to identify forward-looking statements. There are a number of important factors that could cause the results of the Company to differ materially from those indicated by such forward-looking statements, including but not limited to: (a) changes in general economic and business conditions; (b) decreases in rental rates or increases in vacancy rates/failure to renew or replace expiring leases; (c) tenant defaults; (d) the effect of the recent credit and financial market conditions; (e) our failure to maintain our status as a REIT; (f) the economic health of our tenants; (g) increases in operating costs; (h) casualties to our properties not covered by insurance; (i) the availability and cost of capital; (j) increases in interest rates and its effect on our stock price; (k) other factors discussed under the heading “Item 1A. Risk Factors”. In light of the significant uncertainties inherent in the forward-looking statements included herein, the inclusion of such information should not be regarded as a representation by us or any other person that our objectives and plans will be achieved. Moreover, we assume no obligation to update these forward-looking statements to reflect actual results, changes in assumptions or changes in other factors affecting such forward-looking statements, except as required by law.

The Company

PS Business Parks, Inc. (“PSB”) is a fully-integrated, self-advised and self-managed real estate investment trust (“REIT”) that owns, operates, acquires and develops commercial properties, primarily multi-tenant flex, office and industrial parks. PS Business Parks, L.P. (the “Operating Partnership”) is a California limited partnership, which owns directly or indirectly substantially all of our assets and through which we conduct substantially all of our business. PSB is the sole general partner of the Operating Partnership and, as of December 31, 2012, owned 76.9% of the common partnership units. The remaining common partnership units are owned by Public Storage (“PS”). PSB, as the sole general partner of the Operating Partnership, has full, exclusive and complete responsibility and discretion in managing and controlling the Operating Partnership. Unless otherwise indicated or unless the context requires otherwise, all references to “the Company,” “we,” “us,” “our,” and similar references mean PS Business Parks, Inc. and its subsidiaries, including the Operating Partnership.

As of December 31, 2012, the Company owned and operated 28.3 million rentable square feet of commercial space, comprising 102 business parks, located in eight states: Arizona, California, Florida, Maryland, Oregon, Texas, Virginia and Washington. The Company focuses on owning concentrated business parks which provide the Company with the greatest flexibility to meet the needs of its customers. The Company also manages 1.2 million rentable square feet on behalf of PS.

History of the Company: The Company was formed in 1990 as a California corporation under the name Public Storage Properties XI, Inc. In a March 17, 1998 merger with American Office Park Properties, Inc. (“AOPP”) (the “Merger”), the Company acquired the commercial property business operated by AOPP and was renamed “PS Business Parks, Inc.” Prior to the Merger, in January, 1997, AOPP was reorganized to succeed to the commercial property business of PS, becoming a fully integrated, self-advised and self-managed REIT.

2

From January, 2010 through December, 2012, the Company has acquired 9.1 million square feet of multi-tenant flex, office and industrial parks for an aggregate purchase price of $907.6 million. The table below reflects the assets acquired during this period (in thousands):

Property	Date Acquired		Location		Purchase Price		Square Feet		Occupancy at December 31, 2012
Austin Flex Buildings		December, 2012		Austin, Texas	$	14,900		226		86.1	%
212th Business Park		July, 2012		Kent Valley, Washington		37,550		958		50.7	%
Total 2012 Acquisitions					$	52,450		1,184		57.4	%
Northern California Portfolio		December, 2011		East Bay, California	$	520,000		5,334		86.3	%
Royal Tech		October, 2011		Las Colinas, Texas		2,835		80		100.0	%
MICC — Center 22		August, 2011		Miami, Florida		3,525		46		33.3	%
Warren Building		June, 2011		Tysons Corner, Virginia		27,100		140		88.2	%
Total 2011 Acquisitions					$	553,460		5,600		86.1	%
Westpark Business Campus		December, 2010		Tysons Corner, Virginia	$	140,000		735		74.7	%
Tysons Corporate Center		July, 2010		Tysons Corner, Virginia		35,400		270		88.4	%
Parklawn Business Park		June, 2010		Rockville, Maryland		23,430		232		88.0	%
Austin Flex Portfolio		April, 2010		Austin, Texas		42,900		704		96.6	%
Shady Grove Executive Center		March, 2010		Rockville, Maryland		60,000		350		92.2	%
Total 2010 Acquisitions						301,730		2,291		87.1	%
Total					$	907,640		9,075		82.6	%

In October, 2012, the Company completed the sale of Quail Valley Business Park, a 66,000 square foot flex park in Houston, Texas, for a gross sales price of $2.3 million, resulting in a net gain of $935,000.

In August, 2011, the Company completed the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million.

In 2010, the Company completed construction of a new building within its Miami International Commerce Center (“MICC”) in Miami, Florida, which added 75,000 square feet of rentable multi-tenant industrial space. In January, 2010, the Company completed the sale of a 131,000 square foot office building located in Houston, Texas. The gross sales price was $10.0 million, resulting in a net gain of $5.2 million.

From 1998 through 2009, the Company acquired 15.8 million square feet of commercial space, developed an additional 500,000 square feet and sold 1.9 million square feet along with some parcels of land.

The Company has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with its taxable year ended December 31, 1990. To the extent that the Company continues to qualify as a REIT, it will not be taxed, with certain limited exceptions, on the net income that is currently distributed to its shareholders.

The Company’s principal executive offices are located at 701 Western Avenue, Glendale, California 91201-2397. The Company’s telephone number is (818) 244-8080. The Company maintains a website with the address www.psbusinessparks.com. The information contained on the Company’s website is not a part of, or incorporated by reference into, this Annual Report on Form 10-K. The Company makes available free of charge through its website its Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, and amendments to these reports, as soon as reasonably practicable after the Company electronically files such material with, or furnishes such material to, the Securities and Exchange Commission (the “SEC”).

Business of the Company: The Company is in the commercial property business, with 102 business parks consisting of multi-tenant flex, industrial and office space. The Company owns 14.9 million square feet of flex space. The Company defines “flex” space as buildings that are configured with a combination of warehouse and office space and can be designed to fit a wide variety of uses. The warehouse component of the flex space has a number of uses including light manufacturing and assembly, storage and warehousing, showroom, laboratory, distribution and research and development activities. The office component of flex space is complementary to the warehouse component by enabling businesses to accommodate management and production staff in the same facility. The Company owns 8.4 million square feet of industrial space that has characteristics similar to the warehouse component of the flex space as well as ample dock access. In addition, the Company owns 5.0 million square feet of low-rise office space, generally either in business parks that combine office and flex space or in submarkets where the market demand is more office focused.

3

The Company’s commercial properties typically consist of business parks with low-rise buildings, ranging from one to 48 buildings per park, located on parcels of various sizes and comprising from approximately 12,000 to 3.3 million aggregate square feet of rentable space. Facilities are managed through either on-site management or offices central to the facilities. Parking is generally open but in some instances is covered. The ratio of parking spaces to rentable square feet ranges from two to six per thousand square feet depending upon the use of the property and its location. Office space generally requires a greater parking ratio than most industrial uses. The Company may acquire properties that do not have these characteristics.

The tenant base for the Company’s facilities is diverse. The portfolio can be bifurcated into those facilities that service small to medium-sized businesses and those that service larger businesses. Approximately 34.2% of in-place rents from the portfolio are derived from facilities that serve small to medium-sized businesses. A property in this facility type is typically divided into units ranging in size from 500 to 4,999 square feet and leases generally range from one to three years. The remaining 65.8% of in-place rents from the portfolio are derived from facilities that serve larger businesses, with units greater than or equal to 5,000 square feet. The Company also has several tenants that lease space in multiple buildings and locations. The U.S. Government is the largest tenant with multiple leases encompassing approximately 870,000 square feet or 6.1% of the Company’s annualized rental income.

The Company currently owns properties in eight states and it may expand its operations to other states or reduce the number of states in which it operates. Properties are acquired for both income and potential capital appreciation; there is no limitation on the amount that can be invested in any specific property. Although there are no restrictions on our ability to expand our operations into foreign markets, we currently operate solely within the United States and have no foreign operations.

The Company owns land which may be used for the development of commercial properties. The Company owns approximately 6.4 acres of such land in Northern Virginia, 11.5 acres in Portland, Oregon and 10.0 acres in Dallas, Texas as of December 31, 2012.

Operating Partnership

The properties in which the Company has an equity interest generally are owned by the Operating Partnership. Through this organizational structure, the Company has the ability to acquire interests in additional properties in transactions that could defer the contributors’ tax consequences by causing the Operating Partnership to issue equity interests in return for interests in properties.

The Company is the sole general partner of the Operating Partnership. As of December 31, 2012, the Company owned 76.9% of the common partnership units of the Operating Partnership, and the remainder of such common partnership units were owned by PS. The common units owned by PS may be redeemed by PS from time to time, subject to the provisions of our charter, for cash or, at our option, shares of our common stock on a one-for-one basis. Also as of December 31, 2012, in connection with the Company’s issuance of publicly traded Cumulative Preferred Stock, the Company owned 35.4 million preferred units of the Operating Partnership of various series with an aggregate redemption value of $885.0 million with terms substantially identical to the terms of the publicly traded depositary shares each representing 1/1,000 of a share of 5.750% to 6.875% Cumulative Preferred Stock of the Company.

As the general partner of the Operating Partnership, the Company has the exclusive responsibility under the Operating Partnership Agreement to manage and conduct the business of the Operating Partnership. The Board of Directors directs the affairs of the Operating Partnership by managing the Company’s affairs. The Operating Partnership is responsible for, and pays when due, its share of all administrative and operating expenses of the properties it owns.

4

The Company’s interest in the Operating Partnership entitles it to share in cash distributions from, and the profits and losses of, the Operating Partnership in proportion to the Company’s economic interest in the Operating Partnership (apart from tax allocations of profits and losses to take into account pre-contribution property appreciation or depreciation). The Company, since 1998, has paid per share dividends on its common and preferred stock that track, on a one-for-one basis, the amount of per unit cash distributions the Company receives from the Operating Partnership in respect of the common and preferred partnership units in the Operating Partnership that are owned by the Company.

Cost Allocation and Administrative Services

Pursuant to a cost sharing and administrative services agreement, the Company shares costs with PS for certain administrative services. These services include investor relations, legal, corporate tax and information systems. Under this agreement, costs are allocated to the Company in accordance with its proportionate share of these costs. These allocated costs totaled $441,000, $442,000 and $543,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

Common Officers and Directors with PS

Ronald L. Havner, Jr., Chairman of the Company, is also the Chairman of the Board, Chief Executive Officer and President of PS. Gary E. Pruitt, an independent director of the Company is also a trustee of PS. The Company engages additional executive personnel who render services exclusively for the Company. However, it is expected that certain officers of PS will continue to render services for the Company as requested pursuant to the cost sharing and administrative services agreement.

Property Management

The Company manages commercial properties owned by PS, which are generally adjacent to self-storage facilities, for a management fee of 5% of the gross revenues of such properties in addition to reimbursement of direct costs. The property management contract with PS is for a seven-year term with the agreement automatically extending for an additional one-year period upon each one-year anniversary of its commencement (unless cancelled by either party). Either party can give notice of its intent to cancel the agreement upon expiration of its current term. Management fee revenue derived from this management contract with PS totaled $649,000, $684,000 and $672,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

PS also provides property management services for the self-storage component of two assets owned by the Company. These self-storage facilities, located in Palm Beach County, Florida, operate under the “Public Storage” name. Either the Company or PS can cancel the property management contract upon 60 days’ notice. Management fee expenses under the contract were $55,000, $52,000 and $48,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

Management

Joseph D. Russell, Jr. leads the Company’s senior management team. Mr. Russell is President and Chief Executive Officer of the Company. The Company’s senior management includes: John W. Petersen, Executive Vice President and Chief Operating Officer; Edward A. Stokx, Executive Vice President and Chief Financial Officer; Maria R. Hawthorne, Executive Vice President, East Coast; Trenton A. Groves, Vice President and Corporate Controller; Coby A. Holley, Vice President (Pacific Northwest Division); Robin E. Mather, Vice President (Southern California Division); William A. McFaul, Vice President (Washington Metro Division); Ross K. Parkin, Vice President, Acquisitions and Dispositions; Eddie F. Ruiz, Vice President and Director of Facilities; Viola I. Sanchez, Vice President (Southeast Division); Richard E. Scott, Vice President (Northern California Division); Eugene Uhlman, Vice President, Construction Management; and David A. Vicars, Vice President (Midwest Division).

5

REIT Structure

If certain detailed conditions imposed by the Code and the related Treasury Regulations are met, an entity, such as the Company, that invests principally in real estate and that otherwise would be taxed as a corporation may elect to be treated as a REIT. The most important consequence to the Company of being treated as a REIT for federal income tax purposes is that the Company can deduct dividend distributions (including distributions on preferred stock) to its shareholders, thus effectively eliminating the “double taxation” (at the corporate and shareholder levels) that typically results when a corporation earns income and distributes that income to shareholders in the form of dividends.

The Company believes that it has operated, and intends to continue to operate, in such a manner as to qualify as a REIT under the Code, but no assurance can be given that it will at all times so qualify. To the extent that the Company continues to qualify as a REIT, it will not be taxed, with certain limited exceptions, on the taxable income that is distributed to its shareholders.

Operating Strategy

The Company believes its operating, acquisition and finance strategies combined with its diversified portfolio produces a low risk, stable growth business model. The Company’s primary objective is to grow shareholder value. Key elements of the Company’s growth strategy include:

Maximize Net Cash Flow of Existing Properties: The Company seeks to maximize the net cash flow generated by its properties by (i) maximizing average occupancy rates, (ii) achieving the highest possible levels of realized monthly rents per occupied square foot and (iii) controlling its operating cost structure by improving operating efficiencies and economies of scale. The Company believes that its experienced property management personnel and comprehensive systems combined with increasing economies of scale enhance the Company’s ability to meet these goals. The Company seeks to increase occupancy rates and realized monthly rents per square foot by providing its field personnel with incentives to lease space to credit tenants and to maximize the return on investment in each lease transaction. The Company seeks to maximize its cash flow by controlling capital expenditures associated with maintaining and re-leasing space by acquiring and owning properties with easily reconfigured space that appeal to a wide range of tenants.

Focus on Targeted Markets: The Company intends to continue investing in markets that have characteristics which enable them to be competitive economically. The Company believes that markets with some combination of above average population growth, job growth, higher education levels and personal income will produce better overall economic returns. The Company targets individual properties in high barrier to entry markets that are close to critical infrastructure, middle to high income housing, universities and have easy access to major transportation arteries.

Reduce Capital Expenditures and Increase Occupancy Rates by Providing Flexible Properties and Attracting a Diversified Tenant Base: By focusing on properties with easily reconfigurable space, the Company believes it can offer facilities that appeal to a wide range of potential tenants, which aids in reducing the capital expenditures associated with re-leasing space. The Company believes this property flexibility also allows it to better serve existing tenants by accommodating expansion and contraction needs. In addition, the Company believes that a diversified tenant base combined with flexible parks helps it maintain occupancy rates by enabling it to attract a greater number of potential users to its space.

Provide Superior Property Management: The Company seeks to provide a superior level of service to its tenants in order to maintain occupancy and increase rental rates, as well as minimize customer turnover. The Company’s property management offices are located on-site or regionally, providing tenants with convenient access to management and helping the Company maintain its properties and convey a sense of quality, order and security. The Company has significant experience in acquiring properties managed by others and thereafter improving tenant satisfaction, occupancy levels, renewal rates and rental income by implementing established tenant service programs.

6

Financing Strategy

The Company’s primary objective in its financing strategy is to maintain financial flexibility and a low risk capital structure. Key elements of this strategy are:

Retain Operating Cash Flow: The Company seeks to retain significant funds (after funding its distributions and capital improvements) for additional investments. During the years ended December 31, 2012 and 2011, the Company distributed 41.4% and 37.4%, respectively, of its funds from operations (“FFO”) to common shareholders/unit holders. FFO is computed in accordance with the White Paper on FFO approved by the Board of Governors of the National Association of Real Estate Investment Trusts (“NAREIT”). The White Paper defines FFO as net income, computed in accordance with U.S. generally accepted accounting principles (“GAAP”), before depreciation, amortization, gains or losses on asset dispositions, net income allocable to noncontrolling interests — common units, net income allocable to restricted stock unit holders, impairment charges and nonrecurring items. FFO is a non-GAAP financial measure and should be analyzed in conjunction with net income. However, FFO should not be viewed as a substitute for net income as a measure of operating performance as it does not reflect depreciation and amortization costs or the level of capital expenditure and leasing costs necessary to maintain the operating performance of the Company’s properties, which are significant economic costs and could materially impact the Company’s results of operations. Other REITs may use different methods for calculating FFO and, accordingly, the Company’s FFO may not be comparable to other real estate companies’ funds from operations. See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Liquidity and Capital Resources — Non-GAAP Supplemental Disclosure Measure: Funds from Operations,” for a reconciliation of FFO and net income allocable to common shareholders and for information on why the Company presents FFO.

Perpetual Preferred Stock/Units: The primary source of leverage in the Company’s capital structure is perpetual preferred stock or equivalent preferred units in the Operating Partnership. This method of financing eliminates interest rate and refinancing risks as the dividend rate is fixed and the stated value or capital contribution is not required to be repaid. In addition, the consequences of defaulting on required preferred distributions are less severe than with debt. The preferred shareholders may elect two additional directors if six quarterly distributions go unpaid, whether or not consecutive.

Throughout this Form 10-K, we use the term “preferred equity” to mean both the preferred stock issued by the Company (including the depositary shares representing interests in that preferred stock) and the preferred partnership units issued by the Operating Partnership and the term “preferred distributions” to mean dividends and distributions on the preferred stock and preferred partnership units.

Debt Financing: The Company, from time to time, has used debt financing to facilitate real estate acquisitions and other capital allocations. The primary source of debt the Company has historically relied upon to provide short-term capital is its $250.0 million unsecured line of credit (the “Credit Facility”). In addition, during 2011, in connection with its $520.0 million portfolio acquisition in Northern California, the Company obtained a $250.0 million unsecured three-year term loan and assumed a $250.0 million mortgage note.

Access to Capital: The Company targets a minimum ratio of FFO to combined fixed charges and preferred distributions paid of 3.0 to 1.0. Fixed charges include interest expense. Preferred distributions include amounts paid to preferred shareholders and preferred Operating Partnership unit holders. For the year ended December 31, 2012, the FFO to combined fixed charges and preferred distributions paid ratio was 3.1 to 1.0, excluding the charge for the issuance costs related to the redemptions of preferred equity. The Company believes that its financial position enables it to access capital to finance future growth. Subject to market conditions, the Company may add leverage to its capital structure.

Competition

Competition in the market areas in which many of the Company’s properties are located is significant and has from time to time reduced the occupancy levels and rental rates of, and increased the operating expenses of, certain of these properties. Competition may be accelerated by any increase in availability of funds for investment in real estate. Barriers to entry are relatively low for those with the necessary capital and the

7

Company competes for property acquisitions and tenants with entities that have greater financial resources than the Company. Sublease space and unleased developments are expected to continue to provide competition among operators in certain markets in which the Company operates. While the Company will have to respond to market demands, management believes that the combination of its ability to offer a variety of options within its business parks and the Company’s financial stability provide it with an opportunity to compete favorably in its markets.

The Company’s properties compete for tenants with similar properties located in its markets primarily on the basis of location, rent charged, services provided and the design and condition of improvements. The Company believes it possesses several distinguishing characteristics that enable it to compete effectively in the flex, office and industrial space markets. The Company believes its personnel are among the most experienced in these real estate markets. The Company’s facilities are part of a comprehensive system encompassing standardized procedures and integrated reporting and information networks. The Company believes that the significant operating and financial experience of its executive officers and directors combined with the Company’s capital structure, national investment scope, geographic diversity and economies of scale should enable the Company to compete effectively.

Investments in Real Estate Facilities

As of December 31, 2012, the Company owned and operated 28.3 million rentable square feet comprised of 102 business parks in eight states compared to 27.2 million rentable square feet at December 31, 2011.

Summary of Business Model

The Company has a diversified portfolio. It is diversified geographically in eight states and has a diversified customer mix by size and industry concentration. The Company believes that this diversification combined with a conservative financing strategy, focus on markets with strong demographics for growth and our operating strategy gives the Company a business model that mitigates risk and provides strong long-term growth opportunities.

Restrictions on Transactions with Affiliates

The Company’s Bylaws provide that the Company may engage in transactions with affiliates provided that a purchase or sale transaction with an affiliate is (i) approved by a majority of the Company’s independent directors and (ii) fair to the Company based on an independent appraisal or fairness opinion.

Borrowings

As of December 31, 2012, the Company had outstanding mortgage notes payable of $268.1 million compared to $282.1 million at December 31, 2011. The decrease in outstanding mortgage notes payable was due to the repayment of a $13.2 million mortgage note in November, 2012. Subsequent to December 31, 2012, the Company repaid two mortgage notes payable totaling $18.1 million. See Notes 5 and 6 to the consolidated financial statements for a summary of the Company’s outstanding borrowings as of December 31, 2012.

The Company has a line of credit (the “Credit Facility”) with Wells Fargo Bank, National Association (“Wells Fargo”) which expires on August 1, 2015. The Credit Facility has a borrowing limit of $250.0 million. The rate of interest charged on borrowings is equal to a rate ranging from the London Interbank Offered Rate (“LIBOR”) plus 1.00% to LIBOR plus 1.85% depending on the Company’s credit ratings. Currently, the Company’s rate under the Credit Facility is LIBOR plus 1.10%. In addition, the Company is required to pay an annual facility fee ranging from 0.15% to 0.45% of the borrowing limit depending on the Company’s credit ratings (currently 0.15%). The Company had no balance outstanding on the Credit Facility at December 31, 2012. The Company had $185.0 million outstanding on the Credit Facility at an interest rate of 1.41% at December 31, 2011. The Company had $791,000 and $1.1 million of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The Credit Facility requires the Company to meet certain covenants, with which the Company was in compliance at December 31, 2012 and 2011. Interest on outstanding borrowings is payable monthly.

8

In connection with the Northern California Portfolio acquisition described in Note 3, the Company entered into a term loan on December 20, 2011 with Wells Fargo, as Administrative Agent (the “Term Loan”). Pursuant to the Term Loan, the Company borrowed $250.0 million for a three year term through December 31, 2014. The maturity date of the Term Loan Agreement can be extended by one year at the Company’s election. Interest on the amounts borrowed under the Term Loan accrues based on an applicable rate ranging from LIBOR plus 1.15% to LIBOR plus 2.25% depending on the Company’s credit ratings. Currently, the Company’s rate under the Term Loan is LIBOR plus 1.20%. The Company had $200.0 million outstanding on the Term Loan at an interest rate of 1.41% at December 31, 2012 and $250.0 million outstanding at an interest rate of 1.50% at December 31, 2011. The Company had $383,000 and $729,000 of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The covenants and events of default contained in the Credit Facility are incorporated into the Term Loan by reference, and the Term Loan is cross-defaulted to the Credit Facility. The Term Loan can be repaid in full or part at any time prior to its maturity without penalty.

On February 9, 2011, the Company entered into an agreement with PS to borrow $121.0 million with a maturity date of August 9, 2011 at an interest rate of LIBOR plus 0.85%. The Company repaid, in full, the note payable to PS upon maturity.

The Company has broad powers to borrow in furtherance of the Company’s objectives. The Company has incurred in the past, and may incur in the future, both short-term and long-term indebtedness to facilitate real estate acquisitions and other capital allocations.

Employees

As of December 31, 2012, the Company employed 161 individuals, primarily personnel engaged in property operations.

Insurance

The Company believes that its properties are adequately insured. Facilities operated by the Company have historically been covered by comprehensive insurance, including fire, earthquake, liability and extended coverage from nationally recognized carriers.

Environmental Matters

Compliance with laws and regulations relating to the protection of the environment, including those regarding the discharge of material into the environment, has not had any material effect upon the capital expenditures, earnings or competitive position of the Company.

Substantially all of the Company’s properties have been subjected to Phase I environmental reviews. Such reviews have not revealed, nor is management aware of, any probable or reasonably possible environmental costs that management believes would have a material adverse effect on the Company’s business, assets or results of operations, nor is the Company aware of any potentially material environmental liability. See Item 1A, “Risk Factors” for additional information.

ITEM 1A. RISK FACTORS

In addition to the other information in our Annual Report on Form 10-K, you should consider the risks described below that we believe may be material to investors in evaluating the Company. This section contains forward-looking statements, and in considering these statements, you should refer to the qualifications and limitations on our forward-looking statements that are described in Item 1, “Business — Forward-Looking Statements.”

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Since our business consists primarily of acquiring and operating real estate, we are subject to the risks related to the ownership and operation of real estate that can adversely impact our business and financial condition.

The value of our investments may be reduced by general risks of real estate ownership: Since we derive substantially all of our income from real estate operations, we are subject to the general risks of acquiring and owning real estate-related assets, including:

• changes in the national, state and local economic climate and real estate conditions, such as oversupply of or reduced demand for commercial real estate space and changes in market rental rates;

• how prospective tenants perceive the attractiveness, convenience and safety of our properties;

• difficulties in consummating and financing acquisitions and developments on advantageous terms and the failure of acquisitions and developments to perform as expected;

• our ability to provide adequate management, maintenance and insurance;

• natural disasters, such as earthquakes, hurricanes and floods, which could exceed the aggregate limits of our insurance coverage;

• the expense of periodically renovating, repairing and re-letting spaces;

• the impact of environmental protection laws;

• compliance with federal, state, and local laws and regulations;

• increasing operating and maintenance costs, including property taxes, insurance and utilities, if these increased costs cannot be passed through to tenants;

• adverse changes in tax, real estate and zoning laws and regulations;

• increasing competition from other commercial properties in our market;

• tenant defaults and bankruptcies;

• tenants’ right to sublease space; and

• concentration of properties leased to non-rated private companies with uncertain financial strength.

Certain significant costs, such as mortgage payments, real estate taxes, insurance and maintenance, generally are not reduced even when a property’s rental income is reduced. In addition, environmental and tax laws, interest rate levels, the availability of financing and other factors may affect real estate values and property income. Furthermore, the supply of commercial space fluctuates with market conditions.

If our properties do not generate sufficient income to meet operating expenses, including any debt service, tenant improvements, lease commissions and other capital expenditures, we may have to borrow additional amounts to cover fixed costs, and we may have to reduce our distributions to shareholders.

There is significant competition among commercial properties: Many other commercial properties compete with our properties for tenants. Some of the competing properties may be newer and better located than our properties. Competition in the market areas in which many of our properties are located is significant and has affected our occupancy levels, rental rates and operating expenses. We also expect that new properties will be built in our markets. In addition, we compete with other buyers, many of which are larger than us, for attractive commercial properties. Therefore, we may not be able to grow as rapidly as we would like.

We may encounter significant delays and expense in re-letting vacant space, or we may not be able to re-let space at existing rates, in each case resulting in losses of income: When leases expire, we may incur expenses in retrofitting space and we may not be able to re-lease the space on the same terms. Certain leases provide tenants with the right to terminate early if they pay a fee. As of December 31, 2012, our properties generally had lower vacancy rates than the average for the markets in which they are located, and 2,040 leases representing 29.0% of the leased square footage of our total portfolio or 27.7% of annualized rental income are scheduled to expire in

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2013. While we have estimated our cost of renewing leases that expire in 2013, our estimates could be wrong. If we are unable to re-lease space promptly, if the terms are significantly less favorable than anticipated or if the costs are higher, we may have to reduce our distributions to shareholders.

Tenant defaults and bankruptcies may reduce our cash flow and distributions: We may have difficulty collecting from tenants in default, particularly if they declare bankruptcy. This could affect our cash flow and our ability to fund distributions to shareholders. Since many of our tenants are non-rated private companies, this risk may be enhanced. There is inherent uncertainty in a tenant’s ability to continue paying rent if they are in bankruptcy.

We may be adversely affected if casualties to our properties are not covered by insurance: We could suffer uninsured losses or losses in excess of our insurance policy limits for occurrences such as earthquakes or hurricanes that adversely affect us or even result in loss of the property. Approximately 39.4% of our properties are located in California and are generally in areas that are subject to risks of earthquake related damage. We might still remain liable on any mortgage debt or other unsatisfied obligations related to that property.

The illiquidity of our real estate investments may prevent us from adjusting our portfolio to respond to market changes: There may be delays and difficulties in selling real estate. Therefore, we cannot easily change our portfolio when economic conditions change. Also, REIT tax laws may impose negative consequences if we sell properties held for less than four years.

We may be adversely affected by changes in laws: Increases in income and service taxes may reduce our cash flow and ability to make expected distributions to our shareholders. Our properties are also subject to various federal, state and local regulatory requirements, such as state and local fire and safety codes. If we fail to comply with these requirements, governmental authorities could fine us or courts could award damages against us. We believe our properties comply with all significant legal requirements. However, these requirements could change in a way that would reduce our cash flow and ability to make distributions to shareholders.

We may incur significant environmental remediation costs: As an owner and operator of real properties, under various federal, state and local environmental laws, we are required to clean up spills or other releases of hazardous or toxic substances on or from our properties. Certain environmental laws impose liability whether or not the owner or buyer knew of, or was responsible for, the presence of the hazardous or toxic substances. In some cases, liability may not be limited to the value of the property. The presence of these substances, or the failure to properly remediate any resulting contamination, whether from environmental or microbial issues, also may adversely affect our ability to sell, lease, operate, or encumber our facilities for purposes of borrowing.

We have conducted preliminary environmental assessments of most of our properties (and conduct these assessments in connection with property acquisitions) to evaluate the environmental condition of, and potential environmental liabilities associated with, our properties. These assessments generally consist of an investigation of environmental conditions at the property (not including soil or groundwater sampling or analysis if appropriate), as well as a review of available information regarding the site and publicly available data regarding conditions at other sites in the vicinity. In connection with these property assessments, our operations and recent property acquisitions, we have become aware that prior operations or activities at some properties or from nearby locations have or may have resulted in contamination to the soil or groundwater at these properties. In circumstances where our environmental assessments disclose potential or actual contamination, we may attempt to obtain indemnifications and, in appropriate circumstances, we obtain limited environmental insurance in connection with the properties acquired, but we cannot assure you that such protections will be sufficient to cover actual future liabilities nor that our assessments have identified all such risks. Although we cannot provide any assurance, based on the preliminary environmental assessments, we are not aware of any environmental contamination of our facilities material to our overall business, financial condition or results of operations.

There has been an increasing number of claims and litigation against owners and managers of rental properties relating to moisture infiltration, which can result in mold or other property damage. When we receive a complaint concerning moisture infiltration, condensation or mold problems and/or become aware that an air quality concern exists, we implement corrective measures in accordance with guidelines and protocols we have developed with the assistance of outside experts. We seek to work proactively with our tenants to resolve

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moisture infiltration and mold-related issues, subject to our contractual limitations on liability for such claims. However, we can give no assurance that material legal claims relating to moisture infiltration and the presence of, or exposure to, mold will not arise in the future.

Property taxes can increase and cause a decline in yields on investments: Each of our properties is subject to real property taxes, which could increase in the future as property tax rates change and as our properties are assessed or reassessed by tax authorities. Recent local government shortfalls in tax revenue may cause pressure to increase tax rates or assessment levels or impose new taxes. Such increases could adversely impact our profitability.

We must comply with the Americans with Disabilities Act and fire and safety regulations, which can require significant expenditures: All our properties must comply with the Americans with Disabilities Act and with related regulations (the “ADA”). The ADA has separate compliance requirements for “public accommodations” and “commercial facilities,” but generally requires that buildings be made accessible to persons with disabilities. Various state laws impose similar requirements. A failure to comply with the ADA or similar state laws could lead to government imposed fines on us and/or litigation, which could also involve an award of damages to individuals affected by the non-compliance. In addition, we must operate our properties in compliance with numerous local fire and safety regulations, building codes, and other land use regulations. Compliance with these requirements can require us to spend substantial amounts of money, which would reduce cash otherwise available for distribution to shareholders. Failure to comply with these requirements could also affect the marketability of our real estate facilities.

We incur liability from tenant and employment-related claims: From time to time we have to make monetary settlements or defend actions or arbitration to resolve tenant or employment-related claims and disputes.

Global economic conditions adversely affect our business, financial condition, growth and access to capital.

There continues to be global economic uncertainty, elevated levels of unemployment, reduced levels of economic activity, and it is uncertain as to when economic conditions will improve. These negative economic conditions in the markets where we operate facilities, and other events or factors that adversely affect demand for commercial real estate, could continue to adversely affect our business. To the extent that turmoil in the financial markets returns or intensifies, it has the potential to materially affect the value of our properties, the availability or the terms of financing and may impact the ability of our customers to enter into new leasing transactions or satisfy rental payments under existing leases. The uncertainty and pace of an economic recovery could also affect our operating results and financial condition as follows:

Debt and Equity Markets: Our results of operations and share price are sensitive to volatility in the credit markets. The commercial real estate debt markets have experienced volatility as a result of various factors, including the tightening of underwriting standards by lenders and credit rating agencies. This has resulted in lenders increasing the cost for debt financing. Should the overall cost of borrowings increase, either by increases in the index rates or by increases in lender spreads, we will need to factor such increases into the economics of our acquisitions. In addition, the state of the debt markets could have an effect on the overall amount of capital being invested in real estate, which may result in price or value decreases of real estate assets and affect our ability to raise capital.

Our ability to issue preferred shares or obtain other sources of capital, such as borrowing, has been in the past, and may in the future, be adversely affected by challenging credit market conditions. The issuance of perpetual preferred securities historically has been a significant source of capital to grow our business. We believe that we have sufficient working capital and capacity under our credit facilities and our retained cash flow from operations to continue to operate our business as usual and meet our current obligations. However, if we were unable to issue preferred shares or borrow at reasonable rates, that could limit the earnings growth that might otherwise result from the acquisition and development of real estate facilities.

Valuations: Market volatility has made the valuation of our properties more difficult. There may be significant uncertainty in the valuation, or in the stability of the value, of our properties, which could result in a substantial decrease in the value of our properties. As a result, we may not be able to recover the carrying amount of our properties, which may require us to recognize an impairment charge in earnings.

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The acquisition of existing properties is a significant component of our long-term growth strategy, and acquisitions of existing properties are subject to risks that may adversely affect our growth and financial results.

We acquire existing properties, either in individual transactions or portfolios offered by other commercial real estate owners. In addition to the general risks related to real estate described above, we are also subject to the following risks which may jeopardize our realization of benefits from acquisitions.

Any failure to manage acquisitions and other significant transactions to achieve anticipated results and to successfully integrate acquired operations into our existing business could negatively impact our financial results: To fully realize anticipated earnings from an acquisition, we must successfully integrate the property into our operating platform. Failures or unexpected circumstances in the integration process, such as a failure to maintain existing relationships with tenants and employees due to changes in processes, standards, or compensation arrangements, or circumstances we did not detect during due diligence, could jeopardize realization of the anticipated earnings.

During 2012, we acquired 1.2 million square feet for an aggregate purchase price of $52.5 million. We continue to seek to acquire and develop multi-tenant flex, industrial and office properties where they meet our criteria, all of which we believe will enhance our future financial performance and the value of our portfolio. Our belief, however, is subject to risks, uncertainties and other factors, many of which are forward-looking and are uncertain in nature or are beyond our control, including the risks that our acquisitions and developments may not perform as expected, that we may be unable to quickly integrate new acquisitions and developments into our existing operations, and that any costs to develop projects or redevelop acquired properties may exceed estimates. As of December 31, 2012, the aggregate occupancy of the assets acquired in 2012 was 57.4%. If we are unable to lease the vacant square footage of these properties in a reasonable period of time, we may not be able to achieve our objective of enhancing value. Further, we face significant competition for suitable acquisition properties from other real estate investors, including other publicly traded real estate investment trusts and private institutional investors. As a result, we may be unable to acquire additional properties we desire or the purchase price for desirable properties may be significantly increased.

In addition, some of these properties may have unknown characteristics or deficiencies or may not complement our portfolio of existing properties. We may also finance future acquisitions and developments through a combination of borrowings, proceeds from equity or debt offerings by us or the Operating Partnership, and proceeds from property divestitures. These financing options may not be available when desired or required or may be more costly than anticipated, which could adversely affect our cash flow. Real property development is subject to a number of risks, including construction delays, complications in obtaining necessary zoning, occupancy and other governmental permits, cost overruns, financing risks, and the possible inability to meet expected occupancy and rent levels. If any of these problems occur, development costs for a project may increase, and there may be costs incurred for projects that are not completed. As a result of the foregoing, some properties may be worth less or may generate less revenue than, or simply not perform as well as, we believed at the time of acquisition or development, negatively affecting our operating results. Any of the foregoing risks could adversely affect our financial condition, operating results and cash flow, and our ability to pay dividends on, and the market price of, our stock. In addition, we may be unable to successfully integrate and effectively manage the properties we do acquire and develop, which could adversely affect our results of operations.

Acquired properties are subject to property tax reappraisals which may increase our property tax expense: Facilities that we acquire are subject to property tax reappraisal which can result in substantial increases to the ongoing property taxes paid by the seller. The reappraisal process is subject to judgment of governmental agencies regarding estimated real estate values and other factors, and as a result there is a significant degree of uncertainty in estimating the property tax expense of an acquired property. In connection with future or recent acquisitions of properties, if our estimates of property taxes following reappraisal are too low, we may not realize anticipated earnings from an acquisition.

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We would incur adverse tax consequences if we fail to qualify as a REIT.

Our cash flow would be reduced if we fail to qualify as a REIT: While we believe that we have qualified since 1990 to be taxed as a REIT, and will continue to be so qualified, we cannot be certain. To continue to qualify as a REIT, we need to satisfy certain requirements under the federal income tax laws relating to our income, assets, distributions to shareholders and shareholder base. In this regard, the share ownership limits in our articles of incorporation do not necessarily ensure that our shareholder base is sufficiently diverse for us to qualify as a REIT. For any year we fail to qualify as a REIT, we would be taxed at regular corporate tax rates on our taxable income unless certain relief provisions apply. Taxes would reduce our cash available for distributions to shareholders or for reinvestment, which could adversely affect us and our shareholders. Also we would not be allowed to elect REIT status for five years after we fail to qualify unless certain relief provisions apply.

We may need to borrow funds to meet our REIT distribution requirements: To qualify as a REIT, we must generally distribute to our shareholders 90% of our taxable income. Our income consists primarily of our share of our Operating Partnership’s income. We intend to make sufficient distributions to qualify as a REIT and otherwise avoid corporate tax. However, differences in timing between income and expenses and the need to make nondeductible expenditures such as capital improvements and principal payments on debt could force us to borrow funds to make necessary shareholder distributions.

PS has significant influence over us.

At December 31, 2012, PS owned 23.9% of the outstanding shares of the Company’s common stock and 23.1% of the outstanding common units of the Operating Partnership (100.0% of the common units not owned by the Company). Assuming issuance of the Company’s common stock upon redemption of its partnership units, PS would own 41.5% of the outstanding shares of the Company’s common stock. In addition, the PS Business Parks name and logo is owned by PS and licensed to the Company under a non-exclusive, royalty-free license agreement. The license can be terminated by either party for any reason with six months written notice. Ronald L. Havner, Jr., the Company’s chairman, is also Chairman of the Board, Chief Executive Officer and President of PS. Consequently, PS has the ability to significantly influence all matters submitted to a vote of our shareholders, including electing directors, changing our articles of incorporation, dissolving and approving other extraordinary transactions such as mergers, and all matters requiring the consent of the limited partners of the Operating Partnership. PS’s interest in such matters may differ from other shareholders. In addition, PS’s ownership may make it more difficult for another party to take over our Company without PS’s approval.

Provisions in our organizational documents may prevent changes in control.

Our articles generally prohibit any person from owning more than 7% of our shares: Our articles of incorporation restrict the number of shares that may be owned by any other person, and the partnership agreement of our Operating Partnership contains an anti-takeover provision. No shareholder (other than PS and certain other specified shareholders) may own more than 7% of the outstanding shares of our common stock, unless our board of directors waives this limitation. We imposed this limitation to avoid, to the extent possible, a concentration of ownership that might jeopardize our ability to qualify as a REIT. This limitation, however, also makes a change of control much more difficult (if not impossible) even if it may be favorable to our public shareholders. These provisions will prevent future takeover attempts not supported by PS even if a majority of our public shareholders consider it to be in their best interests as they would receive a premium for their shares over market value or for other reasons.

Our board can set the terms of certain securities without shareholder approval: Our board of directors is authorized, without shareholder approval, to issue up to 50.0 million shares of preferred stock and up to 100.0 million shares of equity stock, in each case in one or more series. Our board has the right to set the terms of each of these series of stock. Consequently, the board could set the terms of a series of stock that could make it difficult (if not impossible) for another party to take over our Company even if it might be favorable to our public shareholders. Our articles of incorporation also contain other provisions that could have the same effect. We can also cause our Operating Partnership to issue additional interests for cash or in exchange for property.

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The partnership agreement of our Operating Partnership restricts mergers: The partnership agreement of our Operating Partnership generally provides that we may not merge or engage in a similar transaction unless the limited partners of our Operating Partnership are entitled to receive the same proportionate payments as our shareholders. In addition, we have agreed not to merge unless the merger would have been approved had the limited partners been able to vote together with our shareholders, which has the effect of increasing PS’s influence over us due to PS’s ownership of operating partnership units. These provisions may make it more difficult for us to merge with another entity.

Our Operating Partnership poses additional risks to us.

Limited partners of our Operating Partnership, including PS, have the right to vote on certain changes to the partnership agreement. They may vote in a way that is against the interests of our shareholders. Also, as general partner of our Operating Partnership, we are required to protect the interests of the limited partners of the Operating Partnership. The interests of the limited partners and of our shareholders may differ.

We depend on external sources of capital to grow our Company.

We are generally required under the Internal Revenue Code to distribute at least 90% of our taxable income. Because of this distribution requirement, we may not be able to fund future capital needs, including any necessary building and tenant improvements, from operating cash flow. Consequently, we may need to rely on third-party sources of capital to fund our capital needs. We may not be able to obtain the financing on favorable terms or at all. Access to third-party sources of capital depends, in part, on general market conditions, the market’s perception of our growth potential, our current and expected future earnings, our cash flow, and the market price per share of our common stock. If we cannot obtain capital from third-party sources, we may not be able to acquire properties when strategic opportunities exist, satisfy any debt service obligations, or make cash distributions to shareholders.

We are subject to laws and governmental regulations and actions that affect our operating results and financial condition.

Our business is subject to regulation under a wide variety of U.S. federal, state and local laws, regulations and policies including those imposed by the SEC, the Sarbanes-Oxley Act of 2002, the Dodd-Frank Wall Street Reform and Consumer Protection Act and New York Stock Exchange, as well as applicable labor laws. Although we have policies and procedures designed to comply with applicable laws and regulations, failure to comply with the various laws and regulations may result in civil and criminal liability, fines and penalties, increased costs of compliance and restatement of our financial statements.

There can also be no assurance that, in response to current economic conditions or the current political environment or otherwise, laws and regulations will not be implemented or changed in ways that adversely affect our operating results and financial condition, such as recently adopted legislation that expands health care coverage costs or facilitates union activity or federal legislative proposals to otherwise increase operating costs.

Terrorist attacks and the possibility of wider armed conflict may have an adverse impact on our business and operating results and could decrease the value of our assets.

Terrorist attacks and other acts of violence or war could have a material adverse impact on our business and operating results. There can be no assurance that there will not be further terrorist attacks against the U.S. Attacks or armed conflicts that directly impact one or more of our properties could significantly affect our ability to operate those properties and thereby impair our operating results. Further, we may not have insurance coverage for losses caused by a terrorist attack. Such insurance may not be available, or if it is available and we decide to obtain such terrorist coverage, the cost for the insurance may be significant in relationship to the risk overall. In addition, the adverse effects that such violent acts and threats of future attacks could have on the U.S. economy could similarly have a material adverse effect on our business and results of operations. Finally, further terrorist acts could cause the U.S. to enter into a wider armed conflict, which could further impact our business and operating results.

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Developments in California may have an adverse impact on our business and financial results.

We are headquartered in, and approximately 39.4% of our properties are located in California, which like many other state and local jurisdictions is facing severe budgetary problems and deficits. Actions have been and may continue to be taken in response to these problems, such as increases in property taxes, changes to sales taxes or other governmental efforts to raise revenues could adversely impact our business and results of operations.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

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ITEM 2. PROPERTIES

As of December 31, 2012, the Company owned 102 business parks consisting of a geographically diverse portfolio of 28.3 million rentable square feet of commercial real estate which consists of 14.9 million square feet of flex space, 8.4 million square feet of industrial space and 5.0 million square feet of office space concentrated primarily in eight states consisting of California, Virginia, Florida, Texas, Maryland, Washington, Oregon and Arizona. The weighted average occupancy rate throughout 2012 was 89.0% and the realized rent per square foot was $14.05.

The following table reflects the geographical diversification of the 102 business parks owned by the Company as of December 31, 2012, the type of the rentable square footage and the weighted average occupancy rates throughout 2012 (except as set forth below, all of the properties are held in fee simple interest) (in thousands, except number of business parks):

	Number  of Business Parks										Weighted Average Occupancy Rate
			Rentable Square Footage
State			Flex		Industrial		Office		Total
California (1)		48		5,356		4,618		1,167		11,141		87.4	%
Virginia		17		1,947		—		2,218		4,165		88.1	%
Florida (1)		3		1,074		2,631		12		3,717		95.7	%
Texas (2)		18		3,255		231		—		3,486		93.2	%
Maryland		6		970		—		1,382		2,352		87.3	%
Washington		3		493		958		28		1,479		73.8	%
Oregon		3		1,126		—		188		1,314		89.2	%
Arizona		4		679		—		—		679		90.7	%
Total		102		14,900		8,438		4,995		28,333		89.0	%

(1) The Company has 5.4 million square feet, 5.1 million square feet in California and 307,000 square feet in Florida which serves as collateral to mortgage notes payable. For more information, see Note 6 to the consolidated financial statements.

(2) The Company owns two properties that are subject to ground leases in Las Colinas, Texas, expiring in 2019 and 2020, each with one 10 year extension option.

We currently anticipate that each of the properties listed above will continue to be used for its current purpose. Competition exists in each of the market areas in which these properties are located.

The Company has no plans to change the current use of its properties. The Company typically renovates its properties in connection with the re-leasing of space to tenants and expects that it will pay the costs of such renovations from rental income. The Company has risks that tenants will default on leases and declare bankruptcy. Management believes these risks are mitigated through the Company’s geographic diversity and diverse tenant base.

The Company evaluates the performance of its business parks primarily based on net operating income (“NOI”). NOI is defined by the Company as rental income as defined by GAAP less cost of operations as defined by GAAP, excluding depreciation and amortization. The Company uses NOI and its components as a measurement of the performance of its commercial real estate. Management believes that these financial measures provide them, as well as the investor, the most consistent measurement on a comparative basis of the performance of the commercial real estate and its contribution to the value of the Company. Depreciation and amortization have been excluded from NOI as they are generally not used in determining the value of commercial real estate by management or the investment community. Depreciation and amortization are generally not used in determining value as they consider the historical costs of an asset compared to its current value; therefore, to understand the effect of the assets’ historical cost on the Company’s results, investors should look at GAAP financial measures, such as total operating costs including depreciation and amortization. The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance calculated in accordance with GAAP. As part of the table below, we have reconciled total NOI to income from continuing operations, which we consider the most directly comparable financial measure calculated in accordance with GAAP. The following information illustrates rental income, cost of operations and NOI generated by the Company’s total portfolio in 2012, 2011 and 2010 by state and by property classifications. As a result of acquisitions and dispositions, certain properties were not held for the full year.

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The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance in accordance with GAAP. The tables below also include a reconciliation of NOI to the most comparable amounts based on GAAP (in thousands):

	For the Year Ended December 31, 2012								For the Year Ended December 31, 2011								For the Year Ended December 31, 2010
	Flex		Office		Industrial		Total		Flex		Office		Industrial		Total		Flex		Office		Industrial		Total
Rental Income:
California	$	62,618	$	18,550	$	33,210	$	114,378	$	48,014	$	18,557	$	8,517	$	75,088	$	49,601	$	20,561	$	8,096	$	78,258
Virginia		36,126		48,096		—		84,222		32,829		42,030		—		74,859		33,464		25,665		—		59,129
Florida		10,686		206		20,649		31,541		10,592		235		20,250		31,077		10,228		216		20,076		30,520
Texas		32,878		—		1,297		34,175		30,867		—		1,308		32,175		27,898		—		1,265		29,163
Maryland		15,470		33,495		—		48,965		20,098		32,783		—		52,881		17,218		29,762		—		46,980
Washington		7,628		521		1,338		9,487		7,894		589		—		8,483		7,738		552		—		8,290
Oregon		14,659		3,399		—		18,058		14,029		3,210		—		17,239		15,094		3,049		—		18,143
Arizona		5,722		—		—		5,722		5,655		—		—		5,655		5,793		—		—		5,793
Total		185,787		104,267		56,494		346,548		169,978		97,404		30,075		297,457		167,034		79,805		29,437		276,276
Cost of Operations:
California		20,069		7,878		9,583		37,530		14,748		7,799		2,151		24,698		14,732		8,015		1,745		24,492
Virginia		8,745		17,396		—		26,141		8,761		16,420		—		25,181		8,381		8,665		—		17,046
Florida		3,913		173		6,057		10,143		3,975		165		6,033		10,173		3,752		134		6,041		9,927
Texas		11,224		—		410		11,634		10,687		—		339		11,026		10,253		—		335		10,588
Maryland		4,741		11,058		—		15,799		5,182		11,261		—		16,443		5,160		10,036		—		15,196
Washington		2,380		195		675		3,250		2,420		201		—		2,621		2,438		193		—		2,631
Oregon		5,650		1,412		—		7,062		5,626		1,415		—		7,041		5,326		1,393		—		6,719
Arizona		2,549		—		—		2,549		2,734		—		—		2,734		2,749		—		—		2,749
Total		59,271		38,112		16,725		114,108		54,133		37,261		8,523		99,917		52,791		28,436		8,121		89,348
NOI:
California		42,549		10,672		23,627		76,848		33,266		10,758		6,366		50,390		34,869		12,546		6,351		53,766
Virginia		27,381		30,700		—		58,081		24,068		25,610		—		49,678		25,083		17,000		—		42,083
Florida		6,773		33		14,592		21,398		6,617		70		14,217		20,904		6,476		82		14,035		20,593
Texas		21,654		—		887		22,541		20,180		—		969		21,149		17,645		—		930		18,575
Maryland		10,729		22,437		—		33,166		14,916		21,522		—		36,438		12,058		19,726		—		31,784
Washington		5,248		326		663		6,237		5,474		388		—		5,862		5,300		359		—		5,659
Oregon		9,009		1,987		—		10,996		8,403		1,795		—		10,198		9,768		1,656		—		11,424
Arizona		3,173		—		—		3,173		2,921		—		—		2,921		3,044		—		—		3,044
Total	$	126,516	$	66,155	$	39,769	$	232,440	$	115,845	$	60,143	$	21,552	$	197,540	$	114,243	$	51,369	$	21,316	$	186,928

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The following table is provided to reconcile NOI to consolidated income from continuing operations as determined by GAAP (in thousands):

	For The Years Ended December 31,
	2012			2011			2010
Property net operating income	$	232,440		$	197,540		$	186,928
Facility management fees		649			684			672
Interest and other income		241			221			333
Depreciation and amortization		(109,398	)		(84,391	)		(78,354	)
General and administrative		(8,919	)		(9,036	)		(9,651	)
Interest expense		(20,618	)		(5,455	)		(3,534	)
Income from continuing operations	$	94,395		$	99,563		$	96,394

Portfolio Information

The table below sets forth information with respect to occupancy and rental rates of the Company’s total portfolio for each of the last five years, including discontinued operations:

	2012(1)			2011(1)			2010			2009			2008
Weighted average occupancy rate		89.0	%		89.2	%		90.8	%		90.5	%		93.5	%
Realized rent per square foot	$	14.05		$	15.10		$	14.96		$	15.45		$	15.50

(1) Exclude lease buyout payments of $1.8 million and $2.9 million for the years ended December 31, 2012 and 2011, respectively.

The following table set forth the lease expirations for all assets in continuing operations as of December 31, 2012 (in thousands):

Lease Expirations as of December 31, 2012

Year of Lease Expiration	Number of Tenants		Rentable Square Footage  Subject to Expiring Leases		Annualized Rental Income Under Expiring Leases		Percent of Annualized Rental Income  Represented by Expiring Leases
2013		2,040		7,361	$	100,891		27.7	%
2014		1,218		5,632		78,989		21.7	%
2015		713		4,349		59,679		16.4	%
2016		290		3,147		47,173		13.0	%
2017		195		2,188		31,007		8.5	%
2018		60		755		15,861		4.4	%
2019		25		784		8,648		2.4	%
2020		17		457		7,812		2.1	%
2021		14		290		4,882		1.3	%
2022		18		248		6,169		1.7	%
Thereafter		8		176		3,056		0.8	%
Total		4,598		25,387	$	364,167		100.0	%

ITEM 3. LEGAL PROCEEDINGS

We are not presently subject to material litigation nor, to our knowledge, is any material litigation threatened against us, other than routine actions for negligence and other claims and administrative proceedings arising in the ordinary course of business, some of which are expected to be covered by liability insurance or third party indemnifications and all of which collectively we do not expect to have a material adverse effect on our financial condition, results of operations, or liquidity.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

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PART II

ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Market Price of the Registrant’s Common Equity:

The common stock of the Company trades on the New York Stock Exchange under the symbol PSB. The following table sets forth the high and low sales prices of the common stock on the New York Stock Exchange for the applicable periods:

	Range
Three Months Ended	High		Low
March 31, 2011	$	63.16	$	55.63
June 30, 2011	$	61.10	$	52.13
September 30, 2011	$	59.49	$	46.39
December 31, 2011	$	56.87	$	46.19
March 31, 2012	$	65.60	$	55.55
June 30, 2012	$	69.59	$	63.90
September 30, 2012	$	71.72	$	63.66
December 31, 2012	$	68.05	$	63.24

Holders:

As of February 18, 2013, there were 395 holders of record of the common stock.

Dividends:

Holders of common stock are entitled to receive distributions when, as and if declared by the Company’s Board of Directors out of any funds legally available for that purpose. The Company is required to distribute at least 90% of its taxable income prior to the filing of the Company’s tax return to maintain its REIT status for federal income tax purposes. It is management’s intention to pay distributions of not less than these required amounts.

Distributions paid per share of common stock for the years ended December 31, 2012 and 2011 amounted to $1.76 per year. The Board of Directors has established a distribution policy intended to maximize the retention of operating cash flow and distribute the amount required for the Company to maintain its tax status as a REIT.

Issuer Repurchases of Equity Securities:

The Company’s Board of Directors previously authorized the repurchase, from time to time, of up to 6.5 million shares of the Company’s common stock on the open market or in privately negotiated transactions. During the three months ended December 31, 2012, there were no shares of the Company’s common stock repurchased. As of December 31, 2012, the Company has 1,614,721 shares available for purchase under the program. The program does not expire. Purchases will be made subject to market conditions and other investment opportunities available to the Company.

Securities Authorized for Issuance Under Equity Compensation Plans:

The equity compensation plan information is provided in Item 12.

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ITEM 6. SELECTED FINANCIAL DATA

The following sets forth selected consolidated financial and operating information on a historical basis of the Company. The following information should be read in conjunction with the consolidated financial statements and notes thereto of the Company included elsewhere in this Form 10-K. Note that historical results from 2011 through 2008 were reclassified to conform to 2012 presentation for discontinued operations. See Note 3 to the consolidated financial statements included elsewhere in this Form 10-K for a discussion of income from discontinued operations.

	For The Years Ended December 31,
	2012			2011			2010			2009			2008
	(In thousands, except per share data)
Revenues:
Rental income	$	346,548		$	297,457		$	276,276		$	268,551		$	278,763
Facility management fees		649			684			672			698			728
Total operating revenues		347,197			298,141			276,948			269,249			279,491
Expenses:
Cost of operations		114,108			99,917			89,348			84,771			86,143
Depreciation and amortization		109,398			84,391			78,354			83,892			98,648
General and administrative		8,919			9,036			9,651			6,202			8,099
Total operating expenses		232,425			193,344			177,353			174,865			192,890
Other income and (expenses):
Interest and other income		241			221			333			536			1,457
Interest expense		(20,618	)		(5,455	)		(3,534	)		(3,552	)		(3,952	)
Total other income and (expenses)		(20,377	)		(5,234	)		(3,201	)		(3,016	)		(2,495	)
Income from continuing operations		94,395			99,563			96,394			91,368			84,106
Discontinued operations:
Income from discontinued operations		42			360			475			1,483			1,241
Gain on sale of real estate facility		935			2,717			5,153			1,488			—
Total discontinued operations		977			3,077			5,628			2,971			1,241
Net income	$	95,372		$	102,640		$	102,022		$	94,339		$	85,347
Net income allocation:
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units	$	5,970		$	15,543		$	11,594		$	19,730		$	8,296
Noncontrolling interests — preferred units		323			(6,991	)		5,103			(2,569	)		7,007
Total net income allocable to noncontrolling interests		6,293			8,552			16,697			17,161			15,303
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders		69,136			41,799			46,214			17,440			46,630
Restricted stock unit holders		138			127			152			325			235
Common shareholders		19,805			52,162			38,959			59,413			23,179
Total net income allocable to PS Business Parks, Inc.		89,079			94,088			85,325			77,178			70,044
Net income	$	95,372		$	102,640		$	102,022		$	94,339		$	85,347

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	For The Years Ended December 31,
	2012			2011			2010			2009			2008
	(In thousands, except per share data)
Per Common Share:
Cash Distributions	$	1.76		$	1.76		$	1.76		$	1.76		$	1.76
Net income — basic	$	0.82		$	2.13		$	1.59		$	2.70		$	1.13
Net income — diluted	$	0.81		$	2.12		$	1.58		$	2.68		$	1.12
Weighted average common shares — basic		24,234			24,516			24,546			21,998			20,443
Weighted average common shares — diluted		24,323			24,599			24,687			22,128			20,618
Balance Sheet Data:
Total assets	$	2,151,817		$	2,138,619		$	1,621,057		$	1,564,822		$	1,469,323
Total debt	$	468,102		$	717,084		$	144,511		$	52,887		$	59,308
Equity:
PS Business Parks, Inc.’s shareholders’ equity:
Preferred stock	$	885,000		$	598,546		$	598,546		$	626,046		$	706,250
Common stock	$	560,689		$	580,659		$	594,982		$	589,633		$	414,564
Noncontrolling interests:
Preferred units	$	—		$	5,583		$	53,418		$	73,418		$	94,750
Common units	$	168,572		$	175,807		$	176,179		$	176,540		$	148,023
Other Data:
Net cash provided by operating activities	$	209,127		$	180,620		$	177,116		$	179,625		$	189,337
Net cash used in investing activities	$	(105,729	)	$	(337,106	)	$	(326,623	)	$	(26,956	)	$	(35,192	)
Net cash (used in) provided by financing activities	$	(95,495	)	$	156,400		$	(53,656	)	$	545		$	(134,171	)
Funds from operations (1)	$	134,472		$	149,797		$	124,420		$	163,074		$	131,558
Square footage owned at end of period		28,333			27,215			21,791			19,556			19,556

(1) Funds from operations (“FFO”) is computed in accordance with the White Paper on FFO approved by the Board of Governors of NAREIT. The White Paper defines FFO as net income, computed in accordance with GAAP, before depreciation, amortization, gains or losses on asset dispositions, net income allocable to noncontrolling interests — common units, net income allocable to restricted stock unit holders, impairment charges and nonrecurring items. FFO should be analyzed in conjunction with net income. However, FFO should not be viewed as a substitute for net income as a measure of operating performance or liquidity as it does not reflect depreciation and amortization costs or the level of capital expenditure and leasing costs necessary to maintain the operating performance of the Company’s properties, which are significant economic costs and could materially impact the Company’s results of operations. Other REITs may use different methods for calculating FFO and, accordingly, the Company’s FFO may not be comparable to that of other real estate companies. See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Liquidity and Capital Resources — Funds from Operations,” for a reconciliation of FFO and net income allocable to common shareholders and for information on why the Company presents FFO.

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ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis of the results of operations and financial condition should be read in conjunction with the selected financial data and the Company’s consolidated financial statements and notes thereto included elsewhere in the Form 10-K.

Overview

As of December 31, 2012, the Company owned and operated 28.3 million rentable square feet of multi-tenant flex, industrial and office properties located in eight states.

The Company focuses on increasing profitability and cash flow aimed at maximizing shareholder value. The Company strives to maintain high occupancy levels while increasing rental rates when market conditions allow, although the Company may decrease rental rates in markets where conditions require. The Company also acquires properties it believes will create long-term value, and from time to time disposes of properties which no longer fit within the Company’s strategic objectives or in situations where the Company believes it can optimize cash proceeds. Operating results are driven primarily by income from rental operations and are therefore substantially influenced by rental demand for space within our properties and our markets, which impacts occupancy and rental rates.

During 2012, the Company executed leases comprising 8.0 million square feet of space including 4.4 million square feet of renewals of existing leases and 3.6 million square feet of new leases. Overall, the Company experienced a decrease in rental rates when comparing new rental rates to outgoing rental rates of 6.2%. See further discussion of operating results below.

Critical Accounting Policies and Estimates:

Our accounting policies are described in Note 2 to the consolidated financial statements included in this Form 10-K. We believe our most critical accounting policies relate to revenue recognition, property acquisitions, allowance for doubtful accounts, impairment of long-lived assets, depreciation, accruals of operating expenses and accruals for contingencies, each of which we discuss below.

Revenue Recognition: The Company must meet four basic criteria before revenue can be recognized: persuasive evidence of an arrangement exists; the delivery has occurred or services rendered; the fee is fixed or determinable; and collectability is reasonably assured. All leases are classified as operating leases. Rental income is recognized on a straight-line basis over the terms of the leases. Straight-line rent is recognized for all tenants with contractual fixed increases in rent that are not included on the Company’s credit watch list. Deferred rent receivable represents rental revenue recognized on a straight-line basis in excess of billed rents. Reimbursements from tenants for real estate taxes and other recoverable operating expenses are recognized as rental income in the period the applicable costs are incurred. Property management fees are recognized in the period earned.

Property Acquisitions: The Company records the purchase price of acquired properties to land, buildings and improvements and intangible assets and liabilities associated with in-place leases (including tenant improvements, unamortized lease commissions, value of above-market and below-market leases, acquired in-place lease values, and tenant relationships, if any) based on their respective estimated fair values. Acquisition related costs are expensed as incurred.

In determining the fair value of the tangible assets of the acquired properties, management considers the value of the properties as if vacant as of the acquisition date. Management must make significant assumptions in determining the value of assets acquired and liabilities assumed. Using different assumptions in the recording of the purchase cost of the acquired properties would affect the timing of recognition of the related revenue and expenses. Amounts recorded to land are derived from comparable sales of land within the same region. Amounts recorded to buildings and improvements, tenant improvements and unamortized lease commissions are based on current market replacement costs and other market rate information.

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The value recorded to the above-market or below-market in-place lease values of acquired properties is determined based upon the present value (using a discount rate which reflects the risks associated with the acquired leases) of the difference between (i) the contractual rents to be paid pursuant to the in-place leases, and (ii) management’s estimate of fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. The amounts recorded to above-market or below-market leases are included in other assets or other liabilities in the accompanying consolidated balance sheets and are amortized on a straight-line basis as an increase or reduction of rental income over the remaining non-cancelable term of the respective leases.

Allowance for Doubtful Accounts: Rental revenue from our tenants is our principal source of revenue. We monitor the collectability of our receivable balances including the deferred rent receivable on an ongoing basis. Based on these reviews, we maintain an allowance for doubtful accounts for estimated losses resulting from the possible inability of our tenants to make required rent payments to us. Tenant receivables and deferred rent receivables are carried net of the allowances for uncollectible tenant receivables and deferred rent. As discussed below, determination of the adequacy of these allowances requires significant judgments and estimates. Our estimate of the required allowance is subject to revision as the factors discussed below change and is sensitive to the effect of economic and market conditions on our tenants.

Tenant receivables consist primarily of amounts due for contractual lease payments, reimbursements of common area maintenance expenses, property taxes and other expenses recoverable from tenants. Determination of the adequacy of the allowance for uncollectible current tenant receivables is performed using a methodology that incorporates specific identification, aging analysis, an overall evaluation of the historical loss trends and the current economic and business environment. The specific identification methodology relies on factors such as the age and nature of the receivables, the payment history and financial condition of the tenant, the assessment of the tenant’s ability to meet its lease obligations, and the status of negotiations of any disputes with the tenant. The allowance also includes a reserve based on historical loss trends not associated with any specific tenant. This reserve as well as the specific identification reserve is reevaluated quarterly based on economic conditions and the current business environment.

Deferred rent receivable represents the amount that the cumulative straight-line rental income recorded to date exceeds cash rents billed to date under the lease agreement. Given the long-term nature of these types of receivables, determination of the adequacy of the allowance for unbilled deferred rent receivable is based primarily on historical loss experience. Management evaluates the allowance for unbilled deferred rent receivable using a specific identification methodology for significant tenants designed to assess their financial condition and ability to meet their lease obligations.

Impairment of Long-Lived Assets: The Company evaluates a property for potential impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable. On a quarterly basis, we evaluate our entire portfolio for impairment based on current operating information. In the event that these periodic assessments reflect that the carrying amount of a property exceeds the sum of the undiscounted cash flows (excluding interest) that are expected to result from the use and eventual disposition of the property, the Company would recognize an impairment loss to the extent the carrying amount exceeded the estimated fair value of the property. The estimation of expected future net cash flows is inherently uncertain and relies on subjective assumptions dependent upon future and current market conditions and events that affect the ultimate value of the property. Management must make assumptions related to the property such as future rental rates, tenant allowances, operating expenditures, property taxes, capital improvements, occupancy levels and the estimated proceeds generated from the future sale of the property. These assumptions could differ materially from actual results in future periods. Our intent to hold properties over the long-term directly decreases the likelihood of recording an impairment loss. If our strategy changes or if market conditions otherwise dictate an earlier sale date, an impairment loss could be recognized, and such loss could be material.

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Depreciation: We compute depreciation on our buildings and improvements using the straight-line method based on estimated useful lives generally ranging from five to 30 years. A significant portion of the acquisition cost of each property is recorded to building and building components. The recording of the acquisition cost to building and building components, as well as the determination of their useful lives, are based on estimates. If we do not appropriately record to these components or we incorrectly estimate the useful lives of these components, our computation of depreciation expense may not appropriately reflect the actual impact of these costs over future periods, which will affect net income. In addition, the net book value of real estate assets could be overstated or understated. The statement of cash flows, however, would not be affected.

Accruals of Operating Expenses: The Company accrues for property tax expenses, performance bonuses and other operating expenses each quarter based on historical trends and anticipated disbursements. If these estimates are incorrect, the timing and amount of expense recognized will be affected.

Accruals for Contingencies: The Company is exposed to business and legal liability risks with respect to events that may have occurred, but in accordance with GAAP has not accrued for such potential liabilities because the loss is either not probable or not estimable. Future events could result in such potential losses becoming probable and estimable, which could have a material adverse impact on our financial condition or results of operations.

Effect of Economic Conditions on the Company’s Operations: During 2012, while certain markets reflected signs of improved occupancy, overall the Company continued to experience decreases in new rental rates over expiring rental rates on executed leases as a result of a slow recovery of economic conditions combined with continued competitive conditions within the commercial real estate environment. The rate of decrease eased from 8.3% for the year ended December 31, 2011 to 6.2% for the year ended December 31, 2012. Although it is uncertain what impact economic conditions and competition will have on the Company’s future ability to maintain existing occupancy levels and rental rates, management believes that the decrease in rental rates on lease transactions could negatively impact rental income for 2013. Current and future economic conditions may continue to have a significant impact on the Company, potentially resulting in further reductions in occupancy and rental rates.

The Company historically has experienced a low level of write-offs of uncollectable rents, however, there is inherent uncertainty in a tenant’s ability to continue paying rent and meet their full lease obligation. The table below summarizes the impact to the Company from tenants’ inability to pay rent or continue to meet their lease obligations (in thousands):

	For The Years Ended December 31,
	2012			2011			2010
Annual write — offs of uncollectible rent	$	1,115		$	1,172		$	1,464
Annual write — offs as a percentage of annual rental income		0.3	%		0.4	%		0.5	%
Square footage of leases terminated prior to scheduled expiration due to business failures/bankruptcies		570			536			572
Accelerated depreciation expense related to unamortized tenant improvements and lease commissions associated with early terminations	$	1,493		$	1,370		$	2,779

As of February 22, 2013, the Company had 30,000 square feet of leased space occupied by tenants that are protected by Chapter 11 of the U.S. Bankruptcy Code. From time to time, tenants contact us, requesting early termination of their lease, a reduction in space under lease, or rent deferment or abatement. At this time, the Company cannot anticipate what impact, if any, the ultimate outcome of these discussions will have on our future operating results.

Company Performance and Effect of Economic Conditions on Primary Markets: The Company’s operations are substantially concentrated in 10 regions. During the year ended December 31, 2012, initial rental rates on new and renewed leases within the Company’s overall portfolio decreased 6.2% over expiring rents, an improvement from a decline of 8.3% for the year ended December 31, 2011. The Company’s Same Park (defined below) occupancy rate at December 31, 2012 was 92.7%, compared to 92.6% at December 31, 2011. The

25

Company’s overall occupancy rate at December 31, 2012 was 89.5%, compared to 88.9% at December 30, 2011. Each of the 10 regions in which the Company owns assets is subject to its own unique market influences. See “Supplemental Property Data and Trends” below for more information on regional operating data.

Growth of the Company’s Operations from Acquisitions and Dispositions of Properties: The Company is focused on maximizing cash flow from its existing portfolio of properties by looking for opportunities to expand its presence in existing and new markets through strategic acquisitions. The Company may from time to time dispose of non-strategic assets that do not meet this criterion. The Company has historically maintained a low-leverage-level approach intended to provide the Company with the greatest level of flexibility for future growth.

On December 19, 2012, the Company acquired three multi-tenant flex buildings in Austin, Texas, aggregating 226,000 square feet, for a purchase price of $14.9 million. In connection with this purchase, the Company received a $592,000 credit for committed tenant improvements and lease commissions. On July 24, 2012, the Company acquired a 958,000 square foot industrial park consisting of eight single-story buildings located in Kent Valley, Washington, for a purchase price of $37.6 million.

As of December 31, 2012, the blended occupancy rate of the 11 assets acquired from 2010 through 2012 was 82.6% compared to a blended occupancy rate of 75.1% at the time of acquisition. As of December 31, 2012, the Company had 1.6 million square feet of vacancy spread over these 11 acquisitions which we believe provides the Company with considerable opportunity to generate additional rental income given that the Company’s Same Park assets in these same submarkets have a weighted occupancy of 94.9% at December 31, 2012. The table below contains the assets acquired from 2010 through 2012 (in thousands):

Property	Date Acquired	Location	Purchase Price		Square Feet		Occupancy  at Acquisition			Occupancy at December 31,  2012
Austin Flex Buildings	December, 2012	Austin, Texas	$	14,900		226		86.1	%		86.1	%
212th Business Park	July, 2012	Kent Valley, Washington		37,550		958		52.3	%		50.7	%
Northern California Portfolio	December, 2011	East Bay, California		520,000		5,334		82.2	%		86.3	%
Royal Tech	October, 2011	Las Colinas, Texas		2,835		80		0.0	%		100.0	%
MICC — Center 22	August, 2011	Miami, Florida		3,525		46		33.3	%		33.3	%
Warren Building	June, 2011	Tysons Corner, Virginia		27,100		140		68.0	%		88.2	%
Westpark Business Campus	December, 2010	Tysons Corner, Virginia		140,000		735		61.9	%		74.7	%
Tysons Corporate Center	July, 2010	Tysons Corner, Virginia		35,400		270		47.0	%		88.4	%
Parklawn Business Park	June, 2010	Rockville, Maryland		23,430		232		70.6	%		88.0	%
Austin Flex Portfolio	April, 2010	Austin, Texas		42,900		704		88.0	%		96.6	%
Shady Grove Executive Center	March, 2010	Rockville, Maryland		60,000		350		73.5	%		92.2	%
Total			$	907,640		9,075		75.1	%		82.6	%

In 2010, the Company also completed construction on a parcel of land within MICC in Miami, Florida, which added 75,000 square feet of rentable small tenant industrial space.

In October, 2012, the Company completed the sale of Quail Valley Business Park, a 66,000 square foot flex park in Houston, Texas, for a gross sales price of $2.3 million, resulting in a net gain of $935,000.

In August, 2011, the Company completed the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million.

In January, 2010, the Company completed the sale of a 131,000 square foot office building located in Houston, Texas, for a gross sales price of $10.0 million, resulting in a net gain of $5.2 million.

Scheduled Lease Expirations: In addition to the 3.0 million square feet, or 10.5%, of space available in our total portfolio as of December 31, 2012, 2,040 leases representing 29.0% of the leased square footage of our total portfolio or 27.7% of annualized rental income are scheduled to expire in 2013. Our ability to re-lease available space will depend upon market conditions in the specific submarkets in which our properties are located. We cannot predict with certainty the rate at which expiring leases will be re-leased.

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Impact of Inflation: Although inflation has not been significant in recent years, it remains a potential factor in our economy, and the Company continues to seek ways to mitigate its potential impact. A substantial portion of the Company’s leases require tenants to pay operating expenses, including real estate taxes, utilities, and insurance, as well as increases in common area expenses, partially reducing the Company’s exposure to inflation.

Concentration of Portfolio by Region: The table below reflects the Company’s square footage from continuing operations based on regional concentration as of December 31, 2012 (in thousands):

Region	Square Footage		Percent of Square Footage			2012 NOI			Percent of NOI
California
Northern California		7,153		25.3	%	$	42,286			18.2	%
Southern California		3,988		14.1	%		34,562			14.9	%
Virginia		4,165		14.7	%		58,081			25.0	%
Florida		3,717		13.1	%		21,398			9.2	%
Texas
Northern Texas		1,769		6.2	%		11,940			5.1	%
Southern Texas		1,717		6.1	%		10,601			4.5	%
Maryland		2,352		8.3	%		33,166			14.3	%
Washington		1,479		5.2	%		6,237			2.7	%
Oregon		1,314		4.6	%		10,996			4.7	%
Arizona		679		2.4	%		3,173			1.4	%
Total		28,333		100.0	%	$	232,440			100.0	%
Reconciliation of NOI to income from continuing operations
Total NOI						$	232,440
Other income and (expenses):
Facilities management fees							649
Interest and other income							241
Interest expense							(20,618	)
Depreciation and amortization							(109,398	)
General and administrative							(8,919	)
Income from continuing operations						$	94,395

Concentration of Credit Risk by Industry: The information below depicts the industry concentration of our tenant base as of December 31, 2012. The Company analyzes this concentration to minimize significant industry exposure risk.

Industry	Percent of Annualized Rental Income
Business services		15.2	%
Health services		11.1	%
Government		10.6	%
Computer hardware, software and related services		10.2	%
Warehouse, distribution, transportation and logistics		9.1	%
Insurance and financial services		6.1	%
Engineering and construction		5.8	%
Retail, food and automotive		5.5	%
Communications		4.7	%
Aerospace/defense products and services		3.3	%
Electronics		3.3	%
Home furnishings		3.3	%
Educational services		1.8	%
Other		10.0	%
Total		100.0	%

27

The information below depicts the Company’s top 10 customers by annualized rental income as of December 31, 2012 (in thousands):

Tenants	Square Footage		Annualized Rental Income(1)		Percent of Annualized Rental Income
U.S. Government		870	$	21,461		6.1	%
Lockheed Martin Corporation		176		4,953		1.4	%
Kaiser Permanente		199		4,191		1.2	%
Level 3 Communications, LLC.		197		3,765		1.1	%
Keeco, LLC.		460		2,972		0.8	%
Luminex Corporation		171		2,571		0.7	%
Wells Fargo		118		2,233		0.6	%
Salient Federal Solutions, Inc.		58		1,818		0.5	%
Welch Allyn Protocol, Inc.		103		1,655		0.5	%
Investorplace Media, LLC.		46		1,626		0.5	%
Total		2,398	$	47,245		13.4	%

 (1) For leases expiring prior to December 31, 2013, annualized rental income represents income to be received under existing leases from January 1, 2013 through the date of expiration.

Comparison of 2012 to 2011

Results of Operations: Net income for the year ended December 31, 2012 was $95.4 million compared to $102.6 million for the year ended December 31, 2011. Net income allocable to common shareholders for the year ended December 31, 2012 was $19.8 million compared to $52.2 million for the year ended December 31, 2011. Net income per common share on a diluted basis was $0.81 for the year ended December 31, 2012 compared to $2.12 for the year ended December 31, 2011 (based on weighted average diluted common shares outstanding of 24,323,000 and 24,599,000, respectively). The decrease in net income allocable to common shareholders was primarily due to the net impact of non-cash distributions and gains relating to preferred equity transactions and increases in depreciation and amortization, interest expense and preferred equity distributions, partially offset by an increase in net operating income.

In order to evaluate the performance of the Company’s portfolio over comparable periods, management analyzes the operating performance of properties owned and operated throughout both periods (herein referred to as “Same Park”). The Company defines Same Park to include all operating properties owned or acquired prior to January 1, 2010. Operating properties that the Company acquired subsequent to January 1, 2010 are referred to as “Non-Same Park.” For the year ended December 31, 2012 and 2011, the Same Park facilities constitute 19.2 million rentable square feet, representing 67.7% of the 28.3 million square feet in the Company’s portfolio as of December 31, 2012.

28

The following table presents the operating results of the Company’s properties for the years ended December 31, 2012 and 2011 in addition to other income and expense items affecting income from continuing operations (in thousands, except per square foot data):

	For The Years Ended December 31,
	2012			2011			Change
Rental income:
Same Park (19.2 million rentable square feet) (1)	$	255,086		$	256,080			(0.4	%)
Non-Same Park (9.2 million rentable square feet)		91,462			41,377			121.0	%
Total rental income		346,548			297,457			16.5	%
Cost of operations:
Same Park		82,920			83,997			(1.3	%)
Non-Same Park		31,188			15,920			95.9	%
Total cost of operations		114,108			99,917			14.2	%
Net operating income (2):
Same Park (1)		172,166			172,083			—
Non-Same Park		60,274			25,457			136.8	%
Total net operating income		232,440			197,540			17.7	%
Other income and (expenses):
Facility management fees		649			684			(5.1	%)
Interest and other income		241			221			9.0	%
Interest expense		(20,618	)		(5,455	)		278.0	%
Depreciation and amortization		(109,398	)		(84,391	)		29.6	%
General and administrative		(8,569	)		(5,969	)		43.6	%
Acquisition transaction costs		(350	)		(3,067	)		(88.6	%)
Income from continuing operations	$	94,395		$	99,563			(5.2	%)
Same Park gross margin (3)		67.3	%		66.8	%		0.7	%
Same Park weighted average occupancy		92.1	%		91.2	%		1.0	%
Non-Same Park weighted average occupancy		81.9	%		75.3	%		8.8	%
Same Park realized rent per square foot (4)	$	14.34		$	14.47			(0.9	%)

(1) See above for a definition of Same Park. Includes a lease buyout payment of $1.8 million recorded in the fourth quarter of 2012 associated with a 39,000 square foot lease in Virginia which terminated as of December 25, 2012 and a lease buyout payment of $2.9 million recorded in the third quarter of 2011 associated with a 53,000 square foot lease in Maryland which terminated as of August 31, 2011. Excluding the lease buyout payments noted above, rental income from the Same Park portfolio increased slightly, while net operating income from the Same Park portfolio increased 0.7% for the year ended December 31, 2012 over 2011.

(2) Net operating income (“NOI”) is an important measurement in the commercial real estate industry for determining the value of the real estate generating the NOI. See “Item 2. Properties” above for more information on NOI. The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance in accordance with GAAP.

(3) Same Park gross margin is computed by dividing Same Park NOI by Same Park rental income excluding the lease buyout payments recorded in 2012 and 2011 noted above.

(4) Same Park realized rent per square foot represents the Same Park rental income earned per occupied square foot excluding the lease buyout payments recorded in 2012 and 2011 noted above.

29

Supplemental Property Data and Trends: NOI from continuing operations is summarized for the years ended December 31, 2012 and 2011 by region below. See “Item 2. Properties” above for more information on NOI, including why the Company presents NOI and how the Company uses NOI. The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance calculated in accordance with GAAP.

The following table summarizes the Same Park operating results by region for the years ended December 31, 2012 and 2011. In addition, the table reflects the comparative impact on the overall rental income, cost of operations and NOI from properties that have been acquired since January 1, 2010, and the impact of such is included in Non-Same Park facilities in the table below. As part of the table below, we have reconciled total NOI to income from continuing operations (in thousands):

Region	Rental Income December  31, 2012		Rental Income December  31, 2011		Increase (Decrease)			Cost of Operations December 31, 2012		Cost of Operations December 31, 2011		Increase (Decrease)			NOI December 31, 2012			NOI December 31, 2011			Increase (Decrease)
Same Park
Northern California	$	19,498	$	19,524		(0.1	%)	$	6,371	$	6,871		(7.3	%)	$	13,127		$	12,653			3.7	%
Southern California		52,343		54,329		(3.7	%)		17,781		17,430		2.0	%		34,562			36,899			(6.3	%)
Virginia		59,570		55,112		8.1	%		16,899		17,009		(0.6	%)		42,671			38,103			12.0	%
Florida		30,756		30,407		1.1	%		9,725		9,829		(1.1	%)		21,031			20,578			2.2	%
Northern Texas		16,784		16,482		1.8	%		5,564		5,598		(0.6	%)		11,220			10,884			3.1	%
Southern Texas		8,414		7,951		5.8	%		2,967		2,668		11.2	%		5,447			5,283			3.1	%
Maryland		35,792		40,898		(12.5	%)		11,427		12,196		(6.3	%)		24,365			28,702			(15.1	%)
Washington		8,149		8,483		(3.9	%)		2,575		2,621		(1.8	%)		5,574			5,862			(4.9	%)
Oregon		18,058		17,239		4.8	%		7,062		7,041		0.3	%		10,996			10,198			7.8	%
Arizona		5,722		5,655		1.2	%		2,549		2,734		(6.8	%)		3,173			2,921			8.6	%
Total Same Park		255,086		256,080		(0.4	%)		82,920		83,997		(1.3	%)		172,166			172,083			—
Non-Same Park
Northern California		42,537		1,235		3,344.3	%		13,378		397		3,269.8	%		29,159			838			3,379.6	%
Virginia		24,652		19,747		24.8	%		9,242		8,172		13.1	%		15,410			11,575			33.1	%
Florida		785		670		17.2	%		418		344		21.5	%		367			326			12.6	%
Northern Texas		1,003		—		100.0	%		283		76		272.4	%		720			(76	)		1,047.4	%
Southern Texas		7,974		7,742		3.0	%		2,820		2,684		5.1	%		5,154			5,058			1.9	%
Maryland		13,173		11,983		9.9	%		4,372		4,247		2.9	%		8,801			7,736			13.8	%
Washington		1,338		—		100.0	%		675		—		100.0	%		663			—			100.0	%
Total Non-Same Park		91,462		41,377		121.0	%		31,188		15,920		95.9	%		60,274			25,457			136.8	%
Total	$	346,548	$	297,457		16.5	%	$	114,108	$	99,917		14.2	%	$	232,440		$	197,540			17.7	%
Reconciliation of NOI to income from  continuing operations
Total NOI															$	232,440		$	197,540			17.7	%
Other income and (expenses):
Facilities management fees																649			684			(5.1	%)
Interest and other income																241			221			9.1	%
Interest expense																(20,618	)		(5,455	)		278.0	%
Depreciation and amortization																(109,398	)		(84,391	)		29.6	%
General and administrative																(8,919	)		(9,036	)		(1.3	%)
Income from continuing operations															$	94,395		$	99,563			(5.2	%)

30

The following table summarizes Same Park weighted average occupancy rates and realized rent per square foot by region for the years ended December 31, 2012 and 2011. Realized rent per square foot for Virginia and Total Same Park excludes $1.8 million of lease buyout payment for the year ended December 31, 2012. Realized rent per square foot for Maryland and Total Same Park excludes $2.9 million of lease buyout payment for the year ended December 31, 2011.

	Weighted Average Occupancy Rates			Realized Rent Per Square Foot
Region	2012	2011	Change	2012	2011	Change
Northern California	91.4%	90.0%	1.6%	$11.73	$11.93	(1.7%)
Southern California	90.9%	89.6%	1.5%	$14.45	$15.21	(5.0%)
Virginia	93.2%	92.3%	1.0%	$20.53	$19.77	3.8%
Florida	96.4%	96.8%	(0.4%)	$8.87	$8.73	1.6%
Northern Texas	93.4%	91.8%	1.7%	$10.63	$10.62	0.1%
Southern Texas	91.8%	90.9%	1.0%	$11.65	$11.11	4.9%
Maryland	86.6%	88.5%	(2.1%)	$23.38	$24.29	(3.7%)
Washington	91.4%	93.6%	(2.4%)	$17.24	$17.40	(0.9%)
Oregon	89.2%	82.8%	7.7%	$15.41	$15.84	(2.7%)
Arizona	90.7%	89.5%	1.3%	$9.29	$9.31	(0.2%)
Total Same Park	92.1%	91.2%	1.0%	$14.34	$14.47	(0.9%)

Rental Income: Excluding the lease buyout payments noted above, rental income increased $50.2 million from $294.6 million for the year ended December 31, 2011 to $344.8 million for the year ended December 31, 2012 as a result of a $50.1 million increase in rental income from Non-Same Park facilities combined with an increase in rental income from the Same Park portfolio of $109,000 due to an increase in occupancy rates, partially offset by a decrease in rental rates. Including the lease buyout payments, rental income increased $49.1 million from $297.5 million for the year ended December 31, 2011 to $346.5 million for the year ended December 31, 2012 as a result of a $50.1 million increase in rental income from Non-Same Park facilities, partially offset by a $994,000 decrease in rental income from the Same Park portfolio.

Facility Management Fees: Facility management fees, derived from PS, account for a small portion of the Company’s net income. During the year ended December 31, 2012, $649,000 of revenue was recognized from facility management fees compared to $684,000 for the year ended December 31, 2011.

Cost of Operations: Cost of operations for the year ended December 31, 2012 was $114.1 million compared to $99.9 million for the year ended December 31, 2011, an increase of $14.2 million, or 14.2% as a result of an increase in cost of operations from Non-Same Park facilities of $15.3 million, partially offset by a $1.1 million decrease from the Same Park portfolio. The decrease in Same Park cost of operations was driven by decreases in repairs and maintenance and utility costs, partially offset by increases in payroll and benefit and insurance costs.

Depreciation and Amortization Expense: Depreciation and amortization expense was $109.4 million for the year ended December 31, 2012 compared to $84.4 million for the year ended December 31, 2011. The increase was primarily due to depreciation relating to 2011 property acquisitions.

General and Administrative Expenses: For the year ended December 31, 2012, general and administrative expenses decreased $117,000, or 1.3%, over 2011 as a result of a decrease in acquisition transactions costs due to lower volume of acquisitions. Excluding the acquisition transaction costs, general and administrative expenses increased $2.6 million, or 43.6%, compared to 2011 as a result of an increase in non-cash stock compensation expense from the amortization of a long-term incentive plan which commenced January, 2012.

Interest Expense: Interest expense was $20.6 million for the year ended December 31, 2012 compared to $5.5 million for the year ended December 31, 2011. The increase was primarily attributable to interest expense on the term loan and mortgage note assumption related to the Northern California Portfolio acquisition in December, 2011 combined with borrowings on the Credit Facility (described below).

Gain on Sale of Real Estate Facility: Included in total discontinued operations is the gain on the sale of Quail Valley Business Park, a 66,000 square foot flex park in Houston, Texas, for a gross sales price of $2.3 million, resulting in a net gain of $935,000 during October, 2012.

31

In August, 2011, the Company completed the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million.

Net Income Allocable to Noncontrolling Interests: Net income allocable to noncontrolling interests reflects the net income allocable to equity interests in the Operating Partnership that are not owned by the Company. Net income allocable to noncontrolling interests was $6.3 million of allocated income ($323,000 allocated to preferred unit holders and $6.0 million of income allocated to common unit holders) for the year ended December 31, 2012 compared to $8.6 million ($7.0 million of loss allocated to preferred unit holders and $15.5 million allocated to common unit holders) for the year ended December 31, 2011. Included in net income allocable to noncontrolling interests for the year ended December 31, 2011 was a $7.4 million loss allocated to preferred unit holders resulting from the repurchase by the Company of preferred units at an amount less than the carrying value, partially offset with $1.7 million of income allocated to common unit holders due to the net gain on the repurchases of preferred units. The decrease in net income allocable to noncontrolling interests for the year was primarily due to the net impact of non-cash distributions and gain relating to preferred equity transactions and increases in depreciation and amortization, interest expense and preferred equity distributions, partially offset by an increase in net operating income.

Comparison of 2011 to 2010

Results of Operations: Net income for the year ended December 31, 2011 was $102.6 million compared to $102.0 million for the year ended December 31, 2010. Net income allocable to common shareholders for the year ended December 31, 2011 was $52.2 million compared to $39.0 million for the year ended December 31, 2010. Net income per common share on a diluted basis was $2.12 for the year ended December 31, 2011 compared to $1.58 for the year ended December 31, 2010 (based on weighted average diluted common shares outstanding of 24,599,000 and 24,687,000, respectively). The increase in net income allocable to common shareholders was primarily a result of an increase in net operating income and lower distributions resulting from the reduction of preferred equity outstanding, partially offset by the change in gain on the sale of a real estate facility combined with increases in interest and depreciation expense primarily related to property acquisitions.

For the years ended December 31, 2011 and 2010, the Same Park facilities constitute 19.2 million rentable square feet, representing 70.8% of the 27.1 million square feet in the Company’s portfolio as of December 31, 2011.

32

The following table presents the operating results of the Company’s properties for the years ended December 31, 2011 and 2010 in addition to other income and expense items affecting income from continuing operations (in thousands, except per square foot data):

	For The Years Ended December 31,						Change
	2011			2010
Rental income:
Same Park (19.2 million rentable square feet) (1)	$	256,080		$	260,822			(1.8	%)
Non-Same Park (8.0 million rentable square feet)		41,377			15,454			167.7	%
Total rental income		297,457			276,276			7.7	%
Cost of operations:
Same Park		83,997			83,576			0.5	%
Non-Same Park		15,920			5,772			175.8	%
Total cost of operations		99,917			89,348			11.8	%
Net operating income (2):
Same Park (1)		172,083			177,246			(2.9	%)
Non-Same Park		25,457			9,682			162.9	%
Total net operating income		197,540			186,928			5.7	%
Other income and (expenses):
Facility management fees		684			672			1.8	%
Interest and other income		221			333			(33.6	%)
Interest expense		(5,455	)		(3,534	)		54.4	%
Depreciation and amortization		(84,391	)		(78,354	)		7.7	%
General and administrative		(5,969	)		(6,389	)		(6.6	%)
Acquisition transaction costs		(3,067	)		(3,262	)		(6.0	%)
Income from continuing operations	$	99,563		$	96,394			3.3	%
Same Park gross margin (3)		66.8	%		68.0	%		(1.8	%)
Same Park weighted average occupancy		91.2	%		91.6	%		(0.4	%)
Non-Same Park weighted average occupancy		75.3	%		77.9	%		(3.3	%)
Same Park realized rent per square foot (4)	$	14.47		$	14.84			(2.5	%)

(1) See above for a definition of Same Park. Include a lease buyout payment of $2.9 million recorded in the third quarter of 2011 associated with a 53,000 square foot lease in Maryland which terminated as of August 31, 2011. Excluding the $2.9 million of lease buyout payment noted above, rental income and net operating income from the Same Park portfolio decreased 2.9% and 4.5%, respectively, for the year ended December 31, 2011 over 2010.

2) Net operating income (“NOI”) is an important measurement in the commercial real estate industry for determining the value of the real estate generating the NOI. See “Item 2. Properties” above for more information on NOI. The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance in accordance with GAAP.

⁽³⁾  Same Park gross margin is computed by dividing Same Park NOI by Same Park rental income excluding the lease buyout payment recorded in 2011 noted above.

⁽⁴⁾  Same Park realized rent per square foot represents the Same Park rental income earned per occupied square foot excluding the lease buyout payment recorded in 2011 noted above.

Supplemental Property Data and Trends: NOI from continuing operations is summarized for the years ended December 31, 2011 and 2010 by region below. The Company’s calculation of NOI may not be comparable to those of other companies and should not be used as an alternative to measures of performance calculated in accordance with GAAP.

33

The following table summarizes the Same Park operating results by region for the years ended December 31, 2011 and 2010. In addition, the table reflects the comparative impact on the overall rental income, cost of operations and NOI from properties that have been acquired since January 1, 2010, and the impact of such is included in Non-Same Park facilities in the table below. As part of the table below, we have reconciled total NOI to income from continuing operations (in thousands):

Region	Rental Income December 31, 2011		Rental Income December 31, 2010		Increase (Decrease)			Cost of Operations December 31, 2011		Cost of Operations December 31, 2010		Increase (Decrease)			NOI December 31, 2011			NOI December 31, 2010		Increase (Decrease)
Same Park
Northern California	$	19,524	$	19,820		(1.5	%)	$	6,871	$	6,830		0.6	%	$	12,653		$	12,990		(2.6	%)
Southern California		54,329		58,438		(7.0	%)		17,430		17,662		(1.3	%)		36,899			40,776		(9.5	%)
Virginia		55,112		56,932		(3.2	%)		17,009		16,079		5.8	%		38,103			40,853		(6.7	%)
Florida		30,407		30,397		0.0	%		9,829		9,864		(0.4	%)		20,578			20,533		0.2	%
Northern Texas		16,482		16,664		(1.1	%)		5,598		5,720		(2.1	%)		10,884			10,944		(0.5	%)
Southern Texas		7,951		7,502		6.0	%		2,668		2,986		(10.6	%)		5,283			4,516		17.0	%
Maryland		40,898		38,843		5.3	%		12,196		12,336		(1.1	%)		28,702			26,507		8.3	%
Washington		8,483		8,290		2.3	%		2,621		2,631		(0.4	%)		5,862			5,659		3.6	%
Oregon		17,239		18,143		(5.0	%)		7,041		6,719		4.8	%		10,198			11,424		(10.7	%)
Arizona		5,655		5,793		(2.4	%)		2,734		2,749		(0.5	%)		2,921			3,044		(4.0	%)
Total Same Park		256,080		260,822		(1.8	%)		83,997		83,576		0.5	%		172,083			177,246		(2.9	%)
Non-Same Park
Northern California		1,235		—		100.0	%		397		—		100.0	%		838			—		100.0	%
Virginia		19,747		2,197		798.8	%		8,172		966		746.0	%		11,575			1,231		840.3	%
Florida		670		123		444.7	%		344		63		446.0	%		326			60		443.3	%
Northern Texas		—		—		—			76		—		100.0	%		(76	)		—		(100.0	%)
Southern Texas		7,742		4,997		54.9	%		2,684		1,882		42.6	%		5,058			3,115		62.4	%
Maryland		11,983		8,137		47.3	%		4,247		2,861		48.4	%		7,736			5,276		46.6	%
Total Non-Same Park		41,377		15,454		167.7	%		15,920		5,772		175.8	%		25,457			9,682		162.9	%
Total	$	297,457	$	276,276		7.7	%	$	99,917	$	89,348		11.8	%	$	197,540		$	186,928		5.7	%

Reconciliation of NOI to income from continuing operations
Total NOI	$	197,540		$	186,928		5.7	%
Other income and (expenses):
Facilities management fees		684			672		1.8	%
Interest and other income		221			333		(33.6	%)
Interest expense		(5,455	)		(3,534	)	54.4	%
Depreciation and amortization		(84,391	)		(78,354	)	7.7	%
General and administrative		(9,036	)		(9,651	)	(6.4	%)
Income from continuing operations	$	99,563		$	96,394		3.3	%

The following table summarizes Same Park weighted average occupancy rates and realized rent per square foot by region for the years ended December 31, 2011 and 2010. Realized rent per square foot for Maryland and Total Same Park excludes $2.9 million of lease buyout payment:

	Weighted Average Occupancy Rates For The Years Ended December  31,									Realized Rent Per Square Foot For The Years Ended December  31,
Region	2011			2010			Change			2011		2010		Change
Northern California		90.0	%		89.7	%		0.3	%	$	11.93	$	12.15		(1.8	%)
Southern California		89.6	%		92.5	%		(3.1	%)	$	15.21	$	15.85		(4.0	%)
Virginia		92.3	%		92.7	%		(0.4	%)	$	19.77	$	20.34		(2.8	%)
Florida		96.8	%		95.6	%		1.3	%	$	8.73	$	8.84		(1.2	%)
Northern Texas		91.8	%		91.8	%		—		$	10.62	$	10.74		(1.1	%)
Southern Texas		90.9	%		87.3	%		4.1	%	$	11.11	$	10.92		1.7	%
Maryland		88.5	%		91.4	%		(3.2	%)	$	24.29	$	24.03		1.1	%
Washington		93.6	%		90.4	%		3.5	%	$	17.40	$	17.60		(1.1	%)
Oregon		82.8	%		83.7	%		(1.1	%)	$	15.84	$	16.50		(4.0	%)
Arizona		89.5	%		86.7	%		3.2	%	$	9.31	$	9.84		(5.4	%)
Total Same Park		91.2	%		91.6	%		(0.4	%)	$	14.47	$	14.84		(2.5	%)

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Rental Income: Excluding the lease buyout payment noted above, rental income increased $18.3 million from $276.3 million for the year ended December 31, 2010 to $294.6 million for the year ended December 31, 2011 as a result of a $25.9 million increase in rental income from Non-Same Park facilities, partially offset by a $7.6 million decrease in rental income from the Same Park portfolio primarily due to decreases in rental and occupancy rates. Including the lease buyout payment, rental income increased $21.2 million from $276.3 million for the year ended December 31, 2010 to $297.5 million for the year ended December 31, 2011 as a result of a $25.9 million increase in rental income from Non-Same Park facilities, partially offset by a $4.7 million decrease in rental income from the Same Park portfolio.

Facility Management Fees: Facility management fees, derived from PS, account for a small portion of the Company’s net income. During the year ended December 31, 2011, $684,000 of revenue was recognized from facility management fees compared to $672,000 for the year ended December 31, 2010.

Cost of Operations: Cost of operations for the year ended December 31, 2011 was $99.9 million compared to $89.3 million for the year ended December 31, 2010, an increase of $10.6 million, or 11.8% as a result of increases in cost of operations from Non-Same Park facilities of $10.1 million and Same Park of $421,000. The increase in Same Park cost of operations was due to increases in utility costs and repairs and maintenance costs, partially offset by a decrease in payroll and benefit costs.

Depreciation and Amortization Expense: Depreciation and amortization expense was $84.4 million for the year ended December 31, 2011 compared to $78.4 million for the year ended December 31, 2010. The increase was primarily due to depreciation from 2011 and 2010 property acquisitions.

General and Administrative Expenses: For the year ended December 31, 2011, general and administrative expenses decreased $615,000, or 6.4%, over 2010 as a result of a decrease in payroll and benefit costs and a reduction in professional fees related to legal fees paid during the first quarter of 2010. Additionally, general and administrative expenses for the year ended December 31, 2011 were further reduced due to a decrease in acquisition transactions costs. The Company incurred and expensed acquisition transaction costs of $3.1 million and $3.3 million for the years ended December 31, 2011 and 2010, respectively.

Interest and Other Income: Interest and other income reflect earnings on cash balances in addition to miscellaneous income items. Interest income was $22,000 for the year ended December 31, 2011 compared to $198,000 for the year ended December 31, 2010. The decrease was primarily attributable to lower average cash balances in 2011. Average cash balances and effective interest rates for the year ended December 31, 2011 were $12.7 million and 0.2%, respectively, compared to $111.7 million and 0.2%, respectively, for the year ended December 31, 2010.

Interest Expense: Interest expense was $5.5 million for the year ended December 31, 2011 compared to $3.5 million for the year ended December 31, 2010. The increase was primarily attributable to an increase in borrowings on the Credit Facility, interest on the Term Loan and mortgage note assumption related to the Northern California Portfolio acquisition.

Gain on Sale of Real Estate Facility: Included in total discontinued operations is the gain on the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million during August, 2011.

In January, 2010, the Company completed the sale of a 131,000 square foot office building located in Houston, Texas, for a gross sales price of $10.0 million, resulting in a net gain of $5.2 million.

Net Income Allocable to Noncontrolling Interests: Net income allocable to noncontrolling interests reflects the net income allocable to equity interests in the Operating Partnership that are not owned by the Company. Net income allocable to noncontrolling interests was $8.6 million ($7.0 million of loss allocated to preferred unit holders and $15.5 million of income allocated to common unit holders) for the year ended December 31, 2011 compared to $16.7 million of allocated income ($5.1 million allocated to preferred unit holders and $11.6 million allocated to common unit holders) for the year ended December 31, 2010. Included in net income allocable to noncontrolling interests for the year ended December 31, 2011 was a $7.4 million loss allocated to preferred unit holders resulting from the repurchase by the Company of preferred units at an amount less than the carrying value, partially offset with $1.7 million of income allocated to common unit holders due to the net gain on the

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repurchases of preferred units. The decrease in net income allocable to noncontrolling interests was a result of a decrease in cash distributions as a result of the preferred equity transactions, partially offset by an increase in net operating income from Non-Same Park facilities.

Liquidity and Capital Resources

Cash and cash equivalents increased $7.9 million from $5.0 million at December 31, 2011 to $12.9 million at December 31, 2012 for the reasons noted below.

Net cash provided by operating activities for the years ended December 31, 2012 and 2011 was $209.1 million and $180.6 million, respectively. The increase of $28.5 million in net cash provided by operating activities for the year ended December 31, 2012 compared to the same period in 2011 was primarily due to an increase in net operating income of $34.9 million. Management believes that the Company’s internally generated net cash provided by operating activities will be sufficient to enable it to meet its operating expenses, capital improvements, debt service requirements and distributions to shareholders.

Net cash used in investing activities was $105.7 million and $337.1 million for the years ended December 31, 2012 and 2011, respectively. The change was primarily due to a decrease in cash paid of $246.7 million for acquisitions, partially offset by an increase in capital improvements of $8.4 million. The Company paid $51.0 million for the acquisitions in Washington and Texas in 2012 compared to $297.7 million for acquisitions in Virginia, Florida, Texas and California in 2011.

Net cash used in financing activities was $95.5 million for the year ended December 31, 2012 compared to net cash provided by financing activities of $156.4 million for the year ended December 31, 2011. The $251.9 million increase in cash used was primarily due to a decrease in borrowings of $402.0 million and an increase in debt repayment of $169.8 million as the Company repaid the balance on its Credit Facility in full, reduced the balance on its Term Loan by $50.0 million and repaid a mortgage note payable of $13.2 million, partially offset with net equity transactions of $324.6 million.

As described in Item 1, “Business — Borrowings,” the Company has a $250.0 million credit facility and a $250.0 million term loan. The Company had no balance outstanding on the credit facility at December 31, 2012. The Company had $185.0 million outstanding on the Credit Facility at an interest rate of 1.41% at December 31, 2011. The Company had $200.0 million outstanding on the Term Loan at an interest rate of 1.41% at December 31, 2012 and $250.0 million outstanding at an interest rate of 1.50% at December 31, 2011.

The Company’s preferred equity outstanding increased to 26.0% of its market capitalization during the year ended December 31, 2012 primarily due to a decrease in outstanding unsecured debt combined with the issuance of preferred stock in 2012. As of December 31, 2012, the Company had three fixed-rate mortgage notes totaling $268.1 million and an outstanding balance on the Term Loan of $200.0 million, which collectively represented 13.7% of its total market capitalization. The Company calculates market capitalization by adding (1) the liquidation preference of the Company’s outstanding preferred equity, (2) principal value of the Company’s outstanding debt and (3) the total number of common shares and common units outstanding at December 31, 2012 multiplied by the closing price of the stock on that date. The weighted average interest rate for the mortgage notes is 5.46% per annum. The Company had 23.0% of its properties, in terms of net book value, encumbered at December 31, 2012.

The Company focuses on retaining cash for reinvestment as we believe that this provides the greatest level of financial flexibility. While operating results have been negatively impacted by the slow economic conditions, we believe it is likely that as the economy recovers and operating fundamentals improve, additional increases in distributions to the Company’s common shareholders will be required. Going forward, the Company will continue to monitor its taxable income and the corresponding dividend requirements.

Issuance of Preferred Stock: On September 14, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 5.75% Cumulative Preferred Stock, Series U, at $25.00 per depositary share.

On May 14, 2012, the Company issued $350.0 million or 14.0 million depositary shares, each representing 1/1,000 of a share of the 6.00% Cumulative Preferred Stock, Series T, at $25.00 per depositary share.

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On January 18, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 6.45% Cumulative Preferred Stock, Series S, at $25.00 per depositary share.

On October 15, 2010, the Company issued $75.0 million or 3.0 million depositary shares, each representing 1/1,000 of a share of the 6.875% Cumulative Preferred Stock, Series R, at $25.00 per depositary share.

Note Payable to Affiliate: On February 9, 2011, the Company entered into an agreement with PS to borrow $121.0 million with a maturity date of August 9, 2011 at an interest rate of LIBOR plus 0.85%. The Company repaid, in full, the note payable to PS upon maturity. Interest expense under this note payable was $664,000 for the year ended December 31, 2011.

Redemption of Preferred Equity: On October 9, 2012, the Company completed the redemption of its 6.70% Cumulative Preferred Stock, Series P, at its par value of $132.3 million. The Company reported the excess of the redemption amount over the carrying amount of $3.8 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

On June 15, 2012, the Company completed the redemption of its 7.00% Cumulative Preferred Stock, Series H, at its par value of $158.5 million and its 6.875% Cumulative Preferred Stock, Series I, at its par value of $68.6 million. The Company reported the excess of the redemption amount over the carrying amount of $8.1 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

On June 8, 2012, the Company redeemed 223,300 units of its 7.125% Series N Cumulative Redeemable Preferred Units for $5.6 million. The Company reported the excess of the redemption amount over the carrying amount of $149,000, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

During February, 2012, the Company completed the redemption of its 7.20% Cumulative Preferred Stock, Series M, at its par value of $79.6 million and its 7.375% Cumulative Preferred Stock, Series O, at its par value of $84.6 million. The Company reported the excess of the redemption amount over the carrying amount of $5.3 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

On November 8, 2010, the Company completed the redemption of its 7.60% Cumulative Preferred Stock, Series L, at its aggregate par value of $48.4 million. The Company reported the excess of the redemption amount over the carrying amount of $1.6 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

On May 12, 2010, the Company completed the redemption of its 7.950% Series G Cumulative Redeemable Preferred Units at its aggregate par value of $20.0 million, and on June 7, 2010, the Company completed the redemption of its 7.950% Cumulative Preferred Stock, Series K at its aggregate par value of $54.1 million, in each case, together with accrued dividends. In connection with these redemptions, the Company reported the excess of the redemption amount over the carrying amount of $2.4 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

Repurchase of Preferred Equity: In February, 2011, the Company paid an aggregate of $39.1 million to repurchase 1,710,000 units of its 7.50% Series J Cumulative Redeemable Preferred Units and 203,400 units of its 6.55% Series Q Cumulative Redeemable Preferred Units for a weighted average purchase price of $20.43 per unit. The aggregate par value of the repurchased preferred units was $47.8 million, which generated a gain of $7.4 million, net of original issuance costs of $1.4 million, which was added to net income allocable to common shareholders and unit holders for the year ended December 31, 2011.

Repurchase of Common Stock: The Company’s Board of Directors previously authorized the repurchase, from time to time, of up to 6.5 million shares of the Company’s common stock on the open market or in privately negotiated transactions. During the year ended December 31, 2011, the Company repurchased 591,500 shares of common stock at an aggregate cost of $30.3 million or an average cost per share of $51.14. Since inception of the program, the Company has repurchased an aggregate of 4.9 million shares of common stock at an aggregate cost

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of $183.9 million or an average cost per share of $37.64. Under existing board authorizations, the Company can repurchase an additional 1.6 million shares. No shares of common stock were repurchased under this program during the years ended December 31, 2012 or 2010.

Mortgage Note Repayment: Subsequent to December 31, 2012, the Company repaid two mortgage notes payable totaling $18.1 million. In November, 2012, the Company repaid $13.2 million on a mortgage note with a stated interest rate of 5.73%.

In 2011, the Company repaid two mortgage notes payable of $18.2 million with a weighted average stated interest rate of 7.26%.

Capital Expenditures: During the years ended December 31, 2012, 2011 and 2010, the Company expended $49.9 million , $43.6 million and $28.7 million, respectively, in recurring capital expenditures, or $1.80, $1.98 and $1.40 per weighted average square foot owned, respectively. The Company defines recurring capital expenditures as those necessary to maintain and operate its commercial real estate at its current economic value. Tenant improvement amounts exclude those amounts reimbursed by the tenant. Nonrecurring capital improvements include property renovations and expenditures related to repositioning acquisitions. The following table depicts capital expenditures (in thousands):

	For the Years Ended December 31,
	2012		2011		2010
Recurring capital expenditures
Capital improvements	$	8,394	$	8,173	$	8,536
Tenant improvements		34,236		27,292		15,372
Lease commissions		7,244		8,089		4,761
Total recurring capital expenditures		49,874		43,554		28,669
Nonrecurring capital improvements		6,898		4,813		10,884
Total capital expenditures	$	56,772	$	48,367	$	39,553

Capital expenditures on a per square foot owned basis are as follows:

	For the Years Ended December 31,
	2012		2011		2010
Recurring capital expenditures
Capital improvements	$	0.30	$	0.37	$	0.42
Tenant improvements		1.24		1.24		0.75
Lease commissions		0.26		0.37		0.23
Total recurring capital expenditures		1.80		1.98		1.40
Nonrecurring capital improvements		0.25		0.22		0.53
Total capital expenditures	$	2.05	$	2.20	$	1.93

For the year ended December 31, 2012, recurring capital expenditures increased $6.3 million, or 14.5%, over the same period in 2011 primarily due to several significant tenant improvement projects within the Same Park Portfolio combined with an increase in Non-Same Park recurring capital expenditures as a result of lease up of assets.

Distributions: The Company has elected and intends to qualify as a REIT for federal income tax purposes. In order to maintain its status as a REIT, the Company must meet, among other tests, sources of income, share ownership and certain asset tests. As a REIT, the Company is not taxed on that portion of its taxable income that is distributed to its shareholders provided that at least 90% of its taxable income is distributed to its shareholders prior to the filing of its tax return.

The Company’s funding strategy has been to primarily use permanent capital, including common and preferred stock, along with internally generated retained cash flows to meet its liquidity needs. In addition, the Company may sell properties that no longer meet its investment criteria. From time to time, the Company may

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use its Credit Facility or other forms of debt to facilitate real estate acquisitions or other capital allocations. The Company targets a minimum ratio of FFO to combined fixed charges and preferred distributions of 3.0 to 1.0. Fixed charges include interest expense. Preferred distributions include amounts paid to preferred shareholders and preferred Operating Partnership unit holders. For the year ended December 31, 2012, the FFO to fixed charges and preferred distributions coverage ratio was 3.1 to 1.0, excluding the charge for the issuance costs related to the redemption of preferred equity.

Non-GAAP Supplemental Disclosure Measure: Funds from Operations: Management believes that FFO is a useful supplemental measure of the Company’s operating performance. The Company computes FFO in accordance with the White Paper on FFO approved by the Board of Governors of NAREIT. The White Paper defines FFO as net income, computed in accordance with GAAP, before depreciation, amortization, gains or losses on asset dispositions, net income allocable to noncontrolling interests — common units, net income allocable to restricted stock unit holders, impairment charges and nonrecurring items. Management believes that FFO provides a useful measure of the Company’s operating performance and when compared year over year, reflects the impact to operations from trends in occupancy rates, rental rates, operating costs, development activities, general and administrative expenses and interest costs, providing a perspective not immediately apparent from net income.

FFO should be analyzed in conjunction with net income. However, FFO should not be viewed as a substitute for net income as a measure of operating performance or liquidity as it does not reflect depreciation and amortization costs or the level of capital expenditure and leasing costs necessary to maintain the operating performance of the Company’s properties, which are significant economic costs and could materially affect the Company’s results of operations.

Management believes FFO provides useful information to the investment community about the Company’s operating performance when compared to the performance of other real estate companies as FFO is generally recognized as the industry standard for reporting operations of REITs. Other REITs may use different methods for calculating FFO and, accordingly, our FFO may not be comparable to other real estate companies.

FFO for the Company is computed as follows (in thousands):

	For The Years Ended December 31,
	2012			2011			2010			2009			2008
Net income allocable to common shareholders	$	19,805		$	52,162		$	38,959		$	59,413		$	23,179
Gain on sale of land and real estate facility		(935	)		(2,717	)		(5,153	)		(1,488	)		—
Depreciation and amortization(1)		109,494			84,682			78,868			85,094			99,848
Net income allocable to noncontrolling interests — common units		5,970			15,543			11,594			19,730			8,296
Net income allocable to restricted stock unit holders		138			127			152			325			235
Consolidated FFO allocable to common and dilutive shares		134,472			149,797			124,420			163,074			131,558
FFO allocated to noncontrolling interests — common units		(31,041	)		(34,319	)		(28,450	)		(40,472	)		(34,443	)
FFO allocated to restricted stock unit holders		(455	)		(301	)		(374	)		(726	)		(730	)
FFO allocated to common shares	$	102,976		$	115,177		$	95,596		$	121,876		$	96,385

 (1) Includes depreciation from discontinued operations.

FFO allocable to common and dilutive shares decreased $15.3 million for the year ended December 31, 2012, respectively, compared to the same periods in 2011. The decrease was primarily due to the net impact of preferred equity transactions (noted above) and increases in interest expense, preferred equity distributions, partially offset by an increase in net operating income.

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Related Party Transactions: At December 31, 2012, PS owned 23.9% of the outstanding shares of the Company’s common stock and 23.1% of the outstanding common units of the Operating Partnership (100.0% of the common units not owned by the Company). Assuming issuance of the Company’s common stock upon redemption of its partnership units, PS would own 41.5% of the outstanding shares of the Company’s common stock. Ronald L. Havner, Jr., the Company’s chairman, is also the Chairman of the Board, Chief Executive Officer and President of PS. Gary E. Pruitt, an independent director of the Company is also a trustee of PS.

Pursuant to a cost sharing and administrative services agreement, the Company shares costs with PS for certain administrative services. These costs totaled $441,000 in 2012, which were allocated to PS in accordance with a methodology intended to fairly allocate those costs. In addition, the Company provides property management services for properties owned by PS for a management fee of 5% of the gross revenues of such properties in addition to reimbursement of direct costs. These management fee revenues recognized under management contract with PS totaled $649,000 in 2012. PS also provides property management services for the self-storage component of two assets owned by the Company for a fee of 6% of the gross revenues of such properties in addition to reimbursement of certain costs. Management fee expense recognized under the management contract with PS totaled $55,000 for the year ended December 31, 2012.

On February 9, 2011, the Company entered into an agreement with PS to borrow $121.0 million with a maturity date of August 9, 2011 at an interest rate of LIBOR plus 0.85%. The Company repaid, in full, the note payable to PS upon maturity. Interest expense under this note payable was $664,000 for the year ended December 31, 2011.

The PS Business Parks name and logo is owned by PS and licensed to the Company under a non-exclusive, royalty-free license agreement. The license can be terminated by either party for any reason with six-months written notice.

Off-Balance Sheet Arrangements: The Company does not have any off-balance sheet arrangements.

Contractual Obligations: The table below summarizes projected payments due under our contractual obligations as of December 31, 2012 (in thousands):

	Payments Due by Period
Contractual Obligations	Total		Less than 1 year		1 - 3 years		3 - 5 years		More than 5 years
Mortgage notes payable (principal and interest)	$	321,902	$	32,151	$	27,258	$	262,493	$	—
Credit Facility (principal)		—		—		—		—		—
Term Loan (principal)		200,000		—		200,000		—		—
Total	$	521,902	$	32,151	$	227,258	$	262,493	$	—

Company is scheduled to pay cash dividends of $54.2 million per year on its preferred equity outstanding as of December 31, 2012. Dividends are paid when and if declared by the Company’s Board of Directors and accumulate if not paid. Shares and units of preferred equity are redeemable by the Company in order to preserve its status as a REIT and are also redeemable five years after issuance.

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

To limit the Company’s exposure to market risk, the Company principally finances its operations and growth with permanent equity capital consisting of either common or preferred stock. The Company, from time to time, will use debt financing to facilitate acquisitions. In connection with the Northern California Portfolio acquisition, the Company assumed a $250.0 million mortgage note and obtained a $250.0 million term loan. As a result of the acquisition, the Company’s debt as a percentage of total equity (based on book values) was 29.0% as of December 31, 2012.

The Company’s market risk sensitive instruments include mortgage notes of $268.1 million and the outstanding balance on the Term Loan of $200.0 million as of December 31, 2012. All of the Company’s mortgage notes bear interest at fixed rates with a weighted average fixed rate of 5.46% at December 31, 2012. The Term Loan bears interest at variable rates which is currently LIBOR plus 1.20%. See Notes 2, 5 and 6 to

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consolidated financial statements for terms, valuations and approximate principal maturities of the mortgage notes payable, Credit Facility and Term Loan as of December 31, 2012. Based on borrowing rates currently available to the Company, the difference between the carrying amount of debt and its fair value is insignificant.

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

The financial statements of the Company at December 31, 2012 and 2011 and for the years ended December 31, 2012, 2011 and 2010 and the report of Ernst & Young LLP, Independent Registered Public Accounting Firm, thereon and the related financial statement schedule, are included elsewhere herein. Reference is made to the Index to Consolidated Financial Statements and Schedules in Item 15.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

Not Applicable.

ITEM 9A. CONTROLS AND PROCEDURES

Conclusion Regarding the Effectiveness of Disclosure Controls and Procedures

The Company’s management, with the participation of the Company’s Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of the Company’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) as of December 31, 2012. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of the Company’s disclosure controls and procedures as of December 31, 2012, the Company’s Chief Executive Officer and Chief Financial Officer concluded that, as of such date, the Company’s disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act. Under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting based on the framework in Internal Control-Integrated Framework issued by the Committee on Sponsoring Organizations of the Treadway Commission. Based on our evaluation under the framework in Internal Control-Integrated Framework, our management concluded that our internal control over financial reporting was effective as of December 31, 2012.

The effectiveness of the Company’s internal control over financial reporting as of December 31, 2012 has been audited by Ernst & Young LLP, an independent registered public accounting firm, as stated in their report which is included herein.

Changes in Internal Control Over Financial Reporting

There have not been any changes in our internal control over financial reporting (as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) during the fourth quarter of 2012 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Shareholders of

PS Business Parks, Inc.

We have audited PS Business Parks, Inc. internal control over financial reporting as of December 31, 2012, based on criteria established in Internal Control — Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (the COSO criteria). PS Business Parks, Inc. management is responsible for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the Company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the Company are being made only in accordance with authorizations of management and directors of the Company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the Company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, PS Business Parks, Inc. maintained, in all material respects, effective internal control over financial reporting as of December 31, 2012, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated balance sheets of PS Business Parks, Inc. as of December 31, 2012 and 2011, and the related consolidated statements of income, shareholders’ equity, and cash flows for each of the three years in the period ended December 31, 2012 and our report dated February 22, 2013 expressed an unqualified opinion thereon.

/s/    Ernst & Young LLP

Los Angeles, California

February 22, 2013

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ITEM 9B. OTHER INFORMATION

None.

PART III

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

The information required by this item with respect to directors is hereby incorporated by reference to the material appearing in the Company’s definitive proxy statement to be filed in connection with the annual shareholders’ meeting to be held in 2013 (the “Proxy Statement”) under the caption “Election of Directors.”

The following is a biographical summary of the executive officers of the Company:

Joseph D. Russell, Jr., age 53, has been President since September, 2002 and was named Chief Executive Officer and elected as a Director in August, 2003. Mr. Russell joined Spieker Partners in 1990 and became an officer of Spieker Properties when it went public as a REIT in 1993. Prior to its merger with Equity Office Properties (“EOP”) in 2001, Mr. Russell was President of Spieker Properties’ Silicon Valley Region from 1999 to 2001. Mr. Russell earned a Bachelor of Science degree from the University of Southern California and a Masters of Business Administration from the Harvard Business School. Prior to entering the commercial real estate business, Mr. Russell spent approximately six years with IBM in various marketing positions. Mr. Russell has been a member and past President of the National Association of Industrial and Office Parks, Silicon Valley Chapter. Mr. Russell is also a member of the Board of Governors of NAREIT.

John W. Petersen, age 49, has been Executive Vice President and Chief Operating Officer since he joined the Company in December, 2004. Prior to joining the Company, Mr. Petersen was Senior Vice President, San Jose Region, for Equity Office Properties from July, 2001 to December, 2004, responsible for 11.3 million square feet of multi-tenant office, industrial and R&D space in Silicon Valley. Prior to EOP, Mr. Petersen was Senior Vice President with Spieker Properties, from 1995 to 2001 overseeing the growth of that company’s portfolio in San Jose, through acquisition and development of nearly three million square feet. Mr. Petersen is a graduate of The Colorado College in Colorado Springs, Colorado, and was recently the President of National Association of Industrial and Office Parks, Silicon Valley Chapter.

Edward A. Stokx, age 47, a certified public accountant, has been Chief Financial Officer and Secretary of the Company since December, 2003 and Executive Vice President since March, 2004. Mr. Stokx has overall responsibility for the Company’s finance and accounting functions. In addition, he has responsibility for executing the Company’s financial initiatives. Mr. Stokx joined Center Trust, a developer, owner, and operator of retail shopping centers in 1997. Prior to his promotion to Chief Financial Officer and Secretary in 2001, he served as Senior Vice President, Finance and Controller. After Center Trust’s merger in January, 2003 with another public REIT, Mr. Stokx provided consulting services to various entities. Prior to joining Center Trust, Mr. Stokx was with Deloitte and Touche from 1989 to 1997, with a focus on real estate clients. Mr. Stokx earned a Bachelor of Science degree in Accounting from Loyola Marymount University.

Maria R. Hawthorne, age 53, was promoted to Executive Vice President, East Coast of the Company in February, 2011. Ms. Hawthorne served as Senior Vice President from March, 2004 to February, 2011, with responsibility for property operations on the East Coast, which includes Virginia, Maryland and Florida. From June, 2001 through March, 2004, Ms. Hawthorne was Vice President of the Company, responsible for property operations in Virginia. From July, 1994 to June, 2001, Ms. Hawthorne was a Regional Manager of the Company in Virginia. From August, 1988 to July, 1994, Ms. Hawthorne was a General Manager, Leasing Director and Property Manager for American Office Park Properties. Ms. Hawthorne earned a Bachelor of Arts Degree in International Relations from Pomona College.

Information required by this item with respect to the nominating process, the audit committee and the audit committee financial expert is hereby incorporated by reference to the material appearing in the Proxy Statement under the caption “Corporate Governance and Board Matters.”

43

Information required by this item with respect to a code of ethics is hereby incorporated by reference to the material appearing in the Proxy Statement under the caption “Corporate Governance and Board Matters.” We have adopted a code of ethics that applies to our principal executive officer, principal financial officer and principal accounting officer, which is available on our website at www.psbusinessparks.com. The information contained on the Company’s website is not a part of, or incorporated by reference into, this Annual Report on Form 10-K. Any amendments to or waivers of the code of ethics granted to the Company’s executive officers or the controller will be published promptly on our website or by other appropriate means in accordance with SEC rules.

Information required by this item with respect to the compliance with Section 16(a) is hereby incorporated by reference to the material appearing in the Proxy Statement under the caption “Section 16(a) Beneficial Ownership Reporting Compliance.”

ITEM 11. EXECUTIVE COMPENSATION

The information required by this item is hereby incorporated by reference to the material appearing in the Proxy Statement under the captions “Corporate Governance and Board Matters,” “Executive Compensation,” “Corporate Governance and Board Matters — Compensation Committee Interlocks and Insider Participation” and “Report of the Compensation Committee.”

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

The information required by this item with respect to security ownership of certain beneficial owners and management is hereby incorporated by reference to the material appearing in the Proxy Statement under the captions “Stock Ownership of Certain Beneficial Owners and Management.”

The following table sets forth information as of December 31, 2012 on the Company’s equity compensation plans:

Plan Category	(a) Number of Securities to be Issued Upon Exercise of Outstanding Options, Warrants, and Rights			(b) Weighted - Average Exercise Price of Outstanding Options, Warrants, and Rights			(c) Number of  Securities Remaining Available for Future Issuance under Equity Compensation Plans (Excluding Securities Reflected in Column (a))
Equity compensation plans approved by security holders		507,663		$	53.65			975,040
Equity compensation plans not approved by security holders		—		$	—			—
Total		507,663	*	$	53.65	*		975,040	*

* Amounts include restricted stock units.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The information required by this item is hereby incorporated by reference to the material appearing in the Proxy Statement under the captions “Corporate Governance and Board Matters” and “Certain Relationships and Related Transactions.”

ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES

The information required by this item is hereby incorporated by reference to the material appearing in the Proxy Statement under the captions “Ratification of Independent Registered Public Accountants.”

44

PART IV

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

a. 1. Financial Statements

The financial statements listed in the accompanying Index to Consolidated Financial Statements and Schedules are filed as part of this report.

2. Financial Statements Schedule

The financial statements schedule listed in the accompanying Index to Consolidated Financial Statements and Schedules are filed as part of this report.

3. Exhibits

The exhibits listed in the Exhibit Index immediately preceding such exhibits are filed with or incorporated by reference in this report.

b. Exhibits

The exhibits listed in the Exhibit Index immediately preceding such exhibits are filed with or incorporated by reference in this report.

c. Financial Statement Schedules

Not applicable.

45

PS BUSINESS PARKS, INC.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS AND SCHEDULES

(Item 15(a)(1) and Item 15(a)(2))

	Page
Report of Independent Registered Public Accounting Firm		47
Consolidated balance sheets as of December 31, 2012 and 2011		48
Consolidated statements of income for the years ended December 31, 2012, 2011 and 2010		49
Consolidated statements of equity for the years ended December 31, 2012, 2011 and 2010		50
Consolidated statements of cash flows for the years ended December 31, 2012, 2011 and 2010		51
Notes to consolidated financial statements		53
Schedule:
III — Real estate and accumulated depreciation		72

All other schedules have been omitted since the required information is not present or not present in amounts sufficient to require submission of the schedule, or because the information required is included in the consolidated financial statements or notes thereto.

46

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors and Shareholders of

PS Business Parks, Inc.

We have audited the accompanying consolidated balance sheets of PS Business Parks, Inc. as of December 31, 2012 and 2011, and the related consolidated statements of income, shareholders’ equity and cash flows for each of the three years in the period ended December 31, 2012. Our audits also included the financial statement schedule listed in the Index at Item 15(a). These financial statements and financial statement schedule are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements and financial statement schedule based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the consolidated financial position of PS Business Parks, Inc. at December 31, 2012 and 2011, and the consolidated results of its operations and its cash flows for each of the three years in the period ended December 31, 2012, in conformity with U.S. generally accepted accounting principles. Also, in our opinion, the related financial statement schedule, when considered in relation to the basic financial statements taken as a whole, presents fairly in all material respects the information set forth therein.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), PS Business Parks, Inc.’s internal control over financial reporting as of December 31, 2012, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 22, 2013 expressed an unqualified opinion thereon.

/s/    Ernst & Young LLP

Los Angeles, California

February 22, 2013

47

PS BUSINESS PARKS, INC.

CONSOLIDATED BALANCE SHEETS

	December 31,
	2012			2011
	(In thousands, except share data)
ASSETS
Cash and cash equivalents	$	12,883		$	4,980
Real estate facilities, at cost:
Land		793,352			772,573
Buildings and improvements		2,235,448			2,155,772
		3,028,800			2,928,345
Accumulated depreciation		(942,639	)		(845,700	)
		2,086,161			2,082,645
Properties held for disposition, net		—			1,218
Land held for development		6,829			6,829
		2,092,990			2,090,692
Rent receivable		4,754			3,198
Deferred rent receivable		25,329			23,388
Other assets		15,861			16,361
Total assets	$	2,151,817		$	2,138,619
LIABILITIES AND EQUITY
Accrued and other liabilities	$	69,454		$	60,940
Credit facility		—			185,000
Term loan		200,000			250,000
Mortgage notes payable		268,102			282,084
Total liabilities		537,556			778,024
Commitments and contingencies
Equity:
PS Business Parks, Inc.’s shareholders’ equity:
Preferred stock, $0.01 par value, 50,000,000 shares authorized, 35,400 and 23,942 shares issued and outstanding at December 31, 2012 and 2011, respectively		885,000			598,546
Common stock, $0.01 par value, 100,000,000 shares authorized, 24,298,475 and 24,128,184 shares issued and outstanding at December 31, 2012 and 2011, respectively		242			240
Paid-in capital		537,091			534,322
Cumulative net income		967,783			878,704
Cumulative distributions		(944,427	)		(832,607	)
Total PS Business Parks, Inc.’s shareholders’ equity		1,445,689			1,179,205
Noncontrolling interests:
Preferred units		—			5,583
Common units		168,572			175,807
Total noncontrolling interests		168,572			181,390
Total equity		1,614,261			1,360,595
Total liabilities and equity	$	2,151,817		$	2,138,619

See accompanying notes.

48

PS BUSINESS PARKS, INC.

CONSOLIDATED STATEMENTS OF INCOME

	For The Years Ended December 31,
	2012			2011			2010
	(In thousands, except per share data)
Revenues:
Rental income	$	346,548		$	297,457		$	276,276
Facility management fees		649			684			672
Total operating revenues		347,197			298,141			276,948
Expenses:
Cost of operations		114,108			99,917			89,348
Depreciation and amortization		109,398			84,391			78,354
General and administrative		8,919			9,036			9,651
Total operating expenses		232,425			193,344			177,353
Other income and (expenses):
Interest and other income		241			221			333
Interest expense		(20,618	)		(5,455	)		(3,534	)
Total other income and (expenses)		(20,377	)		(5,234	)		(3,201	)
Income from continuing operations		94,395			99,563			96,394
Discontinued operations:
Income from discontinued operations		42			360			475
Gain on sale of real estate facilities		935			2,717			5,153
Total discontinued operations		977			3,077			5,628
Net income	$	95,372		$	102,640		$	102,022
Net income allocation:
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units	$	5,970		$	15,543		$	11,594
Noncontrolling interests — preferred units		323			(6,991	)		5,103
Total net income allocable to noncontrolling interests		6,293			8,552			16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders		69,136			41,799			46,214
Restricted stock unit holders		138			127			152
Common shareholders		19,805			52,162			38,959
Total net income allocable to PS Business Parks, Inc.		89,079			94,088			85,325
Net income	$	95,372		$	102,640		$	102,022
Net income per common share — basic:
Continuing operations	$	0.79		$	2.03		$	1.41
Discontinued operations	$	0.03		$	0.10		$	0.18
Net income	$	0.82		$	2.13		$	1.59
Net income per common share — diluted:
Continuing operations	$	0.78		$	2.02		$	1.40
Discontinued operations	$	0.03		$	0.10		$	0.18
Net income	$	0.81		$	2.12		$	1.58
Weighted average common shares outstanding:
Basic		24,234			24,516			24,546
Diluted		24,323			24,599			24,687

See accompanying notes.

49

PS BUSINESS PARKS, INC.

CONSOLIDATED STATEMENTS OF EQUITY

	Preferred Stock						Common Stock						Paid-in Capital			Cumulative Net Income		Cumulative Distributions			Total PS Business Parks, Inc.’s Shareholders’ Equity			Noncontrolling Interests			Total Equity
	Shares			Amount			Shares			Amount
	(In thousands, except share data)
Balances at December 31, 2009		25,042		$	626,046			24,399,509		$	243		$	548,393		$	699,291	$	(658,294	)	$	1,215,679		$	249,958		$	1,465,637
Issuance of preferred stock, net of issuance costs		3,000			75,000			—			—			(2,487	)		—		—			72,513			—			72,513
Redemption of preferred stock, net of issuance costs		(4,100	)		(102,500	)		—			—			3,484			—		(3,484	)		(102,500	)		—			(102,500	)
Redemption of preferred units, net of issuance costs		—			—			—			—			582			—		—			582			(20,582	)		(20,000	)
Exercise of stock options		—			—			243,936			3			7,780			—		—			7,783			—			7,783
Stock compensation, net		—			—			27,732			—			1,031			—		—			1,031			—			1,031
Net income		—			—			—			—			—			85,325		—			85,325			16,697			102,022
Distributions:
Preferred stock		—			—			—			—			—			—		(42,730	)		(42,730	)		—			(42,730	)
Common stock		—			—			—			—			—			—		(43,254	)		(43,254	)		—			(43,254	)
Noncontrolling interests		—			—			—			—			—			—		—			—			(17,377	)		(17,377	)
Adjustment to noncontrolling interests in underlying operating partnership		—			—			—			—			(901	)		—		—			(901	)		901			—
Balances at December 31, 2010		23,942			598,546			24,671,177			246			557,882			784,616		(747,762	)		1,193,528			229,597			1,423,125
Repurchase of preferred units, net of issuance costs		—			—			—			—			10,107			—		—			10,107			(49,194	)		(39,087	)
Repurchase of common stock		—			—			(591,500	)		(6	)		(30,246	)		—		—			(30,252	)		—			(30,252	)
Exercise of stock options		—			—			24,600			—			1,050			—		—			1,050			—			1,050
Stock compensation, net		—			—			23,907			—			1,218			—		—			1,218			—			1,218
Net income		—			—			—			—			—			94,088		—			94,088			8,552			102,640
Distributions:
Preferred stock		—			—			—			—			—			—		(41,799	)		(41,799	)		—			(41,799	)
Common stock		—			—			—			—			—			—		(43,046	)		(43,046	)		—			(43,046	)
Noncontrolling interests		—			—			—			—			—			—		—			—			(13,254	)		(13,254	)
Adjustment to noncontrolling interests in underlying operating partnership		—			—			—			—			(5,689	)		—		—			(5,689	)		5,689			—
Balances at December 31, 2011		23,942			598,546			24,128,184			240			534,322			878,704		(832,607	)		1,179,205			181,390			1,360,595
Issuance of preferred stock, net of issuance costs		32,400			810,000			—			—			(25,608	)		—		—			784,392			—			784,392
Redemption of preferred stock, net of issuance costs		(20,942	)		(523,546	)		—			—			17,167			—		(17,167	)		(523,546	)		—			(523,546	)
Redemption of preferred units, net of issuance costs		—			—			—			—			149			—		—			149			(5,732	)		(5,583	)
Exercise of stock options		—			—			143,043			2			5,905			—		—			5,907			—			5,907
Stock compensation, net		—			—			27,248			—			4,807			—		—			4,807			—			4,807
Net income		—			—			—			—			—			89,079		—			89,079			6,293			95,372
Distributions:
Preferred stock		—			—			—			—			—			—		(51,969	)		(51,969	)		—			(51,969	)
Common stock		—			—			—			—			—			—		(42,684	)		(42,684	)		—			(42,684	)
Noncontrolling interests		—			—			—			—			—			—		—			—			(13,030	)		(13,030	)
Adjustment to noncontrolling interests in underlying operating partnership		—			—			—			—			349			—		—			349			(349	)		—
Balances at December 31, 2012		35,400		$	885,000			24,298,475		$	242		$	537,091		$	967,783	$	(944,427	)	$	1,445,689		$	168,572		$	1,614,261

See accompanying notes.

50

PS BUSINESS PARKS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

	For The Years Ended December 31,
	2012			2011			2010
	(In thousands)
Cash flows from operating activities:
Net income	$	95,372		$	102,640		$	102,022
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense		109,494			84,682			78,868
In-place lease adjustment		501			843			571
Tenant improvement reimbursements net of lease incentives		(1,315	)		(769	)		(603	)
Amortization of mortgage note premium		—			(215	)		(285	)
Gain on sale of real estate facilies		(935	)		(2,717	)		(5,153	)
Stock compensation		5,434			1,965			2,116
Increase in receivables and other assets		(5,025	)		(3,074	)		(2,809	)
Increase (decrease) in accrued and other liabilities		5,601			(2,735	)		2,389
Total adjustments		113,755			77,980			75,094
Net cash provided by operating activities		209,127			180,620			177,116
Cash flows from investing activities:
Capital improvements to real estate facilities		(56,772	)		(48,367	)		(39,553	)
Acquisition of real estate facilities		(51,022	)		(297,738	)		(296,251	)
Proceeds from sale of real estate facilities		2,065			8,999			9,181
Net cash used in investing activities		(105,729	)		(337,106	)		(326,623	)
Cash flows from financing activities:
Borrowings on credit facility		154,000			185,000			93,000
Borrowings on term loan		—			250,000			—
Note payable to affiliate		—			121,000			—
Repayment of borrowings on credit facility		(339,000	)		(93,000	)		—
Repayment of borrowings on term loan debt		(50,000	)		—			—
Repayment of note payable to affiliate		—			(121,000	)		—
Principal payments on mortgage notes payable		(828	)		(1,032	)		(1,091	)
Repayment of mortgage note payable		(13,154	)		(18,180	)		—
Net proceeds from the issuance of preferred stock		784,392			—			72,513
Proceeds from the exercise of stock options		5,907			1,050			7,783
Redemption/repurchase of preferred stock		(523,546	)		—			(102,500	)
Redemption/repurchase of preferred units		(5,583	)		(39,087	)		(20,000	)
Repurchase of common stock		—			(30,252	)		—
Distributions paid to preferred shareholders		(51,969	)		(41,799	)		(42,730	)
Distributions paid to noncontrolling interests — common units		(12,856	)		(12,856	)		(12,856	)
Distributions paid to noncontrolling interests — preferred units		(174	)		(398	)		(4,521	)
Distributions paid to common shareholders		(42,684	)		(43,046	)		(43,254	)
Net cash (used in) provided by financing activities		(95,495	)		156,400			(53,656	)
Net increase (decrease) in cash and cash equivalents		7,903			(86	)		(203,163	)
Cash and cash equivalents at the beginning of the year		4,980			5,066			208,229
Cash and cash equivalents at the end of the year	$	12,883		$	4,980		$	5,066
Supplemental disclosures:
Interest paid	$	18,872		$	5,041		$	3,547

See accompanying notes.

51

PS BUSINESS PARKS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

	For The Years Ended December 31,
	2012			2011			2010
	(In thousands)
Supplemental schedule of non-cash investing and financing activities:
Adjustment to noncontrolling interests in underlying operating partnership:
Noncontrolling interests — common units	$	(349	)	$	5,689		$	901
Paid-in capital	$	349		$	(5,689	)	$	(901	)
Gain on repurchase of preferred equity:
Preferred units	$	—		$	(8,748	)	$	—
Paid-in capital	$	—		$	8,748		$	—
Issuance costs related to the redemption/repurchase of preferred equity:
Cumulative distributions	$	(17,167	)	$	—		$	(3,484	)
Noncontrolling interest — common units	$	(149	)	$	(1,359	)	$	(582	)
Paid-in capital	$	17,316		$	1,359		$	4,066
Mortgage note assumed in property acquisition:
Real estate facilities	$	—		$	(250,000	)	$	—
Mortgage notes payable	$	—		$	250,000		$	—

52

PS BUSINESS PARKS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

DECEMBER 31, 2012

1. Organization and description of business

Organization

PS Business Parks, Inc. (“PSB”) was incorporated in the state of California in 1990. As of December 31, 2012, PSB owned 76.9% of the common partnership units of PS Business Parks, L.P. (the “Operating Partnership”). The remaining common partnership units are owned by Public Storage (“PS”). PSB, as the sole general partner of the Operating Partnership, has full, exclusive and complete responsibility and discretion in managing and controlling the Operating Partnership. PSB and the Operating Partnership are collectively referred to as the “Company.”

Description of business

The Company is a fully-integrated, self-advised and self-managed real estate investment trust (“REIT”) that owns, operates, acquires and develops commercial properties, primarily multi-tenant flex, office and industrial space. As of December 31, 2012, the Company owned and operated 28.3 million rentable square feet of commercial space located in eight states. The Company also manages 1.2 million rentable square feet on behalf of PS.

References to the number of properties or square footage are unaudited and outside the scope of the Company’s independent registered public accounting firm’s audit of the Company’s financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States).

2. Summary of significant accounting policies

Basis of presentation

The accompanying consolidated financial statements include the accounts of PSB and the Operating Partnership. All significant inter-company balances and transactions have been eliminated in the consolidated financial statements.

Noncontrolling Interests

The Company’s noncontrolling interests are reported as a component of equity separate from the parent’s equity. Purchases or sales of equity interests that do not result in a change in control are accounted for as equity transactions. In addition, net income attributable to the noncontrolling interest is included in consolidated net income on the face of the income statement and, upon a gain or loss of control, the interest purchased or sold, as well as any interest retained, is recorded at fair value with any gain or loss recognized in earnings.

Use of estimates

The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates.

Allowance for doubtful accounts

The Company monitors the collectability of its receivable balances including the deferred rent receivable on an ongoing basis. Based on these reviews, the Company maintains an allowance for doubtful accounts for estimated losses resulting from the possible inability of tenants to make contractual rent payments to the Company. A provision for doubtful accounts is recorded during each period. The allowance for doubtful

53

accounts, which represents the cumulative allowances less write-offs of uncollectible rent, is netted against tenant and other receivables on the consolidated balance sheets. Tenant receivables are net of an allowance for uncollectible accounts totaling $400,000 at December 31, 2012 and 2011.

Financial instruments

The methods and assumptions used to estimate the fair value of financial instruments are described below. The Company has estimated the fair value of financial instruments using available market information and appropriate valuation methodologies. Considerable judgment is required in interpreting market data to develop estimates of market value. Accordingly, estimated fair values are not necessarily indicative of the amounts that could be realized in current market exchanges. The Company determines the estimated fair value of financial assets and liabilities utilizing a hierarchy of valuation techniques based on whether the inputs to a fair value measurement are considered to be observable or unobservable in a marketplace. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions. This hierarchy requires the use of observable market data when available. The following is the fair value hierarchy:

• Level 1—quoted prices for identical instruments in active markets

• Level 2—quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which significant inputs and significant value drivers are observable in active markets; and

• Level 3—fair value measurements derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable

Financial assets that are exposed to credit risk consist primarily of cash and cash equivalents and receivables. The Company considers all highly liquid investments with a remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents, which consist primarily of money market investments, are only invested in entities with an investment grade rating. Receivables are comprised of balances due from a large number of customers. Balances that the Company expects to become uncollectible are reserved for or written off. Due to the short period to maturity of the Company’s cash and cash equivalents, accounts receivable, other assets and accrued and other liabilities, the carrying values as presented on the consolidated balance sheets are reasonable estimates of fair value.

Carrying values of the Company’s mortgage notes payable, unsecured credit facility and term loan are deemed to approximate fair value. The characteristics of these financial instruments, market data and other comparative metrics utilized in determining these fair values are “Level 2” inputs.

Real estate facilities

Real estate facilities are recorded at cost. Costs related to the renovation or improvement of the properties are capitalized. Expenditures for repairs and maintenance are expensed as incurred. Expenditures that are expected to benefit a period greater than two years and exceed $2,000 are capitalized and depreciated over their estimated useful life. Buildings and improvements are depreciated using the straight-line method over their estimated useful lives, which generally range from five to 30 years. Transaction costs, which include tenant improvements and lease commissions, in excess of $1,000 for leases with terms greater than one year are capitalized and depreciated over their estimated useful lives. Transaction costs less than $1,000 or leases of one year or less are expensed as incurred.

Properties held for disposition

An asset is classified as an asset held for disposition when it meets certain requirements, which include, among other criteria, the approval of the sale of the asset, the marketing of the asset for sale and the expectation by the Company that the sale will likely occur within the next 12 months. Upon classification of an asset as held for disposition, depreciation of the asset is ceased, the operating results of the asset are included in discontinued operations for all periods presented and the net book value of the asset is included on the balance sheet as properties held for disposition.

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Intangible assets/liabilities

Intangible assets and liabilities include above-market and below-market in-place lease values of acquired properties based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) management’s estimate of fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. The capitalized above-market and below-market lease values (included in other assets and accrued liabilities in the accompanying consolidated balance sheets) are amortized to rental income over the remaining non-cancelable terms of the respective leases. The Company recorded net amortization reducing rental income of $501,000, $843,000 and $571,000 of intangible assets and liabilities resulting from the above-market and below-market lease values during the years ended December 31, 2012, 2011 and 2010, respectively. As of December 31, 2012, the value of in-place leases resulted in a net intangible asset of $5.2 million, net of $4.7 million of accumulated amortization with a weighted average amortization period of 6.4 years, and a net intangible liability of $4.7 million, net of $3.0 million of accumulated amortization with a weighted average amortization period of 5.0 years. As of December 31, 2011, the value of in-place leases resulted in a net intangible asset of $6.9 million, net of $2.3 million of accumulated amortization and a net intangible liability of $6.4 million, net of $1.1 million of accumulated amortization.

Evaluation of asset impairment

The Company evaluates its assets used in operations for impairment by identifying indicators of impairment and by comparing the sum of the estimated undiscounted future cash flows for each asset to the asset’s carrying value. When indicators of impairment are present and the sum of the estimated undiscounted future cash flows is less than the carrying value of such asset, an impairment loss is recorded equal to the difference between the asset’s current carrying value and its value based on discounting its estimated future cash flows. In addition, the Company evaluates its assets held for disposition for impairment. Assets held for disposition are reported at the lower of their carrying value or fair value, less cost of disposition. At December 31, 2012, the Company did not consider any assets to be impaired.

Asset impairment due to casualty loss

It is the Company’s policy to record as a casualty loss or gain, in the period the casualty occurs, the differential between (a) the book value of assets destroyed and (b) any insurance proceeds that the Company expects to receive in accordance with its insurance contracts. Potential proceeds from insurance that are subject to any uncertainties, such as interpretation of deductible provisions of the governing agreements, the estimation of costs of restoration, or other such items, are treated as contingent proceeds and not recorded until the uncertainties are satisfied.

For the years ended December 31, 2012, 2011 and 2010 no material casualty losses were incurred.

Stock compensation

All share-based payments to employees, including grants of employee stock options, are recognized as stock compensation in the Company’s income statement based on their grant date fair values. See Note 10.

Revenue and expense recognition

The Company must meet four basic criteria before revenue can be recognized: persuasive evidence of an arrangement exists; the delivery has occurred or services rendered; the fee is fixed or determinable; and collectability is reasonably assured. All leases are classified as operating leases. Rental income is recognized on a straight-line basis over the terms of the leases. Straight-line rent is recognized for all tenants with contractual fixed increases in rent that are not included on the Company’s credit watch list. Deferred rent receivable represents rental revenue recognized on a straight-line basis in excess of billed rents. Reimbursements from tenants for real estate taxes and other recoverable operating expenses are recognized as rental income in the period the applicable costs are incurred. Property management fees are recognized in the period earned.

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Costs incurred in connection with leasing (primarily tenant improvements and lease commissions) are capitalized and amortized over the lease period.

Gains from sales of real estate facilities

The Company recognizes gains from sales of real estate facilities at the time of sale using the full accrual method, provided that various criteria related to the terms of the transactions and any subsequent involvement by the Company with the properties sold are met. If the criteria are not met, the Company defers the gains and recognizes them when the criteria are met or uses the installment or cost recovery methods as appropriate under the circumstances.

General and administrative expenses

General and administrative expenses include executive and other compensation, office expense, professional fees, acquisition transaction costs, state income taxes and other such administrative items.

Income taxes

The Company has qualified and intends to continue to qualify as a REIT, as defined in Section 856 of the Internal Revenue Code. As a REIT, the Company is not subject to federal income tax to the extent that it distributes its REIT taxable income to its shareholders. A REIT must distribute at least 90% of its taxable income each year. In addition, REITs are subject to a number of organizational and operating requirements. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to federal income tax (including any applicable alternative minimum tax) based on its taxable income using corporate income tax rates. Even if the Company qualifies for taxation as a REIT, the Company may be subject to certain state and local taxes on its income and property and to federal income and excise taxes on its undistributed taxable income. The Company believes it met all organization and operating requirements to maintain its REIT status during 2012, 2011 and 2010 and intends to continue to meet such requirements. Accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements.

The Company can recognize a tax benefit only if it is “more likely than not” that a particular tax position will be sustained upon examination or audit. To the extent that the “more likely than not” standard has been satisfied, the benefit associated with a position is measured as the largest amount that is greater than 50% likely of being recognized upon settlement. As of December 31, 2012, the Company did not recognize any tax benefit for uncertain tax positions.

Accounting for preferred equity issuance costs

The Company records issuance costs as a reduction to paid-in capital on its balance sheet at the time the preferred securities are issued and reflects the carrying value of the preferred equity at the stated value. The Company records issuance costs as non-cash preferred equity distributions at the time it notifies the holders of preferred stock or units of its intent to redeem such shares or units.

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Net income allocation

Net income was allocated as follows for the years ended December 31, (in thousands):

	2012		2011			2010
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units:
Continuing operations	$	5,744	$	14,838		$	10,307
Discontinued operations		226		705			1,287
Total net income allocable to noncontrolling interests — common units		5,970		15,543			11,594
Noncontrolling interests — preferred units:
Distributions to preferred unit holders		174		398			4,521
Issuance costs related to the redemption of preferred units		149		—			582
Gain on repurchase of preferred units, net of issuance costs		—		(7,389	)		—
Total net income allocable to noncontrolling interests — preferred units		323		(6,991	)		5,103
Total net income allocable to noncontrolling interests		6,293		8,552			16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders:
Distributions to preferred shareholders		51,969		41,799			42,730
Issuance costs related to the redemption of preferred stock		17,167		—			3,484
Total net income allocable to preferred shareholders		69,136		41,799			46,214
Restricted stock unit holders:
Continuing operations		135		121			135
Discontinued operations		3		6			17
Total net income allocable to restricted stock unit holders		138		127			152
Common shareholders:
Continuing operations		19,057		49,796			34,635
Discontinued operations		748		2,366			4,324
Total net income allocable to common shareholders		19,805		52,162			38,959
Total net income allocable to PS Business Parks, Inc.		89,079		94,088			85,325
Net income	$	95,372	$	102,640		$	102,022

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Net income per common share

Per share amounts are computed using the number of weighted average common shares outstanding. “Diluted” weighted average common shares outstanding includes the dilutive effect of stock options and restricted stock units under the treasury stock method. “Basic” weighted average common shares outstanding excludes such effect. The Company’s restricted stock units are participating securities and are included in the computation of basic and diluted weighted average common shares outstanding. The Company’s restricted stock unit holders are paid non-forfeitable dividends in excess of the expense recorded which results in a reduction in net income allocable to common shareholders and unit holders. Earnings per share has been calculated as follows for the years ended December 31, (in thousands, except per share amounts):

	2012		2011		2010
Net income allocable to common shareholders	$	19,805	$	52,162	$	38,959
Weighted average common shares outstanding:
Basic weighted average common shares outstanding		24,234		24,516		24,546
Net effect of dilutive stock compensation — based on treasury stock method using average market price		89		83		141
Diluted weighted average common shares outstanding		24,323		24,599		24,687
Net income per common share — Basic	$	0.82	$	2.13	$	1.59
Net income per common share — Diluted	$	0.81	$	2.12	$	1.58

Options to purchase 51,200, 92,000 and 78,000 shares for the years ended December 31 2012, 2011 and 2010, respectively, were not included in the computation of diluted net income per share because such options were considered anti-dilutive.

Segment reporting

The Company views its operations as one segment.

Reclassifications

Certain reclassifications have been made to the consolidated financial statements for 2011 and 2010 in order to conform to the 2012 presentation.

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3. Real estate facilities

The activity in real estate facilities for the years ended December 31, 2012, 2011, and 2010 is as follows (in thousands):

	Land		Buildings  and Equipment			Accumulated Depreciation			Total
Balances at December 31, 2009	$	491,176	$	1,517,596		$	(702,263	)	$	1,306,509
Acquisition of real estate facilities		71,142		223,428			—			294,570
Capital improvements, net		—		40,378			—			40,378
Disposals		—		(9,237	)		9,237			—
Depreciation expense		—		—			(78,868	)		(78,868	)
Transfer to properties held for disposition		—		(160	)		446			286
Balances at December 31, 2010		562,318		1,772,005			(771,448	)		1,562,875
Acquisition of real estate facilities		210,255		344,760			—			555,015
Capital improvements, net		—		49,624			—			49,624
Disposals		—		(10,150	)		10,150			—
Depreciation expense		—		—			(84,682	)		(84,682	)
Transfer to properties held for disposition		—		(467	)		280			(187	)
Balances at December 31, 2011		772,573		2,155,772			(845,700	)		2,082,645
Acquisition of real estate facilities		20,779		30,621			—			51,400
Capital improvements, net		—		61,561			—			61,561
Disposals		—		(12,459	)		12,459			—
Depreciation expense		—		—			(109,494	)		(109,494	)
Transfer to properties held for disposition		—		(47	)		96			49
Balances at December 31, 2012	$	793,352	$	2,235,448		$	(942,639	)	$	2,086,161

The unaudited basis of real estate facilities for federal income tax purposes was approximately $2.0 billion at December 31, 2012. The Company had approximately 23.0% of its properties, in terms of net book value, encumbered by mortgage debt at December 31, 2012.

On December 19, 2012, the Company acquired three multi-tenant flex buildings in Austin, Texas, aggregating 226,000 square feet, for a purchase price of $14.9 million. In connection with this purchase, the Company received a $592,000 credit for committed tenant improvements and lease commissions. On July 24, 2012, the Company acquired a 958,000 square foot industrial park consisting of eight single-story buildings located in Kent Valley, Washington, for a purchase price of $37.6 million. The Company incurred and expensed acquisition transaction costs of $350,000 for the year ended December 31, 2012.

On December 20, 2011, the Company acquired a 5.3 million square foot industrial and flex portfolio located in the Northern California Bay Area (the “Portfolio”), with concentrations in Oakland, Hayward, Fremont, Milpitas, San Jose, Santa Clara and Sunnyvale, for an aggregate purchase price of $520.0 million. In connection with the transaction, the Company assumed a $250.0 million mortgage note described in Note 6. The Company also obtained a $250.0 million unsecured three-year term loan described in Note 5.

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The following table summarizes the assets acquired and liabilities assumed for the Portfolio acquisition during the year ended December 31, 2011 (in thousands):

Land	$	202,131
Buildings and improvements		320,210
Above-market in-place lease value		2,372
Below-market in-place lease value		(4,713	)
Total purchase price		520,000
Mortgage note assumed		(250,000	)
Net operating assets acquired and liabilities assumed		5,171
Total cash paid	$	275,171

The results of operations of the Portfolio acquired have been included in the Company’s consolidated financial statements since the date of acquisition of December 20, 2011. The unaudited pro forma data presented below assumes that the Portfolio acquisition occurred as of the beginning of the respective periods, and includes pro forma adjustments to (i) increase depreciation expense to reflect the Company’s book basis for buildings and improvements acquired, (ii) increase amortization expense to reflect the above-market and below-market in-place lease value acquired, and (iii) increase interest expense to reflect the financing of the Portfolio acquisition related to the $250.0 million mortgage note assumption, borrowings from the term loan and credit facility. Rental income of $42.5 million and $1.2 million related to the Portfolio acquisition for the years ended December 31, 2012 and 2011, respectively, was reported in the Company’s consolidated statements of income. Net losses of $7.2 million and $838,000 related to the Portfolio acquisition for the years end December 31, 2012 and 2011, respectively, were reported in the Company’s consolidated statements of income. The net loss includes rental income less cost of operations, depreciation and mortgage note interest. The Company’s unaudited pro forma results have been prepared for comparative purposes only and do not purport to be indicative of the results of operations that would have occurred had the Portfolio acquisition been consummated at the beginning of the periods presented (in thousands, except per share amounts):

	For The Years  Ended December 31,
	2011		2010
Pro Forma Revenues	$	336,680	$	317,770
Pro Forma Net income	$	95,595	$	91,088
Pro Forma Net income per common share:
Basic	$	1.91	$	1.24
Diluted	$	1.90	$	1.24

On October 13, 2011, the Company acquired an 80,000 square foot multi-tenant office building in Las Colinas, Texas, for $2.8 million. On August 19, 2011, the Company acquired a 46,000 square foot multi-tenant flex building located within its Miami International Commerce Center in Miami, Florida, for $3.5 million. On June 1, 2011, the Company acquired a 140,000 square foot multi-tenant office building, known as the Warren Building, located in Tysons Corner, Virginia, for $27.1 million. In connection with this purchase, the Company received a $298,000 credit for committed tenant improvements and leasing commissions. The Company incurred and expensed acquisition transaction costs of $3.1 million for the year ended December 31, 2011.

On December 15, 2010, the Company acquired Westpark Business Campus, a seven-building multi-tenant office park aggregating 735,000 square feet in Tysons Corner, Virginia, for $140.0 million. In connection with this purchase, the Company received a $1.9 million credit for committed tenant improvements. On July 30, 2010, the Company acquired a two-building multi-tenant office park, known as Tysons Corporate Center, aggregating 270,000 square feet in Tysons Corner, Virginia, for $35.4 million. On June 18, 2010, the Company acquired Parklawn Business Park, a 232,000 square foot multi-tenant office and flex park located in Rockville, Maryland, for $23.4 million. On April 21, 2010, the Company acquired a portfolio of assets in Austin, Texas, aggregating 704,000 square feet of multi-tenant flex parks for $42.9 million. In connection with this purchase, the Company received a $129,000 credit for committed tenant improvements. On March 16, 2010, the Company acquired

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Shady Grove Executive Center, a 350,000 square foot multi-tenant office park located in Rockville, Maryland, for $60.0 million. In connection with this purchase, the Company received a $1.6 million credit for committed tenant improvements and lease commissions. The Company incurred and expensed acquisition transaction costs of $3.3 million for the year ended December 31, 2010.

The following table summarizes the assets acquired and liabilities assumed during the years ended December 31, (in thousands):

	2012			2011			2010
Land	$	20,779		$	210,255		$	71,142
Buildings and improvements		30,621			344,760			223,428
Above-market in-place lease value		709			2,915			6,304
Below-market in-place lease value		(251	)		(4,768	)		(2,348	)
Total purchase price		51,858			553,162			298,526
Mortgage note assumed		—			(250,000	)		—
Net operating assets acquired and liabilities assumed		(836	)		(5,424	)		(2,275	)
Total cash paid	$	51,022		$	297,738		$	296,251

The purchase price of acquired properties is recorded to land, buildings and improvements and intangible assets and liabilities associated with in-place leases (including tenant improvements, unamortized lease commissions, value of above-market and below-market leases, acquired in-place lease values, and tenant relationships, if any) based on their respective estimated fair values. Acquisition related costs are expensed as incurred.

In determining the fair value of the tangible assets of the acquired properties, management considers the value of the properties as if vacant as of the acquisition date. Management must make significant assumptions in determining the value of assets acquired and liabilities assumed. Using different assumptions in the recording of the purchase cost of the acquired properties would affect the timing of recognition of the related revenue and expenses. Amounts recorded to land are derived from comparable sales of land within the same region. Amounts recorded to buildings and improvements, tenant improvements and unamortized lease commissions are based on current market replacement costs and other market information. The amount recorded to acquired in-place leases is determined based on management’s assessment of current market conditions and the estimated lease-up periods for the respective spaces.

In 2010, the Company completed construction on a parcel of land within the Miami International Commerce Center in Miami, Florida, which added 75,000 square feet of rentable small tenant industrial space.

In October, 2012, the Company completed the sale of Quail Valley Business Park, a 66,000 square foot flex park in Houston, Texas, for a gross sales price of $2.3 million, resulting in a net gain of $935,000.

In August, 2011, the Company completed the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million.

In January, 2010, the Company completed the sale of a 131,000 square foot office building located in Houston, Texas, for a gross sales price of $10.0 million, resulting in a net gain of $5.2 million.

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The following table summarizes the condensed results of operations of the properties sold during 2012, 2011 and 2010 (in thousands):

	For the Years Ended December 31,
	2012			2011			2010
Rental income	$	281		$	1,459		$	2,232
Cost of operations		(143	)		(808	)		(1,243	)
Depreciation		(96	)		(291	)		(514	)
Income from discontinued operations	$	42		$	360		$	475

In addition to minimum rental payments, tenants reimburse the Company for their pro rata share of specified operating expenses, which amounted to $617,000 and $852,000 for the years ended December 31, 2011 and 2010, respectively. No such amounts were recorded for the year ended December 31, 2012. These amounts are included as rental income in the table presented above.

4. Leasing activity

The Company leases space in its real estate facilities to tenants primarily under non-cancelable leases generally ranging from one to 10 years. Future minimum rental revenues, excluding recovery of operating expenses under these leases, are as follows as of December 31, 2012 (in thousands):

2013	$	244,595
2014		179,923
2015		124,246
2016		84,954
2017		55,384
Thereafter		92,496
Total	$	781,598

In addition to minimum rental payments, certain tenants reimburse the Company for their pro rata share of specified operating expenses. Such reimbursements amounted to $71.9 million, $59.6 million and $57.2 million, for the years ended December 31, 2012, 2011 and 2010, respectively. These amounts are included as rental income in the accompanying consolidated statements of income.

Leases accounting for 6.1% of total leased square footage are subject to termination options which include leases accounting for 2.7% of total leased square footage having termination options exercisable through December 31, 2013 (unaudited). In general, these leases provide for termination payments should the termination options be exercised. The above table is prepared assuming such options are not exercised.

5. Bank loans

The Company has a line of credit (the “Credit Facility”) with Wells Fargo Bank, National Association (“Wells Fargo”) which expires on August 1, 2015. The Credit Facility has a borrowing limit of $250.0 million. The rate of interest charged on borrowings is equal to a rate ranging from the London Interbank Offered Rate (“LIBOR”) plus 1.00% to LIBOR plus 1.85% depending on the Company’s credit ratings. Currently, the Company’s rate under the Credit Facility is LIBOR plus 1.10%. In addition, the Company is required to pay an annual facility fee ranging from 0.15% to 0.45% of the borrowing limit depending on the Company’s credit ratings (currently 0.15%). The Company had no balance outstanding on the Credit Facility at December 31, 2012. The Company had $185.0 million outstanding on the Credit Facility at an interest rate of 1.41% at December 31, 2011. The Company had $791,000 and $1.1 million of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The Credit Facility requires the Company to meet certain covenants, with which the Company was in compliance at December 31, 2012 and 2011. Interest on outstanding borrowings is payable monthly.

In connection with the Northern California Portfolio acquisition described in Note 3, the Company entered into a term loan on December 20, 2011 with Wells Fargo, as Administrative Agent (the “Term

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Loan”). Pursuant to the Term Loan, the Company borrowed $250.0 million for a three year term through December 31, 2014. The maturity date of the Term Loan Agreement can be extended by one year at the Company’s election. Interest on the amounts borrowed under the Term Loan accrues based on an applicable rate ranging from LIBOR plus 1.15% to LIBOR plus 2.25% depending on the Company’s credit ratings. Currently, the Company’s rate under the Term Loan is LIBOR plus 1.20%. The Company had $200.0 million outstanding on the Term Loan at an interest rate of 1.41% at December 31, 2012 and $250.0 million outstanding at an interest rate of 1.50% at December 31, 2011. The Company had $383,000 and $729,000 of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The covenants and events of default contained in the Credit Facility are incorporated into the Term Loan by reference, and the Term Loan is cross-defaulted to the Credit Facility. The Term Loan can be repaid in full or part at any time prior to its maturity without penalty.

6. Mortgage notes payable

Mortgage notes payable consist of the following (in thousands):

	December 31, 2012		December 31, 2011
5.45% mortgage note, secured by 4.8 million square feet of commercial properties with a net book value of $448.4 million, interest payable monthly, due December, 2016	$	250,000	$	250,000
5.52% mortgage note, secured by one commercial property with a net book value of $14.7 million, principal and interest payable monthly, repaid January, 2013		9,036		9,311
5.68% mortgage note, secured by one commercial property with a net book value of $16.4 million, principal and interest payable monthly, repaid January, 2013		9,066		9,337
5.73% mortgage note, repaid November, 2012		—		13,436
Total	$	268,102	$	282,084

At December 31, 2012, mortgage notes payable had a weighted average interest rate of 5.46% and a weighted average maturity of 3.7 years with principal payments as follows (in thousands):

2013	$	18,102
2014		—
2015		—
2016		250,000
Total	$	268,102

7. Noncontrolling interests

As described in Note 2, the Company reports noncontrolling interests within equity in the consolidated financial statements, but separate from the Company’s shareholders’ equity. In addition, net income allocable to noncontrolling interests is shown as a reduction from net income in calculating net income allocable to common shareholders.

Common partnership units

The Company presents the accounts of PSB and the Operating Partnership on a consolidated basis. Ownership interests in the Operating Partnership that can be redeemed for common stock, other than PSB’s interest, are classified as noncontrolling interests — common units in the consolidated financial statements. Net income allocable to noncontrolling interests — common units consists of the common units’ share of the consolidated operating results after allocation to preferred units and shares. Beginning one year from the date of admission as a limited partner (common units) and subject to certain limitations described below, each limited partner other than PSB has the right to require the redemption of its partnership interest.

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A limited partner (common units) that exercises its redemption right will receive cash from the Operating Partnership in an amount equal to the market value (as defined in the Operating Partnership Agreement) of the partnership interests redeemed. In lieu of the Operating Partnership redeeming the common units for cash, PSB, as general partner, has the right to elect to acquire the partnership interest directly from a limited partner exercising its redemption right, in exchange for cash in the amount specified above or by issuance of one share of PSB common stock for each unit of limited partnership interest redeemed.

A limited partner (common units) cannot exercise its redemption right if delivery of shares of PSB common stock would be prohibited under the applicable articles of incorporation, or if the general partner believes that there is a risk that delivery of shares of common stock would cause the general partner to no longer qualify as a REIT, would cause a violation of the applicable securities laws, or would result in the Operating Partnership no longer being treated as a partnership for federal income tax purposes.

At December 31, 2012, there were 7,305,355 common units owned by PS, which are accounted for as noncontrolling interests. On a fully converted basis, assuming all 7,305,355 noncontrolling interests — common units were converted into shares of common stock of PSB at December 31, 2012, the noncontrolling interests — common units would convert into 23.1% of the shares of common stock then outstanding. Combined with PS’s existing common stock ownership, on a fully converted basis, PS has a combined ownership of 41.5% of the Company’s common equity. At the end of each reporting period, the Company determines the amount of equity (book value of net assets) which is allocable to the noncontrolling interest based upon the ownership interest, and an adjustment is made to the noncontrolling interest, with a corresponding adjustment to paid-in capital, to reflect the noncontrolling interests’ equity interest in the Company.

Preferred partnership units

Through the Operating Partnership, the Company had the following preferred units outstanding as of December 31, 2012 and 2011:

								December 31, 2012				December 31, 2011
Series	Issuance Date		Earliest Potential Redemption  Date		Dividend Rate			Units Outstanding		Amount (in  thousands)		Units Outstanding		Amount (in  thousands)
Series N		December, 2005		December, 2010		7.125	%		—	$	—		223,300	$	5,583
Total									—	$	—		223,300	$	5,583

On June 8, 2012, the Company redeemed 223,300 units of its 7.125% Series N Cumulative Redeemable Preferred Units for $5.6 million. The Company reported the excess of the redemption amount over the carrying amount of $149,000, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

In February, 2011, the Company paid an aggregate of $39.1 million to repurchase 1,710,000 units of its 7.50% Series J Cumulative Redeemable Preferred Units and 203,400 units of its 6.55% Series Q Cumulative Redeemable Preferred Units for a weighted average purchase price of $20.43 per unit. The aggregate par value of the repurchased preferred units was $47.8 million, which generated a gain of $7.4 million, net of original issuance costs of $1.4 million, which was added to net income allocable to common shareholders and unit holders for the year ended December 31, 2011.

On May 12, 2010, the Company redeemed 800,000 units of its 7.950% Series G Cumulative Redeemable Preferred Units for $20.0 million. The Company reported the excess of the redemption amount over the carrying amount of $582,000, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

8. Related party transactions

The Operating Partnership manages industrial, office and retail facilities for PS. These facilities, all located in the United States, operate under the “Public Storage” or “PS Business Parks” names. The PS

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Business Parks name and logo is owned by PS and licensed to the Company under a non-exclusive, royalty-free license agreement. The license can be terminated by either party for any reason with six months written notice.

Under the property management contract with PS, the Operating Partnership is compensated based on a percentage of the gross revenues of the facilities managed. Under the supervision of the property owners, the Operating Partnership coordinates rental policies, rent collections, marketing activities, the purchase of equipment and supplies, maintenance activities, and the selection and engagement of vendors, suppliers and independent contractors. In addition, the Operating Partnership assists and advises the property owners in establishing policies for the hire, discharge and supervision of employees for the operation of these facilities, including property managers and leasing, billing and maintenance personnel.

The property management contract with PS is for a seven-year term with the agreement automatically extending for an additional one-year period upon each one-year anniversary of its commencement (unless cancelled by either party). Either party can give notice of its intent to cancel the agreement upon expiration of its current term. Management fee revenues under this contract were $649,000, $684,000 and $672,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

PS also provides property management services for the self-storage component of two assets owned by the Company. These self-storage facilities, located in Palm Beach County, Florida, operate under the “Public Storage” name.

Under the property management contract, PS is compensated based on a percentage of the gross revenues of the facilities managed. Under the supervision of the Company, PS coordinates rental policies, rent collections, marketing activities, the purchase of equipment and supplies, maintenance activities, and the selection and engagement of vendors, suppliers and independent contractors. In addition, PS is responsible in establishing the policies for the hire, discharge and supervision of employees for the operation of these facilities, including on-site managers, assistant managers and associate managers.

Either the Company or PS can cancel the property management contract upon 60 days’ notice. Management fee expenses under the contract were $55,000, $52,000 and $48,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

Pursuant to a cost sharing and administrative services agreement, the Company shares costs with PS for certain administrative services, which are allocated to PS in accordance with a methodology intended to fairly allocate those costs. These costs totaled $441,000, $442,000 and $543,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

The Company had amounts due from PS of $243,000 and $205,000 at December 31, 2012 and 2011, respectively, for these contracts, as well as for certain operating expenses paid by the Company on behalf of PS.

On February 9, 2011, the Company entered into an agreement with PS to borrow $121.0 million with a maturity date of August 9, 2011 at an interest rate of LIBOR plus 0.85%. The Company repaid, in full, the note payable to PS upon maturity. Interest expense under this note payable was $664,000 for the year ended December 31, 2011.

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9. Shareholders’ equity

Preferred stock

As of December 31, 2012 and 2011, the Company had the following series of preferred stock outstanding:

								December 31, 2012				December 31, 2011
Series	Issuance Date		Earliest Potential Redemption Date		Dividend Rate			Shares Outstanding		Amount (in  thousands)		Shares Outstanding		Amount (in  thousands)
Series R		October, 2010		October, 2015		6.875	%		3,000	$	75,000		3,000	$	75,000
Series S		January, 2012		January, 2017		6.450	%		9,200		230,000		—		—
Series T		May, 2012		May, 2017		6.000	%		14,000		350,000		—		—
Series U		September, 2012		September, 2017		5.750	%		9,200		230,000		—		—
Series H		January & October, 2004		January, 2009		7.000	%		—		—		6,341		158,520
Series I		April, 2004		April, 2009		6.875	%		—		—		2,745		68,626
Series M		May, 2005		May, 2010		7.200	%		—		—		3,182		79,550
Series O		June & August, 2006		June, 2011		7.375	%		—		—		3,384		84,600
Series P		January, 2007		January, 2012		6.700	%		—		—		5,290		132,250
Total									35,400	$	885,000		23,942	$	598,546

On October 9, 2012, the Company completed the redemption of its 6.70% Cumulative Preferred Stock, Series P, at its par value of $132.3 million. The Company reported the excess of the redemption amount over the carrying amount of $3.8 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

On September 14, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 5.75% Cumulative Preferred Stock, Series U, at $25.00 per depositary share.

On June 15, 2012, the Company completed the redemption of its 7.00% Cumulative Preferred Stock, Series H, at its par value of $158.5 million and its 6.875% Cumulative Preferred Stock, Series I, at its par value of $68.6 million. The Company reported the excess of the redemption amount over the carrying amount of $8.1 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year months ended December 31, 2012.

On May 14, 2012, the Company issued $350.0 million or 14.0 million depositary shares, each representing 1/1,000 of a share of the 6.00% Cumulative Preferred Stock, Series T, at $25.00 per depositary share.

During February, 2012, the Company completed the redemption of its 7.20% Cumulative Preferred Stock, Series M, at its par value of $79.6 million and its 7.375% Cumulative Preferred Stock, Series O, at its par value of $84.6 million. The Company reported the excess of the redemption amount over the carrying amount of $5.3 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

On January 18, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 6.45% Cumulative Preferred Stock, Series S, at $25.00 per depositary share.

On October 15, 2010, the Company issued $75.0 million or 3.0 million depositary shares, each representing 1/1,000 of a share of the 6.875% Cumulative Preferred Stock, Series R, at $25.00 per depositary share.

On November 8, 2010, the Company completed the redemption of its 7.60% Cumulative Preferred Stock, Series L, at its par value of $48.4 million. The Company reported the excess of the redemption amount over the carrying amount of $1.6 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

On June 7, 2010, the Company completed the redemption of its 7.950% Cumulative Preferred Stock, Series K, at its par value of $54.1 million. The Company reported the excess of the redemption amount over the carrying amount of $1.9 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

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The Company paid $52.0 million, $41.8 million and $42.7 million in distributions to its preferred shareholders for the years ended December 31, 2012, 2011 and 2010, respectively.

Holders of the Company’s preferred stock will not be entitled to vote on most matters, except under certain conditions. In the event of a cumulative arrearage equal to six quarterly dividends, the holders of the preferred stock will have the right to elect two additional members to serve on the Company’s Board of Directors until all events of default have been cured. At December 31, 2012, there were no dividends in arrears.

Except under certain conditions relating to the Company’s qualification as a REIT, the preferred stock is not redeemable prior to the previously noted redemption dates. On or after the respective redemption dates, the respective series of preferred stock will be redeemable, at the option of the Company, in whole or in part, at $25.00 per depositary share, plus any accrued and unpaid dividends. The Company had $28.1 million and $19.7 million of deferred costs in connection with the issuance of preferred stock as of December 31, 2012 and 2011, respectively, which the Company will report as additional non-cash distributions upon notice of its intent to redeem such shares.

Common stock

The Company’s Board of Directors previously authorized the repurchase, from time to time, of up to 6.5 million shares of the Company’s common stock on the open market or in privately negotiated transactions. During the year ended December 31, 2011, the Company repurchased 591,500 shares of common stock at an aggregate cost of $30.3 million. Since inception of the program, the Company has repurchased an aggregate of 4.9 million shares of common stock at an aggregate cost of $183.9 million or an average cost per share of $37.64. Under existing board authorizations, the Company can repurchase an additional 1.6 million shares. No shares of common stock were repurchased under this program during the years ended December 31, 2012 and 2010.

The Company paid $42.7 million ($1.76 per common share), $43.0 million ($1.76 per common share) and $43.3 million ($1.76 per common share) in distributions to its common shareholders for the years ended December 31, 2012, 2011 and 2010, respectively. The portion of the distributions classified as ordinary income was 100.0% for the years ended December 31, 2012, 2011 and 2010. No portion of the distributions was classified as long-term capital gain income for the years ended December 31, 2012, 2011 and 2010. The percentages in the two preceding sentences are unaudited.

Equity stock

In addition to common and preferred stock, the Company is authorized to issue 100.0 million shares of Equity Stock. The Articles of Incorporation provide that the Equity Stock may be issued from time to time in one or more series and give the Board of Directors broad authority to fix the dividend and distribution rights, conversion and voting rights, redemption provisions and liquidation rights of each series of Equity Stock.

10. Stock compensation

PSB has a 2003 Stock Option and Incentive Plan (the “2003 Plan”) covering 1.5 million shares of PSB’s common stock. Under the 2003 Plan, PSB has granted non-qualified options to certain directors, officers and key employees to purchase shares of PSB’s common stock at a price not less than the fair market value of the common stock at the date of grant. Additionally, under the 2003 Plan, PSB has granted restricted stock units to officers and key employees. Effective February 20, 2012, PSB has a 2012 Equity and Performance-Based Incentive Compensation Plan (the “2012 Plan”) covering 1.0 million shares of PSB’s common stock. Under the 2012 Plan, PSB has granted non-qualified options to certain directors to purchase shares of PSB’s common stock at a price not less than the fair market value of the common stock at the date of grant. Additionally, under the 2012 Plan, PSB has granted restricted shares of common stock to certain directors.

Options under the 2003 Plan and 2012 Plan vest over a five-year period from the date of grant at the rate of one fifth per year and expire 10 years after the date of grant. Generally, restricted stock units granted are subject to a six-year vesting schedule, none in year one and 20% for each of the next five years. Certain restricted stock unit grants are subject to a three-year vesting schedule with 33.3% vesting for each of the three years.

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The weighted average grant date fair value of options granted in the years ended December 31, 2012, 2011 and 2010 were $4.85 per share, $5.38 per share and $6.08 per share, respectively. The Company has calculated the fair value of each option grant on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions used for grants for the years ended December 31, 2012, 2011 and 2010, respectively; a dividend yield of 2.6%, 2.9% and 3.3%; expected volatility of 13.4%, 13.9% and 17.5%; expected life of five years; and risk-free interest rates of 0.9%, 1.7% and 2.4%.

The estimated grant-date fair value of restricted stock units is recognized as compensation expense over the applicable vesting period, net of estimates for future forfeitures. Fair value is determined based upon the closing trading price of our common shares on the grant date. The employer portion of payroll taxes is expensed as incurred. The straight-line attribution method is used with respect to option and restricted stock unit grants that are earned solely based upon the passage of time and continued employment. Performance — based restricted stock unit grants are amortized using the accelerated attribution method, with each vesting amortized separately over the individual vesting period.

The weighted average grant date fair value of restricted stock units granted during the years ended December 31, 2012, 2011 and 2010 were $65.14, $51.63 and $54.44, respectively. The Company calculated the fair value of each restricted stock unit grant using the market value on the date of grant.

At December 31, 2012, there were a combined total of 975,000 options and restricted stock units authorized to grant. Information with respect to outstanding options and nonvested restricted stock units granted under the 2003 Plan and 2012 Plan is as follows:

Options:	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contract Life		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2009		542,752		$	39.43
Granted		291,000		$	52.79
Exercised		(243,936	)	$	31.90
Forfeited		(12,000	)	$	58.19
Outstanding at December 31, 2010		577,816		$	48.95
Granted		14,000		$	60.66
Exercised		(24,600	)	$	42.67
Forfeited		—		$	—
Outstanding at December 31, 2011		567,216		$	49.51
Granted		44,000		$	66.69
Exercised		(143,043	)	$	41.30
Forfeited		(13,600	)	$	61.05
Outstanding at December 31, 2012		454,573		$	53.41		6.07 Years	$	5,436
Exercisable at December 31, 2012		229,173		$	51.70		4.54 Years	$	3,146

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Restricted Stock Units:	Number of Units			Weighted Average  Grant Date Fair Value
Nonvested at December 31, 2009		119,091		$	53.64
Granted		13,900		$	54.44
Vested		(44,857	)	$	53.84
Forfeited		(2,460	)	$	55.90
Nonvested at December 31, 2010		85,674		$	53.60
Granted		8,700		$	51.63
Vested		(29,890	)	$	55.88
Forfeited		(5,260	)	$	52.70
Nonvested at December 31, 2011		59,224		$	52.24
Granted		17,800		$	65.14
Vested		(20,094	)	$	51.36
Forfeited		(3,840	)	$	53.95
Nonvested at December 31, 2012		53,090		$	55.69

Effective January 1, 2012, the Company entered into a performance-based restricted stock unit program, the Senior Management Long-Term Equity Incentive Program for 2012-2015 (“LTEIP”), with selected employees of the Company. Under the LTEIP, the Company established a targeted restricted stock unit award for selected employees, which would be earned only if the Company achieved defined targets during 2012 to 2015. The first type of award is an annual award following the end of each of the four years in the program, with the award subject to and based on the achievement of defined targets during the previous year. The second type of award is an award based on achieving defined targets during the cumulative four-year period 2012-2015. In the event the defined target is not achieved for an annual award, the shares allocated for award for such year are added to the shares that may be received if the four-year target is achieved. Both types of restricted stock unit awards vest in three equal annual installments beginning one year from the date of award. Up to approximately 38,449 restricted stock units would be granted for each of the four years assuming achievement was met and up to approximately 312,220 restricted stock units would be granted for the cumulative four-year period assuming achievement was met. The target for 2012 was not achieved and therefore the shares allocated for 2012 were added to the shares that may be received if the four-year target is achieved. Net compensation expense of $3.9 million related to the LTEIP was recognized during the year ended December 31, 2012.

Included in the Company’s consolidated statements of income for the years ended December 31, 2012, 2011 and 2010 was $419,000, $486,000 and $509,000, respectively, in net compensation expense related to stock options. Net compensation expense of $4.7 million (includes $3.9 million from the LTEIP noted above,) $920,000 and $1.5 million related to restricted stock units was recognized during the years ended December 31, 2012, 2011 and 2010, respectively.

As of December 31, 2012, there was $979,000 of unamortized compensation expense related to stock options expected to be recognized over a weighted average period of 2.6 years. As of December 31, 2012, there was $23.8 million (includes $21.6 million from the LTEIP noted above) of unamortized compensation expense related to restricted stock units expected to be recognized over a weighted average period of 5.8 years.

Cash received from 143,043 stock options exercised during the year ended December 31, 2012 was $5.9 million. Cash received from 24,600 stock options exercised for the year ended December 31, 2011 was $1.1 million. Cash received from 243,936 stock options exercised during the year ended December 31, 2010 was $7.8 million. The aggregate intrinsic value of the stock options exercised during the years ended December 31, 2012, 2011 and 2010 was $3.4 million, $457,000 and $5.3 million, respectively.

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During the year ended December 31, 2012, 20,094 restricted stock units vested; in settlement of these units, 13,248 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2012 was $1.3 million. During the year ended December 31, 2011, 29,890 restricted stock units vested; in settlement of these units, 18,907 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2011 was $1.7 million. During the year ended December 31, 2010, 44,857 restricted stock units vested; in settlement of these units, 27,732 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2010 was $2.4 million.

In May of 2004, the shareholders of the Company approved the issuance of up to 70,000 shares of common stock under the Retirement Plan for Non-Employee Directors (the “Director Plan”). Under the Director Plan, the Company grants 1,000 shares of common stock for each year served as a director up to a maximum of 5,000 shares issued upon retirement. In December of 2011, the Director Plan was amended to increase the maximum shares from 5,000 shares to 7,000 shares, 1,000 shares of common stock for each year served as a director. Beginning in 2012, all grants of common stock to directors were under the 2012 Plan. The Company recognizes compensation expense with regards to grants to be issued in the future under the Director Plan. As a result, included in the Company’s consolidated statements of income was $287,000, $559,000 and $153,000 in compensation expense for the years ended December 31, 2012, 2011 and 2010, respectively. As of December 31, 2012, 2011 and 2010, there was $1.2 million, $514,000 and $339,000, respectively, of unamortized compensation expense related to these shares. In April, 2012, the Company issued 14,000 shares to two directors upon retirement with an aggregate fair value of $956,000. In January, 2011, the Company issued 5,000 shares to a director upon retirement with an aggregate fair value of $290,000. No shares were issued during the years ended December 31, 2010.

11. Supplementary quarterly financial data (unaudited)

	Three Months Ended
	March 31, 2012		June 30, 2012		September 30, 2012		December 31, 2012
	(In thousands, except per share data)
Revenues	$	84,677	$	85,627	$	87,020	$	89,224
Cost of operations	$	28,115	$	27,717	$	29,294	$	28,982
Net income allocable to common shareholders	$	3,467	$	1,410	$	5,172	$	9,760
Net income per share:
Basic	$	0.14	$	0.06	$	0.21	$	0.40
Diluted	$	0.14	$	0.06	$	0.21	$	0.40
	Three Months Ended
	March 31, 2011		June 30, 2011		September 30, 2011		December 31, 2011
	(In thousands, except per share data)
Revenues	$	73,461	$	72,970	$	76,463	$	74,563
Cost of operations	$	25,655	$	24,156	$	24,778	$	25,328
Net income allocable to common shareholders	$	16,562	$	11,374	$	15,444	$	8,801
Net income per share:
Basic	$	0.67	$	0.46	$	0.63	$	0.36
Diluted	$	0.67	$	0.46	$	0.63	$	0.36

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12. Commitments and contingencies

Substantially all of the Company’s properties have been subjected to Phase I environmental reviews. Such reviews have not revealed, nor is management aware of, any probable or reasonably possible environmental costs that management believes would have a material adverse effect on the Company’s business, assets or results of operations, nor is the Company aware of any potentially material environmental liability.

Other than routine litigation and administrative proceedings arising in the ordinary course of business, the Company currently is neither subject to any other material litigation nor, to management’s knowledge, is any material litigation currently threatened against the Company.

13. 401(K) Plan

The Company has a 401(K) savings plan (the “Plan”) in which all eligible employees may participate. The Plan provides for the Company to make matching contributions to all eligible employees up to 4% of their annual salary dependent on the employee’s level of participation. For the years ended December 31, 2012, 2011 and 2010, $345,000, $328,000 and $297,000, respectively, was charged as expense related to this plan.

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PS BUSINESS PARKS, INC.

SCHEDULE III—REAL ESTATE AND ACCUMULATED DEPRECIATION

DECEMBER 31, 2012

(DOLLARS IN THOUSANDS)

				Initial Cost to Company				Cost Capitalized Subsequent to Acquisition		Gross Amount at Which Carried at December 31, 2012
Description	Location	Encumbrances		Land		Buildings and Improvements		Buildings and Improvements		Land		Buildings and Improvements		Total		Accumulated Depreciation		Year(s) Acquired	Depreciable Lives (Years)
Mesa	Mesa, AZ	$	—	$	675	$	1,692	$	2,758	$	675	$	4,450	$	5,125	$	3,390	1997		5-30
Corporate/Metro Park Phoenix	Phoenix, AZ		—		5,130		17,514		2,823		5,130		20,337		25,467		10,467	1999/2003		5-30
Tempe/McKellips	Tempe, AZ		—		195		522		587		195		1,109		1,304		758	1997		5-30
University	Tempe, AZ		—		2,805		7,107		6,124		2,805		13,231		16,036		8,827	1997		5-30
Concord Business Park	Concord, CA		—		12,454		20,491		534		12,454		21,025		33,479		1,343	2011		5-30
Bayview Business Park	Fremont, CA		7,300		4,990		4,831		42		4,990		4,873		9,863		362	2011		5-30
Christy Business Park	Fremont, CA		14,200		11,450		16,254		186		11,450		16,440		27,890		1,138	2011		5-30
Industrial Drive Distribution Center	Fremont, CA		5,300		7,482		6,812		101		7,482		6,913		14,395		522	2011		5-30
Bay Center Business Park	Hayward, CA		27,500		19,052		50,501		333		19,052		50,834		69,886		3,719	2011		5-30
Cabot Distribution Center	Hayward, CA		9,300		5,859		10,811		270		5,859		11,081		16,940		517	2011		5-30
Diablo Business Park	Hayward, CA		—		9,102		15,721		427		9,102		16,148		25,250		1,243	2011		5-30
Eden Landing	Hayward, CA		4,800		3,275		6,174		8		3,275		6,182		9,457		520	2011		5-30
Hayward Business Park	Hayward, CA		46,400		28,256		54,418		795		28,256		55,213		83,469		2,994	2011		5-30
Huntwood Business Park	Hayward, CA		11,600		7,391		11,819		303		7,391		12,122		19,513		727	2011		5-30
Parkway Commerce	Hayward, CA		—		4,398		10,433		4,127		4,398		14,560		18,958		8,091	1997		5-30
Dixon Landing Business Park	Milpitas, CA		30,000		26,301		21,121		552		26,301		21,673		47,974		1,874	2011		5-30
Monterey/Calle	Monterey, CA		—		288		706		303		288		1,009		1,297		597	1997		5-30
Port of Oakland	Oakland, CA		10,800		5,638		11,066		383		5,638		11,449		17,087		802	2011		5-30
Northpointe Business Center	Sacramento, CA		—		3,031		13,826		5,618		3,031		19,444		22,475		11,934	1999		5-30
Sacramento/Northgate	Sacramento, CA		—		1,710		4,567		2,959		1,710		7,526		9,236		4,944	1997		5-30
Charcot Business Park	San Jose, CA		10,300		8,086		11,546		576		8,086		12,122		20,208		984	2011		5-30
Las Plumas	San Jose, CA		—		4,379		12,889		5,660		4,379		18,549		22,928		12,099	1998		5-30
Little Orchard Distribution Center	San Jose, CA		5,900		7,725		3,846		35		7,725		3,881		11,606		277	2011		5-30
Montague Industrial Park	San Jose, CA		14,200		14,476		12,807		149		14,476		12,956		27,432		1,109	2011		5-30
Oakland Road	San Jose, CA		—		3,458		8,765		2,704		3,458		11,469		14,927		6,603	1997		5-30
Rogers Ave	San Jose, CA		—		3,540		4,896		409		3,540		5,305		8,845		1,982	2006		5-30
Doolittle Business Park	San Leandro, CA		4,500		3,929		6,231		180		3,929		6,411		10,340		419	2011		5-30
San Ramon/Norris Canyon	San Ramon, CA		—		1,486		3,642		1,189		1,486		4,831		6,317		2,750	1997		5-30
Commerce Park	Santa Clara, CA		—		17,218		21,914		3,570		17,218		25,484		42,702		13,739	2007		5-30
Santa Clara Tech Park	Santa Clara, CA		—		7,673		15,645		3,551		7,673		19,196		26,869		9,603	2000		5-30
Walsh at Lafayette	Santa Clara, CA		19,300		13,437		17,890		80		13,437		17,970		31,407		2,048	2011		5-30
Airport Blvd.	So. San Francisco, CA		—		899		2,387		638		899		3,025		3,924		1,672	1997		5-30
So. San Francisco/Produce	So. San Francisco, CA		—		776		1,886		411		776		2,297		3,073		1,267	1997		5-30
Kifer Industrial Park	Sunnyvale, CA		28,600		13,227		37,874		15		13,227		37,889		51,116		2,152	2011		5-30
Buena Park Industrial Center	Buena Park, CA		—		3,245		7,703		2,147		3,245		9,850		13,095		5,457	1997		5-30
Carson	Carson, CA		—		990		2,496		1,330		990		3,826		4,816		2,305	1997		5-30
Cerritos Business Center	Cerritos, CA		—		4,218		10,273		3,524		4,218		13,797		18,015		7,844	1997		5-30
Cerritos/Edwards	Cerritos, CA		—		450		1,217		1,193		450		2,410		2,860		1,366	1997		5-30
Culver City	Culver City, CA		—		3,252		8,157		5,776		3,252		13,933		17,185		8,332	1997		5-30
Corporate Pointe	Irvine, CA		—		6,876		18,519		6,174		6,876		24,693		31,569		14,435	2000		5-30
Laguna Hills Commerce Center	Laguna Hills, CA		—		16,261		39,559		4,341		16,261		43,900		60,161		23,359	1997		5-30
Plaza Del Lago	Laguna Hills, CA		—		2,037		5,051		3,548		2,037		8,599		10,636		5,470	1997		5-30

72

				Initial Cost to Company				Cost Capitalized Subsequent to Acquisition		Gross Amount at Which Carried at December 31, 2012
Description	Location	Encumbrances		Land		Buildings and Improvements		Buildings and Improvements		Land		Buildings and Improvements		Total		Accumulated Depreciation		Year(s) Acquired	Depreciable Lives (Years)
Canada	Lake Forest, CA		—		5,508		13,785		4,646		5,508		18,431		23,939		10,410	1997		5-30
Monterey Park	Monterey Park, CA		—		3,078		7,862		1,420		3,078		9,282		12,360		5,218	1997		5-30
Orange County Business Center	Orange County, CA		—		9,405		35,746		17,147		9,405		52,893		62,298		36,846	2003		5-30
Orangewood	Orange County, CA		—		2,637		12,291		3,003		2,637		15,294		17,931		7,560	2003		5-30
Kearney Mesa	San Diego, CA		—		2,894		7,089		2,605		2,894		9,694		12,588		5,542	1997		5-30
Lusk	San Diego, CA		—		5,711		14,049		5,240		5,711		19,289		25,000		11,180	1997		5-30
Rose Canyon Business Park	San Diego, CA		—		15,129		20,054		1,856		15,129		21,910		37,039		9,566	2005		5-30
Signal Hill	Signal Hill, CA		—		6,693		12,699		2,241		6,693		14,940		21,633		6,979	1997/2006		5-30
Studio City/Ventura	Studio City, CA		—		621		1,530		375		621		1,905		2,526		1,113	1997		5-30
Torrance	Torrance, CA		—		2,318		6,069		2,665		2,318		8,734		11,052		5,023	1997		5-30
Boca Commerce	Boca Raton, FL		9,036		7,795		9,258		917		7,795		10,175		17,970		3,295	2006		5-30
MICC	Miami, FL		—		89,529		105,370		35,318		89,529		140,688		230,217		69,205	2003/2011		5-30
Wellington	Wellington, FL		9,066		10,845		18,560		1,307		10,845		19,867		30,712		5,952	2006		5-30
Ammendale	Beltsville, MD		—		4,278		18,380		9,511		4,278		27,891		32,169		17,612	1998		5-30
Gaithersburg/Christopher	Gaithersburg, MD		—		475		1,203		535		475		1,738		2,213		1,063	1997		5-30
Metro Park	Rockville, MD		—		33,995		94,463		33,125		33,995		127,588		161,583		69,333	2001		5-30
Parklawn Business Park	Rockville, MD		—		3,387		19,628		2,500		3,387		22,128		25,515		3,755	2010		5-30
Shady Grove	Rockville, MD		—		5,372		50,727		6,614		5,372		57,341		62,713		8,745	2010		5-30
Westech Business Park	Silver Spring, MD		—		25,261		74,572		10,012		25,261		84,584		109,845		40,437	2006		5-30
Cornell Oaks	Beaverton, OR		—		20,616		63,235		17,667		20,616		80,902		101,518		41,662	2001		5-30
Creekside	Beaverton, OR		—		15,007		47,125		22,022		15,007		69,147		84,154		42,633	1998/2000		5-30
Milwaukie	Milwaukie, OR		—		1,125		2,857		1,613		1,125		4,470		5,595		2,627	1997		5-30
Empire Commerce	Dallas, TX		—		304		1,545		814		304		2,359		2,663		1,545	1998		5-30
Northgate	Dallas, TX		—		1,274		5,505		3,731		1,274		9,236		10,510		5,428	1998		5-30
Westwood Business Park	Farmers Branch, TX		—		941		6,884		1,503		941		8,387		9,328		4,026	2003		5-30
Eastgate	Garland, TX		—		480		1,203		568		480		1,771		2,251		1,045	1997		5-30
NFTZ (1)	Irving, TX		—		1,517		6,499		1,836		1,517		8,335		9,852		5,353	1998		5-30
Royal Tech	Irving, TX		—		13,989		54,113		19,760		13,989		73,873		87,862		40,504	1998-2000/2011		5-30
La Prada	Mesquite, TX		—		495		1,235		629		495		1,864		2,359		1,102	1997		5-30
The Summit	Plano, TX		—		1,536		6,654		3,674		1,536		10,328		11,864		6,657	1998		5-30
Richardson/Business Parkway	Richardson, TX		—		799		3,568		2,363		799		5,931		6,730		3,881	1998		5-30
Ben White	Austin, TX		—		1,550		7,015		1,802		1,550		8,817		10,367		4,611	1998		5-30
Lamar Business Park	Austin, TX		—		2,528		6,596		3,978		2,528		10,574		13,102		7,944	1997		5-30
McKalla	Austin, TX		—		1,945		13,212		1,805		1,945		15,017		16,962		5,043	1998/2012		5-30
Rutland	Austin, TX		—		2,022		9,397		3,618		2,022		13,015		15,037		6,515	1998/1999		5-30
Waterford	Austin, TX		—		2,108		9,649		3,206		2,108		12,855		14,963		7,637	1999		5-30
Braker Business Park	Austin, TX		—		1,874		13,990		919		1,874		14,909		16,783		3,213	2010		5-30
McNeil	Austin, TX		—		2,314		17,044		1,512		2,314		18,556		20,870		4,224	1999/2010/2012		5-30
Mopac Business Park	Austin, TX		—		719		3,579		330		719		3,909		4,628		791	2010		5-30
Southpark Business Park	Austin, TX		—		1,266		9,882		748		1,266		10,630		11,896		2,197	2010		5-30
Bren Mar	Alexandria, VA		—		2,197		5,380		3,670		2,197		9,050		11,247		5,358	1997		5-30
Eisenhower	Alexandria, VA		—		1,440		3,635		2,372		1,440		6,007		7,447		3,920	1997		5-30
Beaumont	Chantilly, VA		—		4,736		11,051		1,480		4,736		12,531		17,267		5,431	2006		5-30
Dulles South/Sullyfield	Chantilly, VA		—		1,373		6,810		2,645		1,373		9,455		10,828		5,342	1999		5-30
Lafayette	Chantilly, VA		—		1,680		13,398		4,218		1,680		17,616		19,296		10,731	1999/2000		5-30
Park East	Chantilly, VA		—		3,851		18,029		9,252		3,851		27,281		31,132		13,682	1999		5-30
Fair Oaks Business Park	Fairfax, VA		—		13,598		36,232		5,181		13,598		41,413		55,011		19,935	2004/2007		5-30
Prosperity Business Campus	Fairfax, VA		—		23,147		67,575		24,636		23,147		92,211		115,358		48,017	2001		5-30
Monroe	Herndon, VA		—		6,737		18,911		9,207		6,737		28,118		34,855		17,080	1997/1999		5-30
Gunston	Lorton, VA		—		4,146		17,872		4,489		4,146		22,361		26,507		12,634	1998		5-30

73

				Initial Cost to Company				Cost Capitalized Subsequent to Acquisition		Gross Amount at Which Carried at December 31, 2012
Description	Location	Encumbrances		Land		Buildings and Improvements		Buildings and Improvements		Land		Buildings and Improvements		Total		Accumulated Depreciation		Year(s) Acquired	Depreciable Lives (Years)
Westpark Business Campus	McLean, VA		—		53,882		111,253		15,612		53,882		126,865		180,747		15,787	2010/2011		5-30
Alban Road	Springfield, VA		—		1,935		4,736		4,618		1,935		9,354		11,289		6,044	1997		5-30
I-95	Springfield, VA		—		3,535		15,672		10,093		3,535		25,765		29,300		17,657	2000		5-30
Northpointe	Sterling, VA		—		2,767		8,778		4,026		2,767		12,804		15,571		8,512	1997/1998		5-30
Shaw Road	Sterling, VA		—		2,969		10,008		3,768		2,969		13,776		16,745		9,254	1998		5-30
Tysons Corporate Center	Vienna, VA		—		9,885		25,302		7,738		9,885		33,040		42,925		4,889	2010		5-30
Woodbridge	Woodbridge, VA		—		1,350		3,398		1,623		1,350		5,021		6,371		3,087	1997		5-30
212th Business Park	Kent, WA		—		19,573		17,695		1,489		19,573		19,184		38,757		461	2012		5-30
Overlake	Redmond, WA		—		27,761		49,353		5,568		27,761		54,921		82,682		26,465	2007		5-30
Renton	Renton, WA		—		330		889		517		330		1,406		1,736		840	1997		5-30
		$	268,102	$	793,352	$	1,801,678	$	433,770	$	793,352	$	2,235,448	$	3,028,800	$	942,639

(1) The Company owns two properties that are subject to ground leases in Las Colinas, Texas, expiring in 2019 and 2020, each with one 10 year extension option.

74

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Dated: February 22, 2013
PS BUSINESS PARKS, INC.
By:	/s/ Joseph D. Russell, Jr.
	Joseph D. Russell, Jr.
	President and Chief Executive Officer

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Signature	Title	Date
/s/ Ronald L. Havner, Jr. Ronald L. Havner, Jr.	Chairman of the Board	February 22, 2013
/s/ Joseph D. Russell, Jr. Joseph D. Russell, Jr.	President, Director and Chief Executive Officer (principal executive officer)	February 22, 2013
/s/ Edward A. Stokx Edward A. Stokx	Chief Financial Officer (principal financial officer and principal accounting officer)	February 22, 2013
/s/ Jennifer Holden Dunbar Jennifer Holden Dunbar	Director	February 22, 2013
/s/ James H. Kropp James H. Kropp	Director	February 22, 2013
/s/ Sara Grootwassink Lewis Sara Grootwassink Lewis	Director	February 22, 2013
/s/ Michael V. McGee Michael V. McGee	Director	February 22, 2013
/s/ Gary E. Pruitt Gary E. Pruitt	Director	February 22, 2013
/s/ Peter Schultz Peter Schultz	Director	February 22, 2013

75

PS BUSINESS PARKS, INC.

EXHIBIT INDEX

(Items 15(a)(3) and 15(b))

3.1	Restated Articles of Incorporation. Filed with Registrant’s Registration Statement on Form S-3 (SEC File No. 333-78627) and incorporated herein by reference.
3.2	Restated Bylaws, as amended. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
3.3	Certificate of Determination of Preferences of 8.75% Series C Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
3.4	Certificate of Determination of Preferences of 8.875% Series X Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
3.5	Amendment to Certificate of Determination of Preferences of 8.875% Series X Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
3.6	Certificate of Determination of Preferences of 8.875% Series Y Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2000 (SEC File No. 001-10709) and incorporated herein by reference.
3.7	Certificate of Determination of Preferences of 9.50% Series D Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated May 7, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
3.8	Amendment to Certificate of Determination of Preferences of 9.50% Series D Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
3.9	Certificate of Determination of Preferences of 9 1/4% Series E Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
3.10	Certificate of Determination of Preferences of 8.75% Series F Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated January 18, 2002 (SEC File No. 001-10709) and incorporated herein by reference.
3.11	Certificate of Determination of Preferences of 7.95% Series G Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
3.12	Certificate of Determination of Preferences of 7.00% Series H Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. filed with Registrant’s Current Report on Form 8-K dated January 16, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
3.13	Certificate of Determination of Preferences of 6.875% Series I Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated March 31, 2004 and incorporated herein by reference.
3.14	Certificate of Determination of Preferences of 7.50% Series J Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
3.15	Certificate of Determination of Preferences of 7.950% Series K Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated June 24, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
3.16	Certificate of Determination of Preferences of 7.60% Series L Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated August 23, 2004 (SEC File No. 001-10709) and incorporated herein by reference.

76

3.17	Certificate of Correction of Certificate of Determination of Preferences for the 7.00% Cumulative Preferred Stock, Series H of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated October 18, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
3.18	Amendment to Certificate of Determination of Preferences for the 7.00% Cumulative Preferred Stock, Series H of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated October 18, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
3.19	Certificate of Determination of Preferences of 7 1/8% Series N Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated December 16, 2005 (SEC File No. 001-10709) and incorporated herein by reference.
3.20	Certificate of Determination of Preferences of 6.70% Series P Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated January 9, 2007 (SEC File No. 001-10709) and incorporated herein by reference.
3.21	Certificate of Determination of Preferences of 6.55% Series Q Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated March 16, 2007 (SEC File No. 001-10709) and incorporated herein by reference.
3.22	Certificate of Determination of Preferences of 6.875% Cumulative Preferred Stock, Series R of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated October 7, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
3.23	Certificate of Determination of Preferences of 6.45% Cumulative Preferred Stock, Series S of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated January 11, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
3.24	Certificate of Determination of Preferences of 6.00% Series T Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Filed with Registrant’s Current Report on Form 8-K dated May 7, 2012 (SEC File No. 001-10709) and incorporated herein by reference
3.25	Certificate of Determination of Preferences of 5.75% Series U Cumulative Redeemable Preferred Stock of PS Business Parks, Inc. Field with Registrant’s Current Report on Form 8-K dated September 7, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
4.1	Deposit Agreement Relating to 7.00% Cumulative Preferred Stock, Series H of PS Business Parks, Inc., dated as of January 15, 2004. Filed with Registrant’s Current Report on Form 8-K dated January 15, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
4.2	Deposit Agreement Relating to 6.875% Cumulative Preferred Stock, Series I of PS Business Parks, Inc., dated as of March 31, 2004. Filed with Registrant’s Current Report on Form 8-K dated March 31, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
4.3	Deposit Agreement Relating to 6.70% Cumulative Preferred Stock, Series P of PS Business Parks, Inc., dated as of January 9, 2007. Filed with Registrant’s Current Report on Form 8-K dated January 9, 2007 (SEC File No. 001-10709) and incorporated herein by reference.
4.4	Deposit Agreement Relating to 6.875% Cumulative Preferred Stock, Series R of PS Business Parks, Inc., dated as of October 7, 2010. Filed with Registrant’s Current Report on Form 8-K dated October 7, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
4.5	Deposit Agreement Relating to 6.45% Cumulative Preferred Stock, Series S of PS Business Parks, Inc., dated as of January 10, 2012. Filed with Registrant’s Current Report on Form 8-K dated January 11, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
4.6	Deposit Agreement Relating to 6.00% Cumulative Preferred Stock, Series T of PS Business Parks, Inc. dated as of May 3, 2012. Filed with Registrant’s Current Report on Form 8-K dated May 7, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
4.7	Deposit Agreement Relating to 5.75% Cumulative Preferred Stock, Series U of PS Business Parks, Inc. dated as of September 5, 2012. Filed with Registrant’s Current Report on Form 8-K dated September 7, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.1	Amended Management Agreement between Storage Equities, Inc. and Public Storage Commercial Properties Group, Inc. dated as of February 21, 1995. Filed with PS’s Annual Report on Form 10-K for the year ended December 31, 1994 (SEC File No. 001-08389) and incorporated herein by reference.

77

10.2	Agreement of Limited Partnership of PS Business Parks, L.P. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 1998 (SEC File No. 001-10709) and incorporated herein by reference.
10.3*	Offer Letter/ Employment Agreement between Registrant and Joseph D. Russell, Jr., dated as of September 6, 2002. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
10.4*	Form of Indemnity Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1998 (SEC File No. 001-10709) and incorporated herein by reference.
10.5*	Form of Indemnification Agreement for Executive Officers. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.6	Cost Sharing and Administrative Services Agreement dated as of November 16, 1995 by and among PSCC, Inc. and the owners listed therein. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1998 (SEC File No. 001-10709) and incorporated herein by reference.
10.7	Amendment to Cost Sharing and Administrative Services Agreement dated as of January 2, 1997 by and among PSCC, Inc. and the owners listed therein. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1998 (SEC File No. 001-10709) and incorporated herein by reference.
10.8	Accounts Payable and Payroll Disbursement Services Agreement dated as of January 2, 1997 by and between PSCC, Inc. and AOPP LP. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1998 (SEC File No. 001-10709) and incorporated herein by reference.
10.9	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 8.875% Series B Cumulative Redeemable Preferred Units, dated as of April 23, 1999. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
10.10	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 9.25% Series A Cumulative Redeemable Preferred Units, dated as of April 30, 1999. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
10.11	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 8.75% Series C Cumulative Redeemable Preferred Units, dated as of September 3, 1999. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
10.12	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 8.875% Series X Cumulative Redeemable Preferred Units, dated as of September 7, 1999. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
10.13	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to Additional 8.875% Series X Cumulative Redeemable Preferred Units, dated as of September 23, 1999. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 (SEC File No. 001-10709) and incorporated herein by reference.
10.14	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 8.875% Series Y Cumulative Redeemable Preferred Units, dated as of July 12, 2000. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2000 (SEC File No. 001-10709) and incorporated herein by reference.
10.15	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 9.50% Series D Cumulative Redeemable Preferred Units, dated as of May 10, 2001. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
10.16	Amendment No. 1 to Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 9.50% Series D Cumulative Redeemable Preferred Units, dated as of June 18, 2001. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2001 (SEC File No. 001-10709) and incorporated herein by reference.

78

10.17	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 9 1/4% Series E Cumulative Redeemable Preferred Units, dated as of September 21, 2001. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
10.18	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 8.75% Series F Cumulative Redeemable Preferred Units, dated as of January 18, 2002. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2001 (SEC File No. 001-10709) and incorporated herein by reference.
10.19	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.95% Series G Cumulative Redeemable Preferred Units, dated as of October 30, 2002. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
10.20	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.00% Series H Cumulative Redeemable Preferred Units, dated as of January 16, 2004. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
10.21	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.875% Series I Cumulative Redeemable Preferred Units, dated as of April 21, 2004. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.22	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.50% Series J Cumulative Redeemable Preferred Units, dated as of May 27, 2004. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.23	Amendment No. 1 to Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.50% Series J Cumulative Redeemable Preferred Units, dated as of June 17, 2004. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.24	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.95% Series K Cumulative Redeemable Preferred Units, dated as of June 30, 2004. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.25	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.60% Series L Cumulative Redeemable Preferred Units, dated as of August 31, 2004. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.26	Amendment No. 1 to Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7.00% Series H Cumulative Redeemable Preferred Units, dated as of October 25, 2004. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.27	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 7 1/8% Series N Cumulative Redeemable Preferred Units, dated as of December 12, 2005. Filed with Registrant’s Current Report on Form 8-K dated December 16, 2005 (SEC File No. 001-10709) and incorporated herein by reference.
10.28	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.70% Series P Cumulative Redeemable Preferred Units, dated as of January 9, 2007. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2006 (SEC File No. 001-10709) and incorporated herein by reference.
10.29	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.55% Series Q Cumulative Redeemable Preferred Units, dated as of March 12, 2007. Filed with Registrant’s Current Report on Form 8-K dated March 16, 2007 (SEC File No. 001-10709) and incorporated herein by reference.

79

10.30	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.875% Series R Cumulative Redeemable Preferred Units, dated as of October 15, 2010. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
10.31	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.45% Series S Cumulative Redeemable Preferred Units, dated as of January 10, 2012. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.32	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 6.00% Series T Cumulative Preferred Units, Series T, dated as of May 14, 2012. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.33	Amendment to Agreement of Limited Partnership of PS Business Parks, L.P. relating to 5.75% Series U Cumulative Preferred Units, dated as of September 14, 2012. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.34	Registration Rights Agreement by and between PS Business Parks, Inc. and GSEP 2005 Realty Corp., dated as of December 12, 2005, relating to 7.125% Series N Cumulative Redeemable Preferred Units. Filed with Registrant’s Current Report on Form 8-K dated December 16, 2005 (SEC File No. 001-10709) and incorporated herein by reference.
10.35	Amended and Restated Revolving Credit Agreement dated as of October 29, 2002 among PS Business Parks, L.P., Wells Fargo Bank, National Association, as Agent, and the Lenders named therein. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2002 (SEC File No. 001-10709) and incorporated herein by reference.
10.36	Modification Agreement, dated as of December 29, 2003. Filed with the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 and incorporated herein by reference. This exhibit modifies the Amended and Restated Revolving Credit Agreement dated as of October 29, 2002 and filed with the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2002 (SEC File No. 001-10709) and incorporated herein by reference.
10.37	Modification Agreement, dated as of January 23, 2004. Filed with the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 and incorporated herein by reference. This exhibit modifies the Modification Agreement dated as of December 29, 2003 and filed with the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
10.38	Third Modification Agreement, dated as of August 5, 2005. Filed with the Registrant’s Current Report on Form 8-K dated August 5, 2005 (SEC File No. 001-10709) and incorporated herein by reference. This exhibit modifies the Modification Agreement dated as of January 23, 2004 and filed with the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2003 (SEC File No. 001-10709) and incorporated herein by reference.
10.39	Fourth Modification Agreement dated as of July 30, 2008 to Amended and Restated Revolving Credit Agreement dated October 29, 2002. Filed with Registrant’s Current Report on Form 8-K dated August 5, 2008 (SEC File No. 001-10709) and incorporated herein by reference.
10.40	Fifth Modification Agreement dated as of July 28, 2010 to Amended and Restated Revolving Credit Agreement dated October 29, 2002. Filed with Registrant’s Current Report on Form 8-K dated August 2, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
10.41	Promissory Note dated February 9, 2011. Filed with the Registrant’s Current Report on Form 8-K dated February 14, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.42	Sixth Modification Agreement dated as of August 3, 2011 to Amended and Restated Revolving Credit Agreement dated October 29, 2002. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2011 (SEC File No. 001-10709) and incorporated herein by reference.

80

10.43	Loan Agreement, dated November 17, 2006, between Northern California Industrial Portfolio, Inc., a Maryland corporation, and LaSalle Bank National Association, a national banking association. Filed with the Registrant’s Current Report on Form 8-K dated December 20, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.44	Credit Agreement dated as of December 20, 2011, by and among PS Business Parks, L.P., a California limited partnership, as borrower, and Wells Fargo Bank, National Association, as Administrative Agent for the Lenders. Filed with the Registrant’s Current Report on Form 8-K dated December 20, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.45	Seventh Modification Agreement dated as of December 20, 2011 to Amended and Restated Revolving Credit Agreement dated October 29, 2002. Filed with the Registrant’s Current Report on Form 8-K dated December 20, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.46	First Modification Agreement dated December 29, 2011 to Credit Agreement dated December 20, 2011 by and among PS Business Parks, L.P., a California limited partnership, as borrower, and Wells Fargo Bank, National Association, as Administrative Agent for the Lenders. Filed with the Registrant’s Current Report on Form 8-K dated January 5, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.47*	Registrant’s 1997 Stock Option and Incentive Plan. Filed with Registrant’s Registration Statement on Form S-8 (SEC File No. 333-48313) and incorporated herein by reference.
10.48*	Registrant’s 2003 Stock Option and Incentive Plan. Filed with Registrant’s Registration Statement on Form S-8 (SEC File No. 333-104604) and incorporated herein by reference.
10.49*	Amended and Restated Retirement Plan for Non-Employee Directors. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2011 (SEC File No. 001-10709) and incorporated herein by reference.
10.50*	Form of PS Business Parks, Inc. Restricted Stock Unit Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.51*	Form of PS Business Parks, Inc. 2003 Stock Option and Incentive Plan Non-Qualified Stock Option Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.52*	Form of PS Business Parks, Inc. 2003 Stock Option and Incentive Plan Stock Option Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2004 (SEC File No. 001-10709) and incorporated herein by reference.
10.53*	Amendment to Form of Director Stock Option Agreement. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
10.54*	Revised Form of Director Stock Option Agreement. Filed with Registrant’s Annual Report on Form 10-K for the year ended December 31, 2010 (SEC File No. 001-10709) and incorporated herein by reference.
10.55*	Registrant’s 2012 Equity and Performance-Based Incentive Compensation Plan (2012 Plan). Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.56*	Form of Registrant’s 2012 Plan Non-Qualified Stock Option Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
10.57*	Form of Registrant’s 2012 Plan Restricted Stock Unit Agreement. Filed with Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2012 (SEC File No. 001-10709) and incorporated herein by reference.
12	Statement re: Computation of Ratio of Earnings to Fixed Charges. Filed herewith.
21	List of Subsidiaries. Filed herewith.
23	Consent of Independent Registered Public Accounting Firm. Filed herewith.

81

31.1	Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Filed herewith.
31.2	Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Filed herewith.
32.1	Certification of Chief Executive Officer and Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. Filed herewith.
101 .INS	XBRL Instance Document. Filed herewith.
101 .SCH	XBRL Taxonomy Extension Schema. Filed herewith.
101 .CAL	XBRL Taxonomy Extension Calculation Linkbase. Filed herewith.
101 .DEF	XBRL Taxonomy Extension Definition Linkbase. Filed herewith.
101 .LAB	XBRL Taxonomy Extension Label Linkbase. Filed herewith.
101 .PRE	XBRL Taxonomy Extension Presentation Link. Filed herewith.

* Management contract or compensatory plan or arrangement

82

EX-12

Exhibit 12

PS BUSINESS PARKS, INC.

STATEMENT RE: COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(in thousands, except ratio data)

	2012		2011			2010		2009			2008
Income from continuing operations	$	94,395	$	99,563		$	96,394	$	91,368		$	84,106
Interest expense		20,618		5,455			3,534		3,552			3,952
Earnings from continuing operations available to cover fixed charges	$	115,013	$	105,018		$	99,928	$	94,920		$	88,058
Fixed charges (1)	$	20,618	$	5,455		$	3,534	$	3,552		$	3,952
Preferred stock dividends		69,136		41,799			46,214		17,440			46,630
Preferred partnership distributions		323		(6,991	)		5,103		(2,569	)		7,007
Combined fixed charges and preferred distributions	$	90,077	$	40,263		$	54,851	$	18,423		$	57,589
Ratio of earnings from continuing operations to fixed charges		5.6		19.3			28.3		26.7			22.3
Ratio of earnings from continuing operations to combined fixed charges and preferred distributions		1.3		2.6			1.8		5.2			1.5

Supplemental disclosure of Ratio of Funds from Operations (“FFO”) to fixed charges:

	2012		2011			2010		2009			2008
FFO	$	134,472	$	149,797		$	124,420	$	163,074		$	131,558
Interest expense		20,618		5,455			3,534		3,552			3,952
Net income allocable to noncontrolling interests — preferred units		323		(6,991	)		5,103		(2,569	)		7,007
Preferred stock dividends		69,136		41,799			46,214		17,440			46,630
FFO available to cover fixed charges	$	224,549	$	190,060		$	179,271	$	181,497		$	189,147
Fixed charges (1)	$	20,618	$	5,455		$	3,534	$	3,552		$	3,952
Preferred stock dividends (2)		51,969		41,799			42,730		44,662			50,858
Preferred partnership distributions (2)		174		398			4,521		5,848			7,007
Combined fixed charges and preferred distributions paid	$	72,761	$	47,652		$	50,785	$	54,062		$	61,817
Ratio of adjusted FFO to fixed charges		10.9		34.8			50.7		51.1			47.9
Ratio of adjusted FFO to combined fixed charges and preferred distributions paid		3.1		4.0			3.5		3.4			3.1

(1) Fixed charges include interest expense.

(2) Excludes the charge for the issuance costs related to the redemption/repurchase of preferred equity and the gain on the repurchase of preferred equity.

EX-21

Exhibit 21

List of Subsidiaries

The following sets forth the subsidiaries of the Registrant and their respective states of incorporation or organization:

Name	State
American Office Park Properties, TPGP, Inc.	California
PSBP QRS, Inc.	California
Hernmore, Inc.	Maryland
AOPP Acquisition Corp. Two	California
Tenant Advantage, Inc.	California
PS Business Parks, L.P.	California
PSBP Northpointe D, L.L.C.	Virginia
Monroe Parkway, L.L.C.	Virginia
Metro Park I, L.L.C.	Delaware
Metro Park II, L.L.C.	Delaware
Metro Park III, L.L.C.	Delaware
Metro Park IV, L.L.C.	Delaware
Metro Park V, L.L.C.	Delaware
PS Metro Park, L.L.C.	Maryland
PSB Northern California Industrial Portfolio, L.L.C	Delaware
PSBP Springing Member, L.L.C	Delaware
PSBP Westwood GP, L.L.C.	Delaware
PSBP Industrial, L.L.C.	Delaware
Miami International Commerce Center Association, Inc.	Florida
REVX-098, L.L.C.	Delaware
GB, L.L.C.	Maryland
PSBP Meadows L.L.C.	Delaware
PSBP Meadows Member L.L.C.	Delaware
PSB Boca Commerce Park, L.L.C.	Delaware
PSB Wellington Commerce Park I, L.L.C.	Delaware
PSB Wellington Commerce Park II, L.L.C.	Delaware
PSB Wellington Commerce Park III, L.L.C.	Delaware

EX-23

Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the following Registration Statements:

(1) Registration Statement (Form S-8 No. 333-48313) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. 1997 Stock Option and Incentive Plan,

(2) Registration Statement (Form S-8 No. 333-50274) of PS Business Parks, Inc. pertaining to the PS 401(k)/Profit Sharing Plan,

(3) Registration Statement (Form S-8 No. 333-104604) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. 2003 Stock Option and Incentive Plan,

(4) Registration Statement (Form S-8 No. 333-129463) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. Retirement Plan for Non-Employee Directors, and

(5) Registration Statement (Form S-3 No. 333-160104)

of our reports dated February 22, 2013 with respect to the consolidated financial statements and related financial statement schedule of PS Business Parks, Inc., and the effectiveness of internal control over financial reporting of PS Business Parks, Inc., included in this Annual Report on Form 10-K of PS Business Parks, Inc. for the year ended December 31, 2012.

/s/ Ernst & Young, LLP

Los Angeles, California

February 22, 2013

EX-31.1

Exhibit 31.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Joseph D. Russell, Jr. certify that:

1. I have reviewed this annual report on Form 10-K of PS Business Parks, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

/s/    Joseph D. Russell, Jr.        

Name:     Joseph D. Russell, Jr.

Title:       Chief Executive Officer

Date: February 22, 2013

EX-31.2

Exhibit 31.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Edward A. Stokx certify that:

1. I have reviewed this annual report on Form 10-K of PS Business Parks, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

/s/    Edward A. Stokx        

Name:     Edward A. Stokx

Title:       Chief Financial Officer

Date: February 22, 2013

EX-32.1

Exhibit 32.1

Certification of CEO and CFO Pursuant to

18 U.S.C. Section 1350,

as Adopted Pursuant to

Section 906 of the Sarbanes-Oxley Act of 2002

In connection with the Annual Report on Form 10-K of PS Business Parks, Inc. (the “Company”) for the period ending December 31, 2012 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Joseph D. Russell Jr., as Chief Executive Officer of the Company, and Edward A. Stokx, as Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to his knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/    Joseph D. Russell, Jr.        

Name:     Joseph D. Russell, Jr.

Title:       Chief Executive Officer

Date: February 22, 2013

/s/    Edward A. Stokx        

Name:     Edward A. Stokx

Title:       Chief Financial Officer

Date: February 22, 2013

XML

Leasing Activity (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Tenant reimbursements	$ 71.9	$ 59.6	$ 57.2
Percentage of leased asset subjected to termination options	6.10%
Percentage of leased asset exercisable in period	2.70%
Maximum [Member]
Non-cancelable leases term (in years)	10 years
Minimum [Member]
Non-cancelable leases term (in years)	1 year

XML

401(K) Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation and Retirement Disclosure [Abstract]
Matching contributions by employer, percentage	4.00%
Expenses related to 401(k) savings plan	$ 345,000	$ 328,000	$ 297,000

XML

Shareholders' Equity (Common And Equity Stock) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Class of Stock [Line Items]
Shares authorized for repurchase	6,500,000
Aggregate number of common stock repurchased in the period	0		0
Aggregate cost of shares repurchased		$ 30,252
Shares available for repurchase under existing repurchase program	1,600,000
Distributions paid to common shareholders	42,684	43,046	43,254
Common stock distributions per share	$ 1.76	$ 1.76	$ 1.76
Percentage of distributions classified as ordinary income	100.00%	100.00%	100.00%
Equity stock, shares authorized	100,000,000
Since Inception [Member]
Class of Stock [Line Items]
Aggregate number of common stock repurchased in the period	4,900,000	591,500
Aggregate cost of shares repurchased	$ 183,900
Average cost per share of common stock	$ 37.64

XML

Real Estate And Accumulated Depreciation (Real Estate And Accumulated Depreciation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 268,102
Initial Cost to Company, Land	793,352
Initial Cost to Company, Buildings and Improvements	1,801,678
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	433,770
Gross Amount at Which Carried at December 31, 2012, Land	793,352
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	2,235,448
Gross Amount at Which Carried at December 31, 2012, Total	3,028,800
Accumulated Depreciation	942,639
Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Mesa
Location	Mesa, AZ
Initial Cost to Company, Land	675
Initial Cost to Company, Buildings and Improvements	1,692
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,758
Gross Amount at Which Carried at December 31, 2012, Land	675
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	4,450
Gross Amount at Which Carried at December 31, 2012, Total	5,125
Accumulated Depreciation	3,390
Year(s) Acquired	1997
Corporate/Metro Park Phoenix [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Corporate/Metro Park Phoenix
Location	Phoenix, AZ
Initial Cost to Company, Land	5,130
Initial Cost to Company, Buildings and Improvements	17,514
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,823
Gross Amount at Which Carried at December 31, 2012, Land	5,130
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	20,337
Gross Amount at Which Carried at December 31, 2012, Total	25,467
Accumulated Depreciation	10,467
Year(s) Acquired	1999/2003
Tempe/McKellips [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Tempe/McKellips
Location	Tempe, AZ
Initial Cost to Company, Land	195
Initial Cost to Company, Buildings and Improvements	522
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	587
Gross Amount at Which Carried at December 31, 2012, Land	195
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,109
Gross Amount at Which Carried at December 31, 2012, Total	1,304
Accumulated Depreciation	758
Year(s) Acquired	1997
University [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	University
Location	Tempe, AZ
Initial Cost to Company, Land	2,805
Initial Cost to Company, Buildings and Improvements	7,107
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	6,124
Gross Amount at Which Carried at December 31, 2012, Land	2,805
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	13,231
Gross Amount at Which Carried at December 31, 2012, Total	16,036
Accumulated Depreciation	8,827
Year(s) Acquired	1997
Concord Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Concord Business Park
Location	Concord, CA
Initial Cost to Company, Land	12,454
Initial Cost to Company, Buildings and Improvements	20,491
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	534
Gross Amount at Which Carried at December 31, 2012, Land	12,454
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	21,025
Gross Amount at Which Carried at December 31, 2012, Total	33,479
Accumulated Depreciation	1,343
Year(s) Acquired	2011
Bayview Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Bayview Business Park
Location	Fremont, CA
Encumbrances	7,300
Initial Cost to Company, Land	4,990
Initial Cost to Company, Buildings and Improvements	4,831
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	42
Gross Amount at Which Carried at December 31, 2012, Land	4,990
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	4,873
Gross Amount at Which Carried at December 31, 2012, Total	9,863
Accumulated Depreciation	362
Year(s) Acquired	2011
Christy Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Christy Business Park
Location	Fremont, CA
Encumbrances	14,200
Initial Cost to Company, Land	11,450
Initial Cost to Company, Buildings and Improvements	16,254
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	186
Gross Amount at Which Carried at December 31, 2012, Land	11,450
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	16,440
Gross Amount at Which Carried at December 31, 2012, Total	27,890
Accumulated Depreciation	1,138
Year(s) Acquired	2011
Industrial Drive Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Industrial Drive Distribution Center
Location	Fremont, CA
Encumbrances	5,300
Initial Cost to Company, Land	7,482
Initial Cost to Company, Buildings and Improvements	6,812
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	101
Gross Amount at Which Carried at December 31, 2012, Land	7,482
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	6,913
Gross Amount at Which Carried at December 31, 2012, Total	14,395
Accumulated Depreciation	522
Year(s) Acquired	2011
Bay Center Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Bay Center Business Park
Location	Hayward, CA
Encumbrances	27,500
Initial Cost to Company, Land	19,052
Initial Cost to Company, Buildings and Improvements	50,501
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	333
Gross Amount at Which Carried at December 31, 2012, Land	19,052
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	50,834
Gross Amount at Which Carried at December 31, 2012, Total	69,886
Accumulated Depreciation	3,719
Year(s) Acquired	2011
Cabot Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Cabot Distribution Center
Location	Hayward, CA
Encumbrances	9,300
Initial Cost to Company, Land	5,859
Initial Cost to Company, Buildings and Improvements	10,811
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	270
Gross Amount at Which Carried at December 31, 2012, Land	5,859
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	11,081
Gross Amount at Which Carried at December 31, 2012, Total	16,940
Accumulated Depreciation	517
Year(s) Acquired	2011
Diablo Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Diablo Business Park
Location	Hayward, CA
Initial Cost to Company, Land	9,102
Initial Cost to Company, Buildings and Improvements	15,721
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	427
Gross Amount at Which Carried at December 31, 2012, Land	9,102
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	16,148
Gross Amount at Which Carried at December 31, 2012, Total	25,250
Accumulated Depreciation	1,243
Year(s) Acquired	2011
Eden Landing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Eden Landing
Location	Hayward, CA
Encumbrances	4,800
Initial Cost to Company, Land	3,275
Initial Cost to Company, Buildings and Improvements	6,174
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	8
Gross Amount at Which Carried at December 31, 2012, Land	3,275
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	6,182
Gross Amount at Which Carried at December 31, 2012, Total	9,457
Accumulated Depreciation	520
Year(s) Acquired	2011
Hayward Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Hayward Business Park
Location	Hayward, CA
Encumbrances	46,400
Initial Cost to Company, Land	28,256
Initial Cost to Company, Buildings and Improvements	54,418
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	795
Gross Amount at Which Carried at December 31, 2012, Land	28,256
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	55,213
Gross Amount at Which Carried at December 31, 2012, Total	83,469
Accumulated Depreciation	2,994
Year(s) Acquired	2011
Huntwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Huntwood Business Park
Location	Hayward, CA
Encumbrances	11,600
Initial Cost to Company, Land	7,391
Initial Cost to Company, Buildings and Improvements	11,819
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	303
Gross Amount at Which Carried at December 31, 2012, Land	7,391
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,122
Gross Amount at Which Carried at December 31, 2012, Total	19,513
Accumulated Depreciation	727
Year(s) Acquired	2011
Parkway Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Parkway Commerce
Location	Hayward, CA
Initial Cost to Company, Land	4,398
Initial Cost to Company, Buildings and Improvements	10,433
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,127
Gross Amount at Which Carried at December 31, 2012, Land	4,398
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	14,560
Gross Amount at Which Carried at December 31, 2012, Total	18,958
Accumulated Depreciation	8,091
Year(s) Acquired	1997
Dixon Landing Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Dixon Landing Business Park
Location	Milpitas, CA
Encumbrances	30,000
Initial Cost to Company, Land	26,301
Initial Cost to Company, Buildings and Improvements	21,121
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	552
Gross Amount at Which Carried at December 31, 2012, Land	26,301
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	21,673
Gross Amount at Which Carried at December 31, 2012, Total	47,974
Accumulated Depreciation	1,874
Year(s) Acquired	2011
Monterey/Calle [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Monterey/Calle
Location	Monterey, CA
Initial Cost to Company, Land	288
Initial Cost to Company, Buildings and Improvements	706
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	303
Gross Amount at Which Carried at December 31, 2012, Land	288
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,009
Gross Amount at Which Carried at December 31, 2012, Total	1,297
Accumulated Depreciation	597
Year(s) Acquired	1997
Port Of Oakland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Port of Oakland
Location	Oakland, CA
Encumbrances	10,800
Initial Cost to Company, Land	5,638
Initial Cost to Company, Buildings and Improvements	11,066
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	383
Gross Amount at Which Carried at December 31, 2012, Land	5,638
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	11,449
Gross Amount at Which Carried at December 31, 2012, Total	17,087
Accumulated Depreciation	802
Year(s) Acquired	2011
Northpointe Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Northpointe Business Center
Location	Sacramento, CA
Initial Cost to Company, Land	3,031
Initial Cost to Company, Buildings and Improvements	13,826
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,618
Gross Amount at Which Carried at December 31, 2012, Land	3,031
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	19,444
Gross Amount at Which Carried at December 31, 2012, Total	22,475
Accumulated Depreciation	11,934
Year(s) Acquired	1999
Sacramento/Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Sacramento/Northgate
Location	Sacramento, CA
Initial Cost to Company, Land	1,710
Initial Cost to Company, Buildings and Improvements	4,567
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,959
Gross Amount at Which Carried at December 31, 2012, Land	1,710
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	7,526
Gross Amount at Which Carried at December 31, 2012, Total	9,236
Accumulated Depreciation	4,944
Year(s) Acquired	1997
Charcot Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Charcot Business Park
Location	San Jose, CA
Encumbrances	10,300
Initial Cost to Company, Land	8,086
Initial Cost to Company, Buildings and Improvements	11,546
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	576
Gross Amount at Which Carried at December 31, 2012, Land	8,086
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,122
Gross Amount at Which Carried at December 31, 2012, Total	20,208
Accumulated Depreciation	984
Year(s) Acquired	2011
Las Plumas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Las Plumas
Location	San Jose, CA
Initial Cost to Company, Land	4,379
Initial Cost to Company, Buildings and Improvements	12,889
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,660
Gross Amount at Which Carried at December 31, 2012, Land	4,379
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	18,549
Gross Amount at Which Carried at December 31, 2012, Total	22,928
Accumulated Depreciation	12,099
Year(s) Acquired	1998
Little Orchard Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Little Orchard Distribution Center
Location	San Jose, CA
Encumbrances	5,900
Initial Cost to Company, Land	7,725
Initial Cost to Company, Buildings and Improvements	3,846
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	35
Gross Amount at Which Carried at December 31, 2012, Land	7,725
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	3,881
Gross Amount at Which Carried at December 31, 2012, Total	11,606
Accumulated Depreciation	277
Year(s) Acquired	2011
Montague Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Montague Industrial Park
Location	San Jose, CA
Encumbrances	14,200
Initial Cost to Company, Land	14,476
Initial Cost to Company, Buildings and Improvements	12,807
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	149
Gross Amount at Which Carried at December 31, 2012, Land	14,476
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,956
Gross Amount at Which Carried at December 31, 2012, Total	27,432
Accumulated Depreciation	1,109
Year(s) Acquired	2011
Oakland Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Oakland Road
Location	San Jose, CA
Initial Cost to Company, Land	3,458
Initial Cost to Company, Buildings and Improvements	8,765
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,704
Gross Amount at Which Carried at December 31, 2012, Land	3,458
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	11,469
Gross Amount at Which Carried at December 31, 2012, Total	14,927
Accumulated Depreciation	6,603
Year(s) Acquired	1997
Rogers Ave [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Rogers Ave
Location	San Jose, CA
Initial Cost to Company, Land	3,540
Initial Cost to Company, Buildings and Improvements	4,896
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	409
Gross Amount at Which Carried at December 31, 2012, Land	3,540
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	5,305
Gross Amount at Which Carried at December 31, 2012, Total	8,845
Accumulated Depreciation	1,982
Year(s) Acquired	2006
Doolittle Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Doolittle Business Park
Location	San Leandro, CA
Encumbrances	4,500
Initial Cost to Company, Land	3,929
Initial Cost to Company, Buildings and Improvements	6,231
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	180
Gross Amount at Which Carried at December 31, 2012, Land	3,929
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	6,411
Gross Amount at Which Carried at December 31, 2012, Total	10,340
Accumulated Depreciation	419
Year(s) Acquired	2011
San Ramon/Norris Canyon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	San Ramon/Norris Canyon
Location	San Ramon, CA
Initial Cost to Company, Land	1,486
Initial Cost to Company, Buildings and Improvements	3,642
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,189
Gross Amount at Which Carried at December 31, 2012, Land	1,486
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	4,831
Gross Amount at Which Carried at December 31, 2012, Total	6,317
Accumulated Depreciation	2,750
Year(s) Acquired	1997
Commerce Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Commerce Park
Location	Santa Clara, CA
Initial Cost to Company, Land	17,218
Initial Cost to Company, Buildings and Improvements	21,914
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,570
Gross Amount at Which Carried at December 31, 2012, Land	17,218
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	25,484
Gross Amount at Which Carried at December 31, 2012, Total	42,702
Accumulated Depreciation	13,739
Year(s) Acquired	2007
Santa Clara Tech Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Santa Clara Tech Park
Location	Santa Clara, CA
Initial Cost to Company, Land	7,673
Initial Cost to Company, Buildings and Improvements	15,645
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,551
Gross Amount at Which Carried at December 31, 2012, Land	7,673
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	19,196
Gross Amount at Which Carried at December 31, 2012, Total	26,869
Accumulated Depreciation	9,603
Year(s) Acquired	2000
Walsh At Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Walsh at Lafayette
Location	Santa Clara, CA
Encumbrances	19,300
Initial Cost to Company, Land	13,437
Initial Cost to Company, Buildings and Improvements	17,890
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	80
Gross Amount at Which Carried at December 31, 2012, Land	13,437
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	17,970
Gross Amount at Which Carried at December 31, 2012, Total	31,407
Accumulated Depreciation	2,048
Year(s) Acquired	2011
Airport Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Airport Blvd
Location	So. San Francisco, CA
Initial Cost to Company, Land	899
Initial Cost to Company, Buildings and Improvements	2,387
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	638
Gross Amount at Which Carried at December 31, 2012, Land	899
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	3,025
Gross Amount at Which Carried at December 31, 2012, Total	3,924
Accumulated Depreciation	1,672
Year(s) Acquired	1997
So. San Francisco/Produce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	So. San Francisco/Produce
Location	So. San Francisco, CA
Initial Cost to Company, Land	776
Initial Cost to Company, Buildings and Improvements	1,886
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	411
Gross Amount at Which Carried at December 31, 2012, Land	776
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	2,297
Gross Amount at Which Carried at December 31, 2012, Total	3,073
Accumulated Depreciation	1,267
Year(s) Acquired	1997
Kifer Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Kifer Industrial Park
Location	Sunnyvale, CA
Encumbrances	28,600
Initial Cost to Company, Land	13,227
Initial Cost to Company, Buildings and Improvements	37,874
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	15
Gross Amount at Which Carried at December 31, 2012, Land	13,227
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	37,889
Gross Amount at Which Carried at December 31, 2012, Total	51,116
Accumulated Depreciation	2,152
Year(s) Acquired	2011
Buena Park Industrial Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Buena Park Industrial Center
Location	Buena Park, CA
Initial Cost to Company, Land	3,245
Initial Cost to Company, Buildings and Improvements	7,703
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,147
Gross Amount at Which Carried at December 31, 2012, Land	3,245
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,850
Gross Amount at Which Carried at December 31, 2012, Total	13,095
Accumulated Depreciation	5,457
Year(s) Acquired	1997
Carson [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Carson
Location	Carson, CA
Initial Cost to Company, Land	990
Initial Cost to Company, Buildings and Improvements	2,496
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,330
Gross Amount at Which Carried at December 31, 2012, Land	990
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	3,826
Gross Amount at Which Carried at December 31, 2012, Total	4,816
Accumulated Depreciation	2,305
Year(s) Acquired	1997
Cerritos Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Cerritos Business Center
Location	Cerritos, CA
Initial Cost to Company, Land	4,218
Initial Cost to Company, Buildings and Improvements	10,273
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,524
Gross Amount at Which Carried at December 31, 2012, Land	4,218
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	13,797
Gross Amount at Which Carried at December 31, 2012, Total	18,015
Accumulated Depreciation	7,844
Year(s) Acquired	1997
Cerritos/Edwards [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Cerritos/Edwards
Location	Cerritos, CA
Initial Cost to Company, Land	450
Initial Cost to Company, Buildings and Improvements	1,217
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,193
Gross Amount at Which Carried at December 31, 2012, Land	450
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	2,410
Gross Amount at Which Carried at December 31, 2012, Total	2,860
Accumulated Depreciation	1,366
Year(s) Acquired	1997
Culver City [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Culver City
Location	Culver City, CA
Initial Cost to Company, Land	3,252
Initial Cost to Company, Buildings and Improvements	8,157
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,776
Gross Amount at Which Carried at December 31, 2012, Land	3,252
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	13,933
Gross Amount at Which Carried at December 31, 2012, Total	17,185
Accumulated Depreciation	8,332
Year(s) Acquired	1997
Corporate Pointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Corporate Pointe
Location	Irvine, CA
Initial Cost to Company, Land	6,876
Initial Cost to Company, Buildings and Improvements	18,519
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	6,174
Gross Amount at Which Carried at December 31, 2012, Land	6,876
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	24,693
Gross Amount at Which Carried at December 31, 2012, Total	31,569
Accumulated Depreciation	14,435
Year(s) Acquired	2000
Laguna Hills Commerce Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Laguna Hills Commerce Center
Location	Laguna Hills, CA
Initial Cost to Company, Land	16,261
Initial Cost to Company, Buildings and Improvements	39,559
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,341
Gross Amount at Which Carried at December 31, 2012, Land	16,261
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	43,900
Gross Amount at Which Carried at December 31, 2012, Total	60,161
Accumulated Depreciation	23,359
Year(s) Acquired	1997
Plaza Del Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Plaza Del Lago
Location	Laguna Hills, CA
Initial Cost to Company, Land	2,037
Initial Cost to Company, Buildings and Improvements	5,051
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,548
Gross Amount at Which Carried at December 31, 2012, Land	2,037
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	8,599
Gross Amount at Which Carried at December 31, 2012, Total	10,636
Accumulated Depreciation	5,470
Year(s) Acquired	1997
Canada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Canada
Location	Lake Forest, CA
Initial Cost to Company, Land	5,508
Initial Cost to Company, Buildings and Improvements	13,785
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,646
Gross Amount at Which Carried at December 31, 2012, Land	5,508
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	18,431
Gross Amount at Which Carried at December 31, 2012, Total	23,939
Accumulated Depreciation	10,410
Year(s) Acquired	1997
Monterey Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Monterey Park
Location	Monterey Park, CA
Initial Cost to Company, Land	3,078
Initial Cost to Company, Buildings and Improvements	7,862
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,420
Gross Amount at Which Carried at December 31, 2012, Land	3,078
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,282
Gross Amount at Which Carried at December 31, 2012, Total	12,360
Accumulated Depreciation	5,218
Year(s) Acquired	1997
Orange County Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Orange County Business Center
Location	Orange County, CA
Initial Cost to Company, Land	9,405
Initial Cost to Company, Buildings and Improvements	35,746
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	17,147
Gross Amount at Which Carried at December 31, 2012, Land	9,405
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	52,893
Gross Amount at Which Carried at December 31, 2012, Total	62,298
Accumulated Depreciation	36,846
Year(s) Acquired	2003
Orangewood [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Orangewood
Location	Orange County, CA
Initial Cost to Company, Land	2,637
Initial Cost to Company, Buildings and Improvements	12,291
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,003
Gross Amount at Which Carried at December 31, 2012, Land	2,637
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	15,294
Gross Amount at Which Carried at December 31, 2012, Total	17,931
Accumulated Depreciation	7,560
Year(s) Acquired	2003
Kearney Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Kearney Mesa
Location	San Diego, CA
Initial Cost to Company, Land	2,894
Initial Cost to Company, Buildings and Improvements	7,089
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,605
Gross Amount at Which Carried at December 31, 2012, Land	2,894
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,694
Gross Amount at Which Carried at December 31, 2012, Total	12,588
Accumulated Depreciation	5,542
Year(s) Acquired	1997
Lusk [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Lusk
Location	San Diego, CA
Initial Cost to Company, Land	5,711
Initial Cost to Company, Buildings and Improvements	14,049
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,240
Gross Amount at Which Carried at December 31, 2012, Land	5,711
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	19,289
Gross Amount at Which Carried at December 31, 2012, Total	25,000
Accumulated Depreciation	11,180
Year(s) Acquired	1997
Rose Canyon Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Rose Canyon Business Park
Location	San Diego, CA
Initial Cost to Company, Land	15,129
Initial Cost to Company, Buildings and Improvements	20,054
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,856
Gross Amount at Which Carried at December 31, 2012, Land	15,129
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	21,910
Gross Amount at Which Carried at December 31, 2012, Total	37,039
Accumulated Depreciation	9,566
Year(s) Acquired	2005
Signal Hill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Signal Hill
Location	Signal Hill, CA
Initial Cost to Company, Land	6,693
Initial Cost to Company, Buildings and Improvements	12,699
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,241
Gross Amount at Which Carried at December 31, 2012, Land	6,693
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	14,940
Gross Amount at Which Carried at December 31, 2012, Total	21,633
Accumulated Depreciation	6,979
Year(s) Acquired	1997/2006
Studio City/Ventura [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Studio City/Ventura
Location	Studio City, CA
Initial Cost to Company, Land	621
Initial Cost to Company, Buildings and Improvements	1,530
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	375
Gross Amount at Which Carried at December 31, 2012, Land	621
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,905
Gross Amount at Which Carried at December 31, 2012, Total	2,526
Accumulated Depreciation	1,113
Year(s) Acquired	1997
Torrance [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Torrance
Location	Torrance, CA
Initial Cost to Company, Land	2,318
Initial Cost to Company, Buildings and Improvements	6,069
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,665
Gross Amount at Which Carried at December 31, 2012, Land	2,318
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	8,734
Gross Amount at Which Carried at December 31, 2012, Total	11,052
Accumulated Depreciation	5,023
Year(s) Acquired	1997
Boca Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Boca Commerce
Location	Boca Raton, FL
Encumbrances	9,036
Initial Cost to Company, Land	7,795
Initial Cost to Company, Buildings and Improvements	9,258
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	917
Gross Amount at Which Carried at December 31, 2012, Land	7,795
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	10,175
Gross Amount at Which Carried at December 31, 2012, Total	17,970
Accumulated Depreciation	3,295
Year(s) Acquired	2006
MICC [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	MICC
Location	Miami, FL
Initial Cost to Company, Land	89,529
Initial Cost to Company, Buildings and Improvements	105,370
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	35,318
Gross Amount at Which Carried at December 31, 2012, Land	89,529
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	140,688
Gross Amount at Which Carried at December 31, 2012, Total	230,217
Accumulated Depreciation	69,205
Year(s) Acquired	2003/2011
Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Wellington
Location	Wellington, FL
Encumbrances	9,066
Initial Cost to Company, Land	10,845
Initial Cost to Company, Buildings and Improvements	18,560
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,307
Gross Amount at Which Carried at December 31, 2012, Land	10,845
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	19,867
Gross Amount at Which Carried at December 31, 2012, Total	30,712
Accumulated Depreciation	5,952
Year(s) Acquired	2006
Ammendale [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Ammendale
Location	Beltsville, MD
Initial Cost to Company, Land	4,278
Initial Cost to Company, Buildings and Improvements	18,380
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	9,511
Gross Amount at Which Carried at December 31, 2012, Land	4,278
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	27,891
Gross Amount at Which Carried at December 31, 2012, Total	32,169
Accumulated Depreciation	17,612
Year(s) Acquired	1998
Gaithersburg/Christopher [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Gaithersburg/Christopher
Location	Gaithersburg, MD
Initial Cost to Company, Land	475
Initial Cost to Company, Buildings and Improvements	1,203
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	535
Gross Amount at Which Carried at December 31, 2012, Land	475
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,738
Gross Amount at Which Carried at December 31, 2012, Total	2,213
Accumulated Depreciation	1,063
Year(s) Acquired	1997
Metro Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Metro Park
Location	Rockville, MD
Initial Cost to Company, Land	33,995
Initial Cost to Company, Buildings and Improvements	94,463
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	33,125
Gross Amount at Which Carried at December 31, 2012, Land	33,995
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	127,588
Gross Amount at Which Carried at December 31, 2012, Total	161,583
Accumulated Depreciation	69,333
Year(s) Acquired	2001
Parklawn Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Parklawn Business Park
Location	Rockville, MD
Initial Cost to Company, Land	3,387
Initial Cost to Company, Buildings and Improvements	19,628
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,500
Gross Amount at Which Carried at December 31, 2012, Land	3,387
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	22,128
Gross Amount at Which Carried at December 31, 2012, Total	25,515
Accumulated Depreciation	3,755
Year(s) Acquired	2010
Shady Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Shady Grove
Location	Rockville, MD
Initial Cost to Company, Land	5,372
Initial Cost to Company, Buildings and Improvements	50,727
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	6,614
Gross Amount at Which Carried at December 31, 2012, Land	5,372
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	57,341
Gross Amount at Which Carried at December 31, 2012, Total	62,713
Accumulated Depreciation	8,745
Year(s) Acquired	2010
Westech Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Westech Business Park
Location	Silver Spring, MD
Initial Cost to Company, Land	25,261
Initial Cost to Company, Buildings and Improvements	74,572
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	10,012
Gross Amount at Which Carried at December 31, 2012, Land	25,261
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	84,584
Gross Amount at Which Carried at December 31, 2012, Total	109,845
Accumulated Depreciation	40,437
Year(s) Acquired	2006
Cornell Oaks [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Cornell Oaks
Location	Beaverton, OR
Initial Cost to Company, Land	20,616
Initial Cost to Company, Buildings and Improvements	63,235
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	17,667
Gross Amount at Which Carried at December 31, 2012, Land	20,616
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	80,902
Gross Amount at Which Carried at December 31, 2012, Total	101,518
Accumulated Depreciation	41,662
Year(s) Acquired	2001
Creekside [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Creekside
Location	Beaverton, OR
Initial Cost to Company, Land	15,007
Initial Cost to Company, Buildings and Improvements	47,125
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	22,022
Gross Amount at Which Carried at December 31, 2012, Land	15,007
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	69,147
Gross Amount at Which Carried at December 31, 2012, Total	84,154
Accumulated Depreciation	42,633
Year(s) Acquired	1998/2000
Milwaukie [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Milwaukie
Location	Milwaukie, OR
Initial Cost to Company, Land	1,125
Initial Cost to Company, Buildings and Improvements	2,857
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,613
Gross Amount at Which Carried at December 31, 2012, Land	1,125
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	4,470
Gross Amount at Which Carried at December 31, 2012, Total	5,595
Accumulated Depreciation	2,627
Year(s) Acquired	1997
Empire Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Empire Commerce
Location	Dallas, TX
Initial Cost to Company, Land	304
Initial Cost to Company, Buildings and Improvements	1,545
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	814
Gross Amount at Which Carried at December 31, 2012, Land	304
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	2,359
Gross Amount at Which Carried at December 31, 2012, Total	2,663
Accumulated Depreciation	1,545
Year(s) Acquired	1998
Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Northgate
Location	Dallas, TX
Initial Cost to Company, Land	1,274
Initial Cost to Company, Buildings and Improvements	5,505
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,731
Gross Amount at Which Carried at December 31, 2012, Land	1,274
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,236
Gross Amount at Which Carried at December 31, 2012, Total	10,510
Accumulated Depreciation	5,428
Year(s) Acquired	1998
Westwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Westwood Business Park
Location	Farmers Branch, TX
Initial Cost to Company, Land	941
Initial Cost to Company, Buildings and Improvements	6,884
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,503
Gross Amount at Which Carried at December 31, 2012, Land	941
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	8,387
Gross Amount at Which Carried at December 31, 2012, Total	9,328
Accumulated Depreciation	4,026
Year(s) Acquired	2003
Eastgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Eastgate
Location	Garland, TX
Initial Cost to Company, Land	480
Initial Cost to Company, Buildings and Improvements	1,203
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	568
Gross Amount at Which Carried at December 31, 2012, Land	480
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,771
Gross Amount at Which Carried at December 31, 2012, Total	2,251
Accumulated Depreciation	1,045
Year(s) Acquired	1997
NFTZ [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	NFTZ (1)	[1]
Location	Irving, TX	[1]
Initial Cost to Company, Land	1,517	[1]
Initial Cost to Company, Buildings and Improvements	6,499	[1]
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,836	[1]
Gross Amount at Which Carried at December 31, 2012, Land	1,517	[1]
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	8,335	[1]
Gross Amount at Which Carried at December 31, 2012, Total	9,852	[1]
Accumulated Depreciation	5,353	[1]
Year(s) Acquired	1998	[1]
Royal Tech [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Royal Tech
Location	Irving, TX
Initial Cost to Company, Land	13,989
Initial Cost to Company, Buildings and Improvements	54,113
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	19,760
Gross Amount at Which Carried at December 31, 2012, Land	13,989
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	73,873
Gross Amount at Which Carried at December 31, 2012, Total	87,862
Accumulated Depreciation	40,504
Year(s) Acquired	1998-2000/2011
La Prada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	La Prada
Location	Mesquite, TX
Initial Cost to Company, Land	495
Initial Cost to Company, Buildings and Improvements	1,235
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	629
Gross Amount at Which Carried at December 31, 2012, Land	495
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,864
Gross Amount at Which Carried at December 31, 2012, Total	2,359
Accumulated Depreciation	1,102
Year(s) Acquired	1997
The Summit [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	The Summit
Location	Plano, TX
Initial Cost to Company, Land	1,536
Initial Cost to Company, Buildings and Improvements	6,654
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,674
Gross Amount at Which Carried at December 31, 2012, Land	1,536
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	10,328
Gross Amount at Which Carried at December 31, 2012, Total	11,864
Accumulated Depreciation	6,657
Year(s) Acquired	1998
Richardson/Business Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Richardson/Business Parkway
Location	Richardson, TX
Initial Cost to Company, Land	799
Initial Cost to Company, Buildings and Improvements	3,568
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,363
Gross Amount at Which Carried at December 31, 2012, Land	799
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	5,931
Gross Amount at Which Carried at December 31, 2012, Total	6,730
Accumulated Depreciation	3,881
Year(s) Acquired	1998
Ben White [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Ben White
Location	Austin, TX
Initial Cost to Company, Land	1,550
Initial Cost to Company, Buildings and Improvements	7,015
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,802
Gross Amount at Which Carried at December 31, 2012, Land	1,550
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	8,817
Gross Amount at Which Carried at December 31, 2012, Total	10,367
Accumulated Depreciation	4,611
Year(s) Acquired	1998
Lamar Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Lamar Business Park
Location	Austin, TX
Initial Cost to Company, Land	2,528
Initial Cost to Company, Buildings and Improvements	6,596
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,978
Gross Amount at Which Carried at December 31, 2012, Land	2,528
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	10,574
Gross Amount at Which Carried at December 31, 2012, Total	13,102
Accumulated Depreciation	7,944
Year(s) Acquired	1997
McKalla [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	McKalla
Location	Austin, TX
Initial Cost to Company, Land	1,945
Initial Cost to Company, Buildings and Improvements	13,212
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,805
Gross Amount at Which Carried at December 31, 2012, Land	1,945
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	15,017
Gross Amount at Which Carried at December 31, 2012, Total	16,962
Accumulated Depreciation	5,043
Year(s) Acquired	1998/2012
Rutland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Rutland
Location	Austin, TX
Initial Cost to Company, Land	2,022
Initial Cost to Company, Buildings and Improvements	9,397
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,618
Gross Amount at Which Carried at December 31, 2012, Land	2,022
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	13,015
Gross Amount at Which Carried at December 31, 2012, Total	15,037
Accumulated Depreciation	6,515
Year(s) Acquired	1998/1999
Waterford [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Waterford
Location	Austin, TX
Initial Cost to Company, Land	2,108
Initial Cost to Company, Buildings and Improvements	9,649
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,206
Gross Amount at Which Carried at December 31, 2012, Land	2,108
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,855
Gross Amount at Which Carried at December 31, 2012, Total	14,963
Accumulated Depreciation	7,637
Year(s) Acquired	1999
Braker Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Braker Business Park
Location	Austin, TX
Initial Cost to Company, Land	1,874
Initial Cost to Company, Buildings and Improvements	13,990
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	919
Gross Amount at Which Carried at December 31, 2012, Land	1,874
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	14,909
Gross Amount at Which Carried at December 31, 2012, Total	16,783
Accumulated Depreciation	3,213
Year(s) Acquired	2010
McNeil [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	McNeil
Location	Austin, TX
Initial Cost to Company, Land	2,314
Initial Cost to Company, Buildings and Improvements	17,044
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,512
Gross Amount at Which Carried at December 31, 2012, Land	2,314
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	18,556
Gross Amount at Which Carried at December 31, 2012, Total	20,870
Accumulated Depreciation	4,224
Year(s) Acquired	1999/2010/2012
Mopac Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Mopac Business Park
Location	Austin, TX
Initial Cost to Company, Land	719
Initial Cost to Company, Buildings and Improvements	3,579
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	330
Gross Amount at Which Carried at December 31, 2012, Land	719
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	3,909
Gross Amount at Which Carried at December 31, 2012, Total	4,628
Accumulated Depreciation	791
Year(s) Acquired	2010
Southpark Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Southpark Business Park
Location	Austin, TX
Initial Cost to Company, Land	1,266
Initial Cost to Company, Buildings and Improvements	9,882
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	748
Gross Amount at Which Carried at December 31, 2012, Land	1,266
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	10,630
Gross Amount at Which Carried at December 31, 2012, Total	11,896
Accumulated Depreciation	2,197
Year(s) Acquired	2010
Bren Mar [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Bren Mar
Location	Alexandria, VA
Initial Cost to Company, Land	2,197
Initial Cost to Company, Buildings and Improvements	5,380
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,670
Gross Amount at Which Carried at December 31, 2012, Land	2,197
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,050
Gross Amount at Which Carried at December 31, 2012, Total	11,247
Accumulated Depreciation	5,358
Year(s) Acquired	1997
Eisenhower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Eisenhower
Location	Alexandria, VA
Initial Cost to Company, Land	1,440
Initial Cost to Company, Buildings and Improvements	3,635
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,372
Gross Amount at Which Carried at December 31, 2012, Land	1,440
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	6,007
Gross Amount at Which Carried at December 31, 2012, Total	7,447
Accumulated Depreciation	3,920
Year(s) Acquired	1997
Beaumont [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Beaumont
Location	Chantilly, VA
Initial Cost to Company, Land	4,736
Initial Cost to Company, Buildings and Improvements	11,051
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,480
Gross Amount at Which Carried at December 31, 2012, Land	4,736
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,531
Gross Amount at Which Carried at December 31, 2012, Total	17,267
Accumulated Depreciation	5,431
Year(s) Acquired	2006
Dulles South/Sullyfield [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Dulles South/Sullyfield
Location	Chantilly, VA
Initial Cost to Company, Land	1,373
Initial Cost to Company, Buildings and Improvements	6,810
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	2,645
Gross Amount at Which Carried at December 31, 2012, Land	1,373
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,455
Gross Amount at Which Carried at December 31, 2012, Total	10,828
Accumulated Depreciation	5,342
Year(s) Acquired	1999
Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Lafayette
Location	Chantilly, VA
Initial Cost to Company, Land	1,680
Initial Cost to Company, Buildings and Improvements	13,398
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,218
Gross Amount at Which Carried at December 31, 2012, Land	1,680
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	17,616
Gross Amount at Which Carried at December 31, 2012, Total	19,296
Accumulated Depreciation	10,731
Year(s) Acquired	1999/2000
Park East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Park East
Location	Chantilly, VA
Initial Cost to Company, Land	3,851
Initial Cost to Company, Buildings and Improvements	18,029
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	9,252
Gross Amount at Which Carried at December 31, 2012, Land	3,851
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	27,281
Gross Amount at Which Carried at December 31, 2012, Total	31,132
Accumulated Depreciation	13,682
Year(s) Acquired	1999
Fair Oaks Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Fair Oaks Business Park
Location	Fairfax, VA
Initial Cost to Company, Land	13,598
Initial Cost to Company, Buildings and Improvements	36,232
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,181
Gross Amount at Which Carried at December 31, 2012, Land	13,598
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	41,413
Gross Amount at Which Carried at December 31, 2012, Total	55,011
Accumulated Depreciation	19,935
Year(s) Acquired	2004/2007
Prosperity Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Prosperity Business Campus
Location	Fairfax, VA
Initial Cost to Company, Land	23,147
Initial Cost to Company, Buildings and Improvements	67,575
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	24,636
Gross Amount at Which Carried at December 31, 2012, Land	23,147
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	92,211
Gross Amount at Which Carried at December 31, 2012, Total	115,358
Accumulated Depreciation	48,017
Year(s) Acquired	2001
Monroe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Monroe
Location	Herndon, VA
Initial Cost to Company, Land	6,737
Initial Cost to Company, Buildings and Improvements	18,911
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	9,207
Gross Amount at Which Carried at December 31, 2012, Land	6,737
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	28,118
Gross Amount at Which Carried at December 31, 2012, Total	34,855
Accumulated Depreciation	17,080
Year(s) Acquired	1997/1999
Gunston [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Gunston
Location	Lorton, VA
Initial Cost to Company, Land	4,146
Initial Cost to Company, Buildings and Improvements	17,872
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,489
Gross Amount at Which Carried at December 31, 2012, Land	4,146
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	22,361
Gross Amount at Which Carried at December 31, 2012, Total	26,507
Accumulated Depreciation	12,634
Year(s) Acquired	1998
Westpark Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Westpark Business Campus
Location	McLean, VA
Initial Cost to Company, Land	53,882
Initial Cost to Company, Buildings and Improvements	111,253
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	15,612
Gross Amount at Which Carried at December 31, 2012, Land	53,882
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	126,865
Gross Amount at Which Carried at December 31, 2012, Total	180,747
Accumulated Depreciation	15,787
Year(s) Acquired	2010/2011
Alban Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Alban Road
Location	Springfield, VA
Initial Cost to Company, Land	1,935
Initial Cost to Company, Buildings and Improvements	4,736
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,618
Gross Amount at Which Carried at December 31, 2012, Land	1,935
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	9,354
Gross Amount at Which Carried at December 31, 2012, Total	11,289
Accumulated Depreciation	6,044
Year(s) Acquired	1997
I-95 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	I-95
Location	Springfield, VA
Initial Cost to Company, Land	3,535
Initial Cost to Company, Buildings and Improvements	15,672
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	10,093
Gross Amount at Which Carried at December 31, 2012, Land	3,535
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	25,765
Gross Amount at Which Carried at December 31, 2012, Total	29,300
Accumulated Depreciation	17,657
Year(s) Acquired	2000
Northpointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Northpointe
Location	Sterling, VA
Initial Cost to Company, Land	2,767
Initial Cost to Company, Buildings and Improvements	8,778
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	4,026
Gross Amount at Which Carried at December 31, 2012, Land	2,767
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	12,804
Gross Amount at Which Carried at December 31, 2012, Total	15,571
Accumulated Depreciation	8,512
Year(s) Acquired	1997/1998
Shaw Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Shaw Road
Location	Sterling, VA
Initial Cost to Company, Land	2,969
Initial Cost to Company, Buildings and Improvements	10,008
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	3,768
Gross Amount at Which Carried at December 31, 2012, Land	2,969
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	13,776
Gross Amount at Which Carried at December 31, 2012, Total	16,745
Accumulated Depreciation	9,254
Year(s) Acquired	1998
Tysons Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Tysons Corporate Center
Location	Vienna, VA
Initial Cost to Company, Land	9,885
Initial Cost to Company, Buildings and Improvements	25,302
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	7,738
Gross Amount at Which Carried at December 31, 2012, Land	9,885
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	33,040
Gross Amount at Which Carried at December 31, 2012, Total	42,925
Accumulated Depreciation	4,889
Year(s) Acquired	2010
Woodbridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Woodbridge
Location	Woodbridge, VA
Initial Cost to Company, Land	1,350
Initial Cost to Company, Buildings and Improvements	3,398
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,623
Gross Amount at Which Carried at December 31, 2012, Land	1,350
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	5,021
Gross Amount at Which Carried at December 31, 2012, Total	6,371
Accumulated Depreciation	3,087
Year(s) Acquired	1997
212th Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	212th Business Park
Location	Kent, WA
Initial Cost to Company, Land	19,573
Initial Cost to Company, Buildings and Improvements	17,695
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	1,489
Gross Amount at Which Carried at December 31, 2012, Land	19,573
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	19,184
Gross Amount at Which Carried at December 31, 2012, Total	38,757
Accumulated Depreciation	461
Year(s) Acquired	2012
Overlake [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Overlake
Location	Redmond, WA
Initial Cost to Company, Land	27,761
Initial Cost to Company, Buildings and Improvements	49,353
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	5,568
Gross Amount at Which Carried at December 31, 2012, Land	27,761
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	54,921
Gross Amount at Which Carried at December 31, 2012, Total	82,682
Accumulated Depreciation	26,465
Year(s) Acquired	2007
Renton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Description	Renton
Location	Renton, WA
Initial Cost to Company, Land	330
Initial Cost to Company, Buildings and Improvements	889
Cost Capitalized Subsequent to Acquisition, Buildings and Improvements	517
Gross Amount at Which Carried at December 31, 2012, Land	330
Gross Amount at Which Carried at December 31, 2012, Buildings and Improvements	1,406
Gross Amount at Which Carried at December 31, 2012, Total	1,736
Accumulated Depreciation	$ 840
Year(s) Acquired	1997
Las Colinas, Texas Property I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Ground leases expiration, extension option period (in years)	10 years
Las Colinas, Texas Property II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Ground leases expiration, extension option period (in years)	10 years
Minimum [Member] | Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Corporate/Metro Park Phoenix [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Tempe/McKellips [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | University [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Concord Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Bayview Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Christy Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Industrial Drive Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Bay Center Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Cabot Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Diablo Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Eden Landing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Hayward Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Huntwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Parkway Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Dixon Landing Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Monterey/Calle [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Port Of Oakland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Northpointe Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Sacramento/Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Charcot Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Las Plumas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Little Orchard Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Montague Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Oakland Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Rogers Ave [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Doolittle Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | San Ramon/Norris Canyon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Commerce Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Santa Clara Tech Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Walsh At Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Airport Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | So. San Francisco/Produce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Kifer Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Buena Park Industrial Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Carson [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Cerritos Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Cerritos/Edwards [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Culver City [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Corporate Pointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Laguna Hills Commerce Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Plaza Del Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Canada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Monterey Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Orange County Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Orangewood [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Kearney Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Lusk [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Rose Canyon Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Signal Hill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Studio City/Ventura [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Torrance [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Boca Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | MICC [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Ammendale [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Gaithersburg/Christopher [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Metro Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Parklawn Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Shady Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Westech Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Cornell Oaks [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Creekside [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Milwaukie [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Empire Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Westwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Eastgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | NFTZ [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Royal Tech [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | La Prada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | The Summit [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Richardson/Business Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Ben White [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Lamar Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | McKalla [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Rutland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Waterford [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Braker Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | McNeil [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Mopac Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Southpark Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Bren Mar [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Eisenhower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Beaumont [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Dulles South/Sullyfield [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Park East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Fair Oaks Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Prosperity Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Monroe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Gunston [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Westpark Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Alban Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | I-95 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Northpointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Shaw Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Tysons Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Woodbridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | 212th Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Overlake [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Minimum [Member] | Renton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	5 years
Maximum [Member] | Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Corporate/Metro Park Phoenix [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Tempe/McKellips [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | University [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Concord Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Bayview Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Christy Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Industrial Drive Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Bay Center Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Cabot Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Diablo Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Eden Landing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Hayward Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Huntwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Parkway Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Dixon Landing Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Monterey/Calle [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Port Of Oakland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Northpointe Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Sacramento/Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Charcot Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Las Plumas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Little Orchard Distribution Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Montague Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Oakland Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Rogers Ave [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Doolittle Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | San Ramon/Norris Canyon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Commerce Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Santa Clara Tech Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Walsh At Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Airport Blvd [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | So. San Francisco/Produce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Kifer Industrial Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Buena Park Industrial Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Carson [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Cerritos Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Cerritos/Edwards [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Culver City [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Corporate Pointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Laguna Hills Commerce Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Plaza Del Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Canada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Monterey Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Orange County Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Orangewood [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Kearney Mesa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Lusk [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Rose Canyon Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Signal Hill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Studio City/Ventura [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Torrance [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Boca Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | MICC [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Ammendale [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Gaithersburg/Christopher [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Metro Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Parklawn Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Shady Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Westech Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Cornell Oaks [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Creekside [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Milwaukie [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Empire Commerce [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Northgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Westwood Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Eastgate [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | NFTZ [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Royal Tech [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | La Prada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | The Summit [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Richardson/Business Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Ben White [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Lamar Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | McKalla [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Rutland [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Waterford [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Braker Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | McNeil [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Mopac Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Southpark Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Bren Mar [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Eisenhower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Beaumont [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Dulles South/Sullyfield [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Lafayette [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Park East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Fair Oaks Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Prosperity Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Monroe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Gunston [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Westpark Business Campus [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Alban Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | I-95 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Northpointe [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Shaw Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Tysons Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Woodbridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | 212th Business Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Overlake [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years
Maximum [Member] | Renton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives (Years)	30 years

[1] The Company owns two properties that are subject to ground leases in Las Colinas, Texas, expiring in 2019 and 2020, each with one 10 year extension option.

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Related Party Transactions (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010	Feb. 09, 2011
Related Party Transactions [Abstract]
Royalty-free license agreement written notice of termination period minimum (in months)	6 months
Property management contract term (in years)	7 years
Extended property management contract period (in years)	1 year
Management fee revenues	$ 649,000	$ 684,000	$ 672,000
Number of assets owned that are maintained by Public Storage	2
Property management contract written notice of termination period minimum (in days)	60 days
Management fee expenses	55,000	52,000	48,000
Administrative services costs	441,000	442,000	543,000
Due from related parties	243,000	205,000
Date of note payable with affiliate	Feb. 09, 2011
Original note payable to affiliate				121,000,000
Loan maturity date	Aug. 09, 2011
Spread over LIBOR for note payable	1.10%			0.85%
Interest expense, related party		$ 664,000

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Summary Of Significant Accounting Policies (Calculation Of Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary Of Significant Accounting Policies [Abstract]
Net income allocable to common shareholders	$ 9,760	$ 5,172	$ 1,410	$ 3,467	$ 8,801	$ 15,444	$ 11,374	$ 16,562	$ 19,805	$ 52,162	$ 38,959
Basic weighted average common shares outstanding									24,234	24,516	24,546
Net effect of dilutive stock compensation - based on treasury stock method using average market price									89	83	141
Diluted weighted average common shares outstanding									24,323	24,599	24,687
Net income per common share - Basic	$ 0.40	$ 0.21	$ 0.06	$ 0.14	$ 0.36	$ 0.63	$ 0.46	$ 0.67	$ 0.82	$ 2.13	$ 1.59
Net income per common share - Diluted	$ 0.40	$ 0.21	$ 0.06	$ 0.14	$ 0.36	$ 0.63	$ 0.46	$ 0.67	$ 0.81	$ 2.12	$ 1.58

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Mortgage Notes Payable (Tables)

12 Months Ended

Dec. 31, 2012

Mortgage Notes Payable [Abstract]

Schedule Of Mortgage Notes Payable

		December 31,		December 31,
		2012		2011
5.45% mortgage note, secured by 4.8 million square feet of
commercial properties with a net book value of $448.4 million,
interest payable monthly, due December, 2016	$	250,000	$	250,000
5.52% mortgage note, secured by one commercial property with a
net book value of $14.7 million, principal and interest payable
monthly, repaid January, 2013		9,036		9,311
5.68% mortgage note, secured by one commercial property with a
net book value of $16.4 million, principal and interest payable
monthly, repaid January, 2013		9,066		9,337
5.73% mortgage note, repaid November, 2012		—		13,436
Total	$	268,102	$	282,084

Mortgage Notes Payable Maturity Period

2013	$	18,102
2014		—
2015		—
2016		250,000
Total	$	268,102

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Stock Compensation (Narrative) (Details) (USD $)	12 Months Ended														1 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2012 Certain Restricted Stock [Member]	Dec. 31, 2012 Performance-Based Restricted Stock Unit Program [Member] item	Dec. 31, 2012 2003 Plan [Member]	Dec. 31, 2012 2012 Plan [Member]	Feb. 20, 2012 2012 Plan [Member]	Apr. 30, 2012 Retirement Plan For Two Directors [Member]	Jan. 31, 2011 Retirement Plan For Non-Employee Directors [Member]	Dec. 31, 2012 Retirement Plan For Non-Employee Directors [Member]	Dec. 31, 2011 Retirement Plan For Non-Employee Directors [Member]	Dec. 31, 2010 Retirement Plan For Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares covered under Stock Option and Incentive Plan												1,500,000		1,000,000
Vesting period (in years)							6 years			3 years		5 years	5 years
Vesting percentage, year one							0.00%			33.30%
Vesting percentage, year two							20.00%			33.30%
Vesting percentage, year three							20.00%			33.30%
Vesting percentage, year four							20.00%
Vesting percentage, year five							20.00%
Vesting percentage, year six							20.00%
Expiration period (in years)												10 years	10 years
Weighted average grant date fair value of options granted				$ 4.85	$ 5.38	$ 6.08
Dividend yield				2.60%	2.90%	3.30%
Expected volatility				13.40%	13.90%	17.50%
Expected life (in years)				5 years	5 years	5 years
Risk-free interest rate				0.90%	1.70%	2.40%
Weighted average grant date fair value of stock granted	$ 65.14	$ 51.63	$ 54.44				$ 65.14	$ 51.63	$ 54.44
Options and restricted stock units authorized to grant	975,000
Length of Restricted Stock Unit program (in years)											4 years
Number of annual vesting installments beginning from one year from the date of award											3
Vesting begins after number of years from award date											1 year
Maximum number of shares issued upon retirement																	7,000	5,000
Approximate number of restricted stock units granted per tear, maximum											38,449
Cumulative number of restricted stock units granted											312,220
Compensation expense											$ 3,900,000						$ 287,000	$ 559,000	$ 153,000
Stock options expense				419,000	486,000	509,000
Restricted stock units expense							4,700,000	920,000	1,500,000
Unamortized compensation expense				979,000			23,800,000				21,600,000						1,200,000	514,000	339,000
Weighted average recognized period of unamortized compensation expenses (in years)				2 years 7 months 6 days			5 years 9 months 18 days
Exercise of stock options, shares	143,043	24,600	243,936	143,043	24,600	243,936
Proceeds from the exercise of stock options	5,907,000	1,050,000	7,783,000
Aggregate intrinsic value of the stock options exercised				3,400,000	457,000	5,300,000
Number of units, vested	20,094	29,890	44,857				20,094	29,890	44,857
Aggregate fair value of the shares vested							1,300,000	1,700,000	2,400,000
Shares approved for issuance																	70,000
Number of shares granted for each year served																	1,000
Stock compensation, net, shares							13,248	18,907	27,732						14,000	5,000
Aggregate fair value of shares issued															$ 956,000	$ 290,000

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Mortgage Notes Payable (Schedule Of Mortgage Notes Payable) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 sqft	Dec. 31, 2011
Debt Instrument [Line Items]
Mortgage notes payable, carrying amount	$ 268,102,000	$ 282,084,000
5.45% Mortgage Note [Member]
Debt Instrument [Line Items]
Interest rate	5.45%
Net book value of secured property	448,400,000
Mortgage note due date	Dec. 01, 2016
Mortgage notes payable, carrying amount	250,000,000	250,000,000
Secured by square feet of real estate facilities	4,800,000
5.52% Mortgage Note [Member]
Debt Instrument [Line Items]
Interest rate	5.52%
Net book value of secured property	14,700,000
Mortgage note repayment date	Jan. 01, 2013
Mortgage notes payable, carrying amount	9,036,000	9,311,000
Secured by number of real estate facilities	1
5.68% Mortgage Note [Member]
Debt Instrument [Line Items]
Interest rate	5.68%
Net book value of secured property	16,400,000
Mortgage note repayment date	Jan. 01, 2013
Mortgage notes payable, carrying amount	9,066,000	9,337,000
Secured by number of real estate facilities	1
5.73% Mortgage Note [Member]
Debt Instrument [Line Items]
Interest rate	5.73%
Mortgage note repayment date	Nov. 01, 2012
Mortgage notes payable, carrying amount		$ 13,436,000

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Real Estate Facilities (Summary Of Unaudited Pro Forma Portfolio Acquisition) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Real Estate Facilities [Abstract]
Pro Forma Revenues	$ 336,680	$ 317,770
Pro Forma Net income	$ 95,595	$ 91,088
Basic	$ 1.91	$ 1.24
Diluted	$ 1.90	$ 1.24

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Stock Compensation (Nonvested Restricted Stock Units) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation and Retirement Disclosure [Abstract]
Number of Units, Nonvested	59,224	85,674	119,091
Number of Units, Granted	17,800	8,700	13,900
Number of Units, Vested	(20,094)	(29,890)	(44,857)
Number of Units, Forfeited	(3,840)	(5,260)	(2,460)
Number of Units, Nonvested	53,090	59,224	85,674
Weighted Average Grant Date Fair Value, Nonvested	$ 52.24	$ 53.60	$ 53.64
Weighted Average Grant Date Fair Value, Granted	$ 65.14	$ 51.63	$ 54.44
Weighted Average Grant Date Fair Value, Vested	$ 51.36	$ 55.88	$ 53.84
Weighted Average Grant Date Fair Value, Forfeited	$ 53.95	$ 52.70	$ 55.90
Weighted Average Grant Date Fair Value, Nonvested	$ 55.69	$ 52.24	$ 53.60

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Shareholders' Equity (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010	Oct. 09, 2012 Series P [Member]	Dec. 31, 2012 Series P [Member]	Dec. 31, 2011 Series P [Member]	Sep. 14, 2012 Series U [Member]	Dec. 31, 2012 Series U [Member]	Dec. 31, 2012 Series H And I [Member]	Jun. 15, 2012 Series H [Member]	Dec. 31, 2012 Series H [Member]	Dec. 31, 2011 Series H [Member]	Jun. 15, 2012 Series I [Member]	Dec. 31, 2012 Series I [Member]	Dec. 31, 2011 Series I [Member]	May 14, 2012 Series T [Member]	Dec. 31, 2012 Series T [Member]	Feb. 29, 2012 Series M [Member]	Dec. 31, 2012 Series M [Member]	Dec. 31, 2011 Series M [Member]	Feb. 29, 2012 Series O [Member]	Dec. 31, 2012 Series O [Member]	Dec. 31, 2011 Series O [Member]	Dec. 31, 2012 Series O&M [Member]	Jan. 18, 2012 Series S [Member]	Dec. 31, 2012 Series S [Member]	Oct. 15, 2010 Series R [Member]	Dec. 31, 2012 Series R [Member]	Dec. 31, 2011 Series R [Member]	Nov. 08, 2010 Series L [Member]	Dec. 31, 2012 Series L [Member]	Dec. 31, 2010 Series L [Member]	Jun. 07, 2010 Series K [Member]	Dec. 31, 2012 Series K [Member]	Dec. 31, 2010 Series K [Member]
Class of Stock [Line Items]
Redemption date				Oct. 09, 2012	Jan. 01, 2012			Sep. 01, 2017	Jun. 15, 2012		Jan. 01, 2009			Apr. 01, 2009			May 01, 2017		May 01, 2010			Jun. 01, 2011		Feb. 01, 2012		Jan. 01, 2017		Oct. 01, 2015			Nov. 08, 2010			Jun. 07, 2010
Cumulative preferred stock, dividend rate				6.70%	6.70%		5.75%	5.75%		7.00%	7.00%		6.875%	6.875%		6.00%	6.00%	7.20%	7.20%		7.375%	7.375%			6.45%	6.45%	6.875%	6.875%		7.60%			7.95%
Redemption/repurchase of preferred stock	$ 523,546,000		$ 102,500,000	$ 132,300,000						$ 158,500,000			$ 68,600,000					$ 79,600,000			$ 84,600,000									$ 48,400,000			$ 54,100,000
Redeemed over carrying amount	(17,167,000)		(3,484,000)		3,800,000				8,100,000															5,300,000								1,600,000			1,900,000
Issuance Date					January, 2007			September 14, 2012			January & October, 2004			April, 2004			May 14, 2012		May, 2005			June & August, 2006				January 18, 2012		October 15, 2010
Proceeds from issuance of depositary shares	885,000,000	598,546,000				132,250,000	230,000,000	230,000,000				158,520,000			68,626,000	350,000,000	350,000,000			79,550,000			84,600,000		230,000,000	230,000,000	75,000,000	75,000,000	75,000,000
Depositary shares issued							9,200,000									14,000,000									9,200,000		3,000,000
Depository shares conversion ratio to preferred share							0.10%									0.10%									0.10%		0.10%
Depositary shares issued price per share							$ 25.00									$ 25.00									$ 25.00		$ 25.00
Distributions recorded to preferred shareholders	51,969,000	41,799,000	42,730,000
Number of quarterly dividends in arrearage before preferred shareholders can elect additional board members	6
Number of additional board members the preferred shareholders can elect in the case of an excess arrearage of quarterly dividends	2
Dividends in arrears	0
Redeemable preferred stock, redemption price per share	$ 25.00
Preferred stock, aggregate deferred issuance costs outstanding	$ 28,100,000	$ 19,700,000

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Real Estate Facilities

12 Months Ended

Dec. 31, 2012

Real Estate Facilities [Abstract]

Real Estate Facilities

3. Real estate facilities

     The activity in real estate facilities for the years ended December 31, 2012, 2011, and 2010 is as follows (in thousands):

				Buildings and			Accumulated
		Land		Equipment			Depreciation			Total
Balances at December 31, 2009	$	491,176	$	1,517,596		$	(702,263	)	$	1,306,509
Acquisition of real estate facilities		71,142		223,428			—			294,570
Capital improvements, net		—		40,378			—			40,378
Disposals		—		(9,237	)		9,237			—
Depreciation expense		—		—			(78,868	)		(78,868	)
Transfer to properties held for
disposition		—		(160	)		446			286
Balances at December 31, 2010		562,318		1,772,005			(771,448	)		1,562,875
Acquisition of real estate facilities		210,255		344,760			—			555,015
Capital improvements, net		—		49,624			—			49,624
Disposals		—		(10,150	)		10,150			—
Depreciation expense		—		—			(84,682	)		(84,682	)
Transfer to properties held for
disposition		—		(467	)		280			(187	)
Balances at December 31, 2011		772,573		2,155,772			(845,700	)		2,082,645
Acquisition of real estate facilities		20,779		30,621			—			51,400
Capital improvements, net		—		61,561			—			61,561
Disposals		—		(12,459	)		12,459			—
Depreciation expense		—		—			(109,494	)		(109,494	)
Transfer to properties held for
disposition		—		(47	)		96			49
Balances at December 31, 2012	$	793,352	$	2,235,448		$	(942,639	)	$	2,086,161

     The unaudited basis of real estate facilities for federal income tax purposes was approximately $2.0 billion at December 31, 2012. The Company had approximately 23.0% of its properties, in terms of net book value, encumbered by mortgage debt at December 31, 2012.

     On December 19, 2012, the Company acquired three multi-tenant flex buildings in Austin, Texas, aggregating 226,000 square feet, for a purchase price of $14.9 million. In connection with this purchase, the Company received a $592,000 credit for committed tenant improvements and lease commissions. On July 24, 2012, the Company acquired a 958,000 square foot industrial park consisting of eight single-story buildings located in Kent Valley, Washington, for a purchase price of $37.6 million. The Company incurred and expensed acquisition transaction costs of $350,000 for the year ended December 31, 2012.

     On December 20, 2011, the Company acquired a 5.3 million square foot industrial and flex portfolio located in the Northern California Bay Area (the "Portfolio"), with concentrations in Oakland, Hayward, Fremont, Milpitas, San Jose, Santa Clara and Sunnyvale, for an aggregate purchase price of $520.0 million. In connection with the transaction, the Company assumed a $250.0 million mortgage note described in Note 6. The Company also obtained a $250.0 million unsecured three-year term loan described in Note 5.

     The following table summarizes the assets acquired and liabilities assumed for the Portfolio acquisition during the year ended December 31, 2011 (in thousands):

Land	$	202,131
Buildings and improvements		320,210
Above-market in-place lease value		2,372
Below-market in-place lease value		(4,713	)
Total purchase price		520,000
Mortgage note assumed		(250,000	)
Net operating assets acquired and liabilities assumed		5,171
Total cash paid	$	275,171

     The results of operations of the Portfolio acquired have been included in the Company's consolidated financial statements since the date of acquisition of December 20, 2011. The unaudited pro forma data presented below assumes that the Portfolio acquisition occurred as of the beginning of the respective periods, and includes pro forma adjustments to (i) increase depreciation expense to reflect the Company's book basis for buildings and improvements acquired, (ii) increase amortization expense to reflect the above-market and below-market in-place lease value acquired, and (iii) increase interest expense to reflect the financing of the Portfolio acquisition related to the $250.0 million mortgage note assumption, borrowings from the term loan and credit facility. Rental income of $42.5 million and $1.2 million related to the Portfolio acquisition for the years ended December 31, 2012 and 2011, respectively, was reported in the Company's consolidated statements of income. Net losses of $7.2 million and $838,000 related to the Portfolio acquisition for the years end December 31, 2012 and 2011, respectively, were reported in the Company's consolidated statements of income. The net loss includes rental income less cost of operations, depreciation and mortgage note interest. The Company's unaudited pro forma results have been prepared for comparative purposes only and do not purport to be indicative of the results of operations that would have occurred had the Portfolio acquisition been consummated at the beginning of the periods presented (in thousands, except per share amounts):

		For The Years Ended
		December 31,
		2011		2010
Pro Forma Revenues	$	336,680	$	317,770
Pro Forma Net income	$	95,595	$	91,088
Pro Forma Net income per common share:
Basic	$	1.91	$	1.24
Diluted	$	1.90	$	1.24

     On October 13, 2011, the Company acquired an 80,000 square foot multi-tenant office building in Las Colinas, Texas, for $2.8 million. On August 19, 2011, the Company acquired a 46,000 square foot multi-tenant flex building located within its Miami International Commerce Center in Miami, Florida, for $3.5 million. On June 1, 2011, the Company acquired a 140,000 square foot multi-tenant office building, known as the Warren Building, located in Tysons Corner, Virginia, for $27.1 million. In connection with this purchase, the Company received a $298,000 credit for committed tenant improvements and leasing commissions. The Company incurred and expensed acquisition transaction costs of $3.1 million for the year ended December 31, 2011.

     On December 15, 2010, the Company acquired Westpark Business Campus, a seven-building multi-tenant office park aggregating 735,000 square feet in Tysons Corner, Virginia, for $140.0 million. In connection with this purchase, the Company received a $1.9 million credit for committed tenant improvements. On July 30, 2010, the Company acquired a two-building multi-tenant office park, known as Tysons Corporate Center, aggregating 270,000 square feet in Tysons Corner, Virginia, for $35.4 million. On June 18, 2010, the Company acquired Parklawn Business Park, a 232,000 square foot multi-tenant office and flex park located in Rockville, Maryland, for $23.4 million. On April 21, 2010, the Company acquired a portfolio of assets in Austin, Texas, aggregating 704,000 square feet of multi-tenant flex parks for $42.9 million. In connection with this purchase, the Company received a $129,000 credit for committed tenant improvements. On March 16, 2010, the Company acquired Shady Grove Executive Center, a 350,000 square foot multi-tenant office park located in Rockville, Maryland, for $60.0 million. In connection with this purchase, the Company received a $1.6 million credit for committed tenant improvements and lease commissions. The Company incurred and expensed acquisition transaction costs of $3.3 million for the year ended December 31, 2010.

The following table summarizes the assets acquired and liabilities assumed during the years ended December 31, (in thousands):

		2012			2011			2010
Land	$	20,779		$	210,255		$	71,142
Buildings and improvements		30,621			344,760			223,428
Above-market in-place lease value		709			2,915			6,304
Below-market in-place lease value		(251	)		(4,768	)		(2,348	)
Total purchase price		51,858			553,162			298,526
Mortgage note assumed		—			(250,000	)		—
Net operating assets acquired and liabilities assumed		(836	)		(5,424	)		(2,275	)
Total cash paid	$	51,022		$	297,738		$	296,251

     The purchase price of acquired properties is recorded to land, buildings and improvements and intangible assets and liabilities associated with in-place leases (including tenant improvements, unamortized lease commissions, value of above-market and below-market leases, acquired in-place lease values, and tenant relationships, if any) based on their respective estimated fair values. Acquisition related costs are expensed as incurred.

     In determining the fair value of the tangible assets of the acquired properties, management considers the value of the properties as if vacant as of the acquisition date. Management must make significant assumptions in determining the value of assets acquired and liabilities assumed. Using different assumptions in the recording of the purchase cost of the acquired properties would affect the timing of recognition of the related revenue and expenses. Amounts recorded to land are derived from comparable sales of land within the same region. Amounts recorded to buildings and improvements, tenant improvements and unamortized lease commissions are based on current market replacement costs and other market information. The amount recorded to acquired in-place leases is determined based on management's assessment of current market conditions and the estimated lease-up periods for the respective spaces.

     In 2010, the Company completed construction on a parcel of land within the Miami International Commerce Center in Miami, Florida, which added 75,000 square feet of rentable small tenant industrial space.

     In October, 2012, the Company completed the sale of Quail Valley Business Park, a 66,000 square foot flex park in Houston, Texas, for a gross sales price of $2.3 million, resulting in a net gain of $935,000.

     In August, 2011, the Company completed the sale of Westchase Corporate Park, a 177,000 square foot flex park consisting of 13 buildings in Houston, Texas, for a gross sales price of $9.8 million, resulting in a net gain of $2.7 million.

     In January, 2010, the Company completed the sale of a 131,000 square foot office building located in Houston, Texas, for a gross sales price of $10.0 million, resulting in a net gain of $5.2 million.

     The following table summarizes the condensed results of operations of the properties sold during 2012, 2011 and 2010 (in thousands):

		For the Years Ended December 31,
		2012			2011			2010
Rental income	$	281		$	1,459		$	2,232
Cost of operations		(143	)		(808	)		(1,243	)
Depreciation		(96	)		(291	)		(514	)
Income from discontinued operations	$	42		$	360		$	475

     In addition to minimum rental payments, tenants reimburse the Company for their pro rata share of specified operating expenses, which amounted to $617,000 and $852,000 for the years ended December 31, 2011 and 2010, respectively. No such amounts were recorded for the year ended December 31, 2012. These amounts are included as rental income in the table presented above.

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Mortgage Notes Payable (Mortgage Notes Payable Maturity Period) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Mortgage Notes Payable [Abstract]
Mortgage notes payable, weighted average interest rate	5.46%
Mortgage notes payable, weighted average maturity (in years)	3 years 8 months 12 days
2013	$ 18,102
2014
2015
2016	250,000
Total	$ 268,102	$ 282,084

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Supplementary Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2012

Supplementary Quarterly Financial Data [Abstract]

Schedule Of Supplemental Quarterly Financial Data

				Three Months Ended
		March 31,		June 30,	September 30,		December 31,
		2012		2012		2012		2012
				(In thousands, except per share data)
Revenues	$	84,677	$	85,627	$	87,020	$	89,224
Cost of operations	$	28,115	$	27,717	$	29,294	$	28,982
Net income allocable to common
shareholders	$	3,467	$	1,410	$	5,172	$	9,760
Net income per share:
Basic	$	0.14	$	0.06	$	0.21	$	0.40
Diluted	$	0.14	$	0.06	$	0.21	$	0.40

				Three Months Ended
		March 31,		June 30,	September 30,		December 31,
		2011		2011		2011		2011
				(In thousands, except per share data)
Revenues	$	73,461	$	72,970	$	76,463	$	74,563
Cost of operations	$	25,655	$	24,156	$	24,778	$	25,328
Net income allocable to common
shareholders	$	16,562	$	11,374	$	15,444	$	8,801
Net income per share:
Basic	$	0.67	$	0.46	$	0.63	$	0.36
Diluted	$	0.67	$	0.46	$	0.63	$	0.36

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Stock Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

Summary Of Stock Options Activity

					Weighted		Aggregate
				Weighted	Average		Intrinsic
	Number of			Average	Remaining		Value
Options:	Options			Exercise Price	Contract Life		(in thousands)
Outstanding at December 31, 2009	542,752		$	39.43
Granted	291,000		$	52.79
Exercised	(243,936	)	$	31.90
Forfeited	(12,000	)	$	58.19
Outstanding at December 31, 2010	577,816		$	48.95
Granted	14,000		$	60.66
Exercised	(24,600	)	$	42.67
Forfeited	—		$	—
Outstanding at December 31, 2011	567,216		$	49.51
Granted	44,000		$	66.69
Exercised	(143,043	)	$	41.30
Forfeited	(13,600	)	$	61.05
Outstanding at December 31, 2012	454,573		$	53.41	6.07 Years	$	5,436
Exercisable at December 31, 2012	229,173		$	51.70	4.54 Years	$	3,146

Nonvested Restricted Stock Units

				Weighted
	Number of			Average Grant
Restricted Stock Units:	Units			Date Fair Value
Nonvested at December 31, 2009	119,091		$	53.64
Granted	13,900		$	54.44
Vested	(44,857	)	$	53.84
Forfeited	(2,460	)	$	55.90
Nonvested at December 31, 2010	85,674		$	53.60
Granted	8,700		$	51.63
Vested	(29,890	)	$	55.88
Forfeited	(5,260	)	$	52.70
Nonvested at December 31, 2011	59,224		$	52.24
Granted	17,800		$	65.14
Vested	(20,094	)	$	51.36
Forfeited	(3,840	)	$	53.95
Nonvested at December 31, 2012	53,090		$	55.69

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Noncontrolling Interests (Narrative) (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 28, 2011 Series J&Q [Member]	Dec. 31, 2012 Series J&Q [Member]	Dec. 31, 2011 Series J&Q [Member]	Feb. 28, 2011 Series J [Member]	Dec. 31, 2011 Series J [Member]	Jun. 08, 2012 Series N [Member]	Dec. 31, 2012 Series N [Member]	Feb. 28, 2011 Series Q [Member]	Dec. 31, 2011 Series Q [Member]	May 12, 2010 Series G [Member]	Dec. 31, 2012 Series G [Member]	Dec. 31, 2010 Series G [Member]
Common units owned by affiliate	7,305,355
Percentage of common shares outstanding, if common units owned by affiliate were converted	23.10%
Affiliate's percent ownership of the Company's common equity	41.50%
Redemption/Repurchase date of preferred equity					Feb. 01, 2011					Jun. 08, 2012				May 12, 2010
Units redeemed or repurchased							1,710,000		223,300		203,400		800,000
Cumulative preferred stock, dividend rate								7.50%		7.125%		6.55%			7.95%
Amount paid to repurchase Preferred Units				$ 39,100,000					$ 5,600,000				$ 20,000,000
Issuance costs related to the redemption of preferred units	149,000		582,000			1,400,000									582,000
Weighted average purchase price				$ 20.43
Aggregate par value of preferred units repurchased						47,800,000
Gain on repurchase of preferred units net of issuance costs		$ 7,389,000

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Organization And Description Of Business (Details)	Dec. 31, 2012 state sqft
Organization And Description Of Business [Abstract]
The Company's ownership percentage of the limited partnership	76.90%
Owned and operated properties (in rentable square feet)	28,300,000
Number of states with rentable commercial space	8
Managed properties (in rentable square feet)	1,200,000

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Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 segment	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Allowance for uncollectible accounts	$ 400,000	$ 400,000
Cash and cash equivalents maximum benchmark (in months)	3 months
Minimum expenditure costs subject to capitalization and depreciation	2,000
Minimum expected future benefit period on expenditures cost to be capitalized and depreciated (in years)	2 years
Minimum transaction cost subject to capitalization and depreciation	1,000
Minimum expected future benefit period on transaction cost to be capitalized and depreciated (in years)	1 year
Maximum transaction costs subject to being expensed as incurred	1,000
Maximum length of lease period for transaction costs to be expensed as incurred	1 year
Net amortization of intangible assets and liabilities resulting from above-market and below-market lease	501,000	843,000	571,000
Value of in-place leases resulting in a net intangible asset	5,200,000	6,900,000
Accumulated amortization - intangible assets	4,700,000	2,300,000
Intangible assets, weighted average amortization period (in years)	6 years 4 months 24 days
Value of in-place leases resulting in a net intangible liability	4,700,000	6,400,000
Accumulated amortization - intangible liabilities	$ 3,000,000	$ 1,100,000
Intangible liability, weighted average amortization period (in years)	5 years
Distribution of taxable income requirement	90.00%
Odds of a particular tax position will be sustained upon examination or audit	50.00%
Anti-dilutive share options to purchase	51,200	92,000	78,000
Number of operating segments	1
Maximum [Member] | Building And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	30 years
Minimum [Member] | Building And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	5 years

XML

Summary Of Significant Accounting Policies

12 Months Ended

Dec. 31, 2012

Summary Of Significant Accounting Policies [Abstract]

Summary Of Significant Accounting Policies

2. Summary of significant accounting policies

Basis of presentation

     The accompanying consolidated financial statements include the accounts of PSB and the Operating Partnership. All significant inter-company balances and transactions have been eliminated in the consolidated financial statements.

Noncontrolling Interests

     The Company's noncontrolling interests are reported as a component of equity separate from the parent's equity. Purchases or sales of equity interests that do not result in a change in control are accounted for as equity transactions. In addition, net income attributable to the noncontrolling interest is included in consolidated net income on the face of the income statement and, upon a gain or loss of control, the interest purchased or sold, as well as any interest retained, is recorded at fair value with any gain or loss recognized in earnings.

Use of estimates

     The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates.

Allowance for doubtful accounts

     The Company monitors the collectability of its receivable balances including the deferred rent receivable on an ongoing basis. Based on these reviews, the Company maintains an allowance for doubtful accounts for estimated losses resulting from the possible inability of tenants to make contractual rent payments to the Company. A provision for doubtful accounts is recorded during each period. The allowance for doubtful accounts, which represents the cumulative allowances less write-offs of uncollectible rent, is netted against tenant and other receivables on the consolidated balance sheets. Tenant receivables are net of an allowance for uncollectible accounts totaling $400,000 at December 31, 2012 and 2011.

Financial instruments

     The methods and assumptions used to estimate the fair value of financial instruments are described below. The Company has estimated the fair value of financial instruments using available market information and appropriate valuation methodologies. Considerable judgment is required in interpreting market data to develop estimates of market value. Accordingly, estimated fair values are not necessarily indicative of the amounts that could be realized in current market exchanges. The Company determines the estimated fair value of financial assets and liabilities utilizing a hierarchy of valuation techniques based on whether the inputs to a fair value measurement are considered to be observable or unobservable in a marketplace. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions. This hierarchy requires the use of observable market data when available. The following is the fair value hierarchy:

· Level 1—quoted prices for identical instruments in active markets

· Level 2—quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which significant inputs and significant value drivers are observable in active markets; and· Level 3—fair value measurements derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable

     Financial assets that are exposed to credit risk consist primarily of cash and cash equivalents and receivables. The Company considers all highly liquid investments with a remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents, which consist primarily of money market investments, are only invested in entities with an investment grade rating. Receivables are comprised of balances due from a large number of customers. Balances that the Company expects to become uncollectible are reserved for or written off. Due to the short period to maturity of the Company's cash and cash equivalents, accounts receivable, other assets and accrued and other liabilities, the carrying values as presented on the consolidated balance sheets are reasonable estimates of fair value.

     Carrying values of the Company's mortgage notes payable, unsecured credit facility and term loan are deemed to approximate fair value. The characteristics of these financial instruments, market data and other comparative metrics utilized in determining these fair values are "Level 2" inputs.

Real estate facilities

     Real estate facilities are recorded at cost. Costs related to the renovation or improvement of the properties are capitalized. Expenditures for repairs and maintenance are expensed as incurred. Expenditures that are expected to benefit a period greater than two years and exceed $2,000 are capitalized and depreciated over their estimated useful life. Buildings and improvements are depreciated using the straight-line method over their estimated useful lives, which generally range from five to 30 years. Transaction costs, which include tenant improvements and lease commissions, in excess of $1,000 for leases with terms greater than one year are capitalized and depreciated over their estimated useful lives. Transaction costs less than $1,000 or leases of one year or less are expensed as incurred.

Properties held for disposition

     An asset is classified as an asset held for disposition when it meets certain requirements, which include, among other criteria, the approval of the sale of the asset, the marketing of the asset for sale and the expectation by the Company that the sale will likely occur within the next 12 months. Upon classification of an asset as held for disposition, depreciation of the asset is ceased, the operating results of the asset are included in discontinued operations for all periods presented and the net book value of the asset is included on the balance sheet as properties held for disposition.

Intangible assets/liabilities

     Intangible assets and liabilities include above-market and below-market in-place lease values of acquired properties based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) management's estimate of fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. The capitalized above-market and below-market lease values (included in other assets and accrued liabilities in the accompanying consolidated balance sheets) are amortized to rental income over the remaining non-cancelable terms of the respective leases. The Company recorded net amortization reducing rental income of $501,000, $843,000 and $571,000 of intangible assets and liabilities resulting from the above-market and below-market lease values during the years ended December 31, 2012, 2011 and 2010, respectively. As of December 31, 2012, the value of in-place leases resulted in a net intangible asset of $5.2 million, net of $4.7 million of accumulated amortization with a weighted average amortization period of 6.4 years, and a net intangible liability of $4.7 million, net of $3.0 million of accumulated amortization with a weighted average amortization period of 5.0 years. As of December 31, 2011, the value of in-place leases resulted in a net intangible asset of $6.9 million, net of $2.3 million of accumulated amortization and a net intangible liability of $6.4 million, net of $1.1 million of accumulated amortization.

Evaluation of asset impairment

     The Company evaluates its assets used in operations for impairment by identifying indicators of impairment and by comparing the sum of the estimated undiscounted future cash flows for each asset to the asset's carrying value. When indicators of impairment are present and the sum of the estimated undiscounted future cash flows is less than the carrying value of such asset, an impairment loss is recorded equal to the difference between the asset's current carrying value and its value based on discounting its estimated future cash flows. In addition, the Company evaluates its assets held for disposition for impairment. Assets held for disposition are reported at the lower of their carrying value or fair value, less cost of disposition. At December 31, 2012, the Company did not consider any assets to be impaired.

Asset impairment due to casualty loss

     It is the Company's policy to record as a casualty loss or gain, in the period the casualty occurs, the differential between (a) the book value of assets destroyed and (b) any insurance proceeds that the Company expects to receive in accordance with its insurance contracts. Potential proceeds from insurance that are subject to any uncertainties, such as interpretation of deductible provisions of the governing agreements, the estimation of costs of restoration, or other such items, are treated as contingent proceeds and not recorded until the uncertainties are satisfied.

For the years ended December 31, 2012, 2011 and 2010 no material casualty losses were incurred.

Stock compensation

     All share-based payments to employees, including grants of employee stock options, are recognized as stock compensation in the Company's income statement based on their grant date fair values. See Note 10.

Revenue and expense recognition

     The Company must meet four basic criteria before revenue can be recognized: persuasive evidence of an arrangement exists; the delivery has occurred or services rendered; the fee is fixed or determinable; and collectability is reasonably assured. All leases are classified as operating leases. Rental income is recognized on a straight-line basis over the terms of the leases. Straight-line rent is recognized for all tenants with contractual fixed increases in rent that are not included on the Company's credit watch list. Deferred rent receivable represents rental revenue recognized on a straight-line basis in excess of billed rents. Reimbursements from tenants for real estate taxes and other recoverable operating expenses are recognized as rental income in the period the applicable costs are incurred. Property management fees are recognized in the period earned.

     Costs incurred in connection with leasing (primarily tenant improvements and lease commissions) are capitalized and amortized over the lease period.

Gains from sales of real estate facilities

     The Company recognizes gains from sales of real estate facilities at the time of sale using the full accrual method, provided that various criteria related to the terms of the transactions and any subsequent involvement by the Company with the properties sold are met. If the criteria are not met, the Company defers the gains and recognizes them when the criteria are met or uses the installment or cost recovery methods as appropriate under the circumstances.

General and administrative expenses

     General and administrative expenses include executive and other compensation, office expense, professional fees, acquisition transaction costs, state income taxes and other such administrative items.

Income taxes

     The Company has qualified and intends to continue to qualify as a REIT, as defined in Section 856 of the Internal Revenue Code. As a REIT, the Company is not subject to federal income tax to the extent that it distributes its REIT taxable income to its shareholders. A REIT must distribute at least 90% of its taxable income each year. In addition, REITs are subject to a number of organizational and operating requirements. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to federal income tax (including any applicable alternative minimum tax) based on its taxable income using corporate income tax rates. Even if the Company qualifies for taxation as a REIT, the Company may be subject to certain state and local taxes on its income and property and to federal income and excise taxes on its undistributed taxable income. The Company believes it met all organization and operating requirements to maintain its REIT status during 2012, 2011 and 2010 and intends to continue to meet such requirements. Accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements.

     The Company can recognize a tax benefit only if it is "more likely than not" that a particular tax position will be sustained upon examination or audit. To the extent that the "more likely than not" standard has been satisfied, the benefit associated with a position is measured as the largest amount that is greater than 50% likely of being recognized upon settlement. As of December 31, 2012, the Company did not recognize any tax benefit for uncertain tax positions.

Accounting for preferred equity issuance costs

     The Company records issuance costs as a reduction to paid-in capital on its balance sheet at the time the preferred securities are issued and reflects the carrying value of the preferred equity at the stated value. The Company records issuance costs as non-cash preferred equity distributions at the time it notifies the holders of preferred stock or units of its intent to redeem such shares or units.

Net income allocation

Net income was allocated as follows for the years ended December 31, (in thousands):

		2012		2011			2010
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units:
Continuing operations	$	5,744	$	14,838		$	10,307
Discontinued operations		226		705			1,287
Total net income allocable to noncontrolling interests —
common units		5,970		15,543			11,594
Noncontrolling interests — preferred units:
Distributions to preferred unit holders		174		398			4,521
Issuance costs related to the redemption of preferred units		149		—			582
Gain on repurchase of preferred units, net of issuance costs		—		(7,389	)		—
Total net income allocable to noncontrolling interests —
preferred units		323		(6,991	)		5,103
Total net income allocable to noncontrolling interests		6,293		8,552			16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders:
Distributions to preferred shareholders		51,969		41,799			42,730
Issuance costs related to the redemption of preferred stock		17,167		—			3,484
Total net income allocable to preferred shareholders		69,136		41,799			46,214
Restricted stock unit holders:
Continuing operations		135		121			135
Discontinued operations		3		6			17
Total net income allocable to restricted stock unit holders		138		127			152
Common shareholders:
Continuing operations		19,057		49,796			34,635
Discontinued operations		748		2,366			4,324
Total net income allocable to common shareholders		19,805		52,162			38,959
Total net income allocable to PS Business Parks, Inc		89,079		94,088			85,325
Net income	$	95,372	$	102,640		$	102,022

Net income per common share

     Per share amounts are computed using the number of weighted average common shares outstanding. "Diluted" weighted average common shares outstanding includes the dilutive effect of stock options and restricted stock units under the treasury stock method. "Basic" weighted average common shares outstanding excludes such effect. The Company's restricted stock units are participating securities and are included in the computation of basic and diluted weighted average common shares outstanding. The Company's restricted stock unit holders are paid non-forfeitable dividends in excess of the expense recorded which results in a reduction in net income allocable to common shareholders and unit holders. Earnings per share has been calculated as follows for the years ended December 31, (in thousands, except per share amounts):

		2012		2011		2010
Net income allocable to common shareholders	$	19,805	$	52,162	$	38,959
Weighted average common shares outstanding:
Basic weighted average common shares outstanding		24,234		24,516		24,546
Net effect of dilutive stock compensation — based on
treasury stock method using average market price		89		83		141
Diluted weighted average common shares outstanding		24,323		24,599		24,687
Net income per common share — Basic	$	0.82	$	2.13	$	1.59
Net income per common share — Diluted	$	0.81	$	2.12	$	1.58

     Options to purchase 51,200, 92,000 and 78,000 shares for the years ended December 31 2012, 2011 and 2010, respectively, were not included in the computation of diluted net income per share because such options were considered anti-dilutive.

Segment reporting

The Company views its operations as one segment.

Reclassifications

     Certain reclassifications have been made to the consolidated financial statements for 2011 and 2010 in order to conform to the 2012 presentation.

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Summary Of Significant Accounting Policies (Net Income Allocation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary Of Significant Accounting Policies [Abstract]
Noncontrolling interests - common units: Continuing operations									$ 5,744	$ 14,838	$ 10,307
Noncontrolling interests - common units: Discontinued operations									226	705	1,287
Total net income allocable to noncontrolling interests - common units									5,970	15,543	11,594
Noncontrolling interests - preferred units: Distributions to preferred unit holders									174	398	4,521
Noncontrolling interests - preferred units: Issuance costs related to the redemption of preferred units									149		582
Noncontrolling interests - preferred units: Gain on repurchase of preferred units, net of issuance costs										(7,389)
Total net income allocable to noncontrolling interests - preferred units									323	(6,991)	5,103
Total net income allocable to noncontrolling interests									6,293	8,552	16,697
Preferred shareholders: Distributions to preferred shareholders									51,969	41,799	42,730
Preferred shareholders: Issuance costs related to the redemption of preferred stock									17,167		3,484
Total net income allocable to preferred shareholders									69,136	41,799	46,214
Restricted stock unit holders: Continuing operations									135	121	135
Restricted stock unit holders: Discontinued operations									3	6	17
Total net income allocable to restricted stock unit holders									138	127	152
Common shareholders: Continuing operations									19,057	49,796	34,635
Common shareholders: Discontinued operations									748	2,366	4,324
Total net income allocable to common shareholders	9,760	5,172	1,410	3,467	8,801	15,444	11,374	16,562	19,805	52,162	38,959
Total net income allocable to PS Business Parks, Inc									89,079	94,088	85,325
Net income									$ 95,372	$ 102,640	$ 102,022

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Leasing Activity (Summary Of Future Minimum Rental Revenues Excluding Recovery Of Operating Expenses) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Leasing Activity [Abstract]
2013	$ 244,595
2014	179,923
2015	124,246
2016	84,954
2017	55,384
Thereafter	92,496
Total	$ 781,598

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Supplementary Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplementary Quarterly Financial Data [Abstract]
Revenues	$ 89,224	$ 87,020	$ 85,627	$ 84,677	$ 74,563	$ 76,463	$ 72,970	$ 73,461	$ 346,548	$ 297,457	$ 276,276
Cost of operations	28,982	29,294	27,717	28,115	25,328	24,778	24,156	25,655	114,108	99,917	89,348
Net income allocable to common shareholders	$ 9,760	$ 5,172	$ 1,410	$ 3,467	$ 8,801	$ 15,444	$ 11,374	$ 16,562	$ 19,805	$ 52,162	$ 38,959
Net income per share: Basic	$ 0.40	$ 0.21	$ 0.06	$ 0.14	$ 0.36	$ 0.63	$ 0.46	$ 0.67	$ 0.82	$ 2.13	$ 1.59
Net income per share: Diluted	$ 0.40	$ 0.21	$ 0.06	$ 0.14	$ 0.36	$ 0.63	$ 0.46	$ 0.67	$ 0.81	$ 2.12	$ 1.58

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Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 12,883	$ 4,980
Real estate facilities, at cost:
Land	793,352	772,573
Buildings and improvements	2,235,448	2,155,772
Gross real estate investment property	3,028,800	2,928,345
Accumulated depreciation	(942,639)	(845,700)
Net real estate investment property	2,086,161	2,082,645
Properties held for disposition, net		1,218
Land held for development	6,829	6,829
Total real estate investments	2,092,990	2,090,692
Rent receivable	4,754	3,198
Deferred rent receivable	25,329	23,388
Other assets	15,861	16,361
Total assets	2,151,817	2,138,619
LIABILITIES AND EQUITY
Accrued and other liabilities	69,454	60,940
Credit facility		185,000
Term loan	200,000	250,000
Mortgage notes payable	268,102	282,084
Total liabilities	537,556	778,024
Commitments and contingencies
PS Business Parks, Inc.'s shareholders' equity:
Preferred stock, $0.01 par value, 50,000,000 shares authorized, 35,400 and 23,942 shares issued and outstanding at December 31, 2012 and 2011, respectively	885,000	598,546
Common stock, $0.01 par value, 100,000,000 shares authorized, 24,298,475 and 24,128,184 shares issued and outstanding at December 31, 2012 and 2011, respectively	242	240
Paid-in capital	537,091	534,322
Cumulative net income	967,783	878,704
Cumulative distributions	(944,427)	(832,607)
Total PS Business Parks, Inc.'s shareholders' equity	1,445,689	1,179,205
Noncontrolling interests:
Preferred units		5,583
Common units	168,572	175,807
Total noncontrolling interests	168,572	181,390
Total equity	1,614,261	1,360,595
Total liabilities and equity	$ 2,151,817	$ 2,138,619

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Noncontrolling Interests (Operating Partnership Of Preferred Units Outstanding) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Units Outstanding		223,300
Amount		$ 5,583
Series N [Member]
Issuance Date	December, 2005
Earliest Potential Redemption Date	Dec. 01, 2010
Dividend Rate	7.125%
Units Outstanding		223,300
Amount		$ 5,583

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Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 95,372	$ 102,640	$ 102,022
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	109,494	84,682	78,868
In-place lease adjustment	501	843	571
Tenant improvement reimbursements net of lease incentives	(1,315)	(769)	(603)
Amortization of mortgage premium		(215)	(285)
Gain on sale of real estate facilities	(935)	(2,717)	(5,153)
Stock compensation	5,434	1,965	2,116
Increase in receivables and other assets	(5,025)	(3,074)	(2,809)
Increase (decrease) in accrued and other liabilities	5,601	(2,735)	2,389
Total adjustments	113,755	77,980	75,094
Net cash provided by operating activities	209,127	180,620	177,116
Cash flows from investing activities:
Capital improvements to real estate facilities	(56,772)	(48,367)	(39,553)
Acquisition of real estate facilities	(51,022)	(297,738)	(296,251)
Proceeds from the sale of real estate facility	2,065	8,999	9,181
Net cash used in investing activities	(105,729)	(337,106)	(326,623)
Cash flows from financing activities:
Borrowings on credit facility	154,000	185,000	93,000
Borrowings on term loan		250,000
Note payable to affiliate		121,000
Repayment of borrowings on credit facility	(339,000)	(93,000)
Repayment of borrowings on term loan debt	(50,000)
Repayment of borrowings on note payable to affiliate		(121,000)
Principal payments on mortgage notes payable	(828)	(1,032)	(1,091)
Repayment of mortgage note payable	(13,154)	(18,180)
Net proceeds from the issuance of preferred stock	784,392		72,513
Proceeds from the exercise of stock options	5,907	1,050	7,783
Redemption/repurchase of preferred stock	(523,546)		(102,500)
Redemption/repurchase of preferred units	(5,583)	(39,087)	(20,000)
Repurchase of common stock		(30,252)
Distributions paid to preferred shareholders	(51,969)	(41,799)	(42,730)
Distributions paid to noncontrolling interests - common units	(12,856)	(12,856)	(12,856)
Distributions paid to noncontrolling interests - preferred units	(174)	(398)	(4,521)
Distributions paid to common shareholders	(42,684)	(43,046)	(43,254)
Net cash (used in) provided by financing activities	(95,495)	156,400	(53,656)
Net increase (decrease) in cash and cash equivalents	7,903	(86)	(203,163)
Cash and cash equivalents at the beginning of the period	4,980	5,066	208,229
Cash and cash equivalents at the end of the period	12,883	4,980	5,066
Supplemental disclosures:
Interest paid	18,872	5,041	3,547
Adjustment to noncontrolling interests in underlying operating partnership:
Noncontrolling interests - common units	(349)	5,689	901
Paid-in capital	349	(5,689)	(901)
Gain on repurchase of preferred equity:
Preferred units		(8,748)
Paid-in capital		8,748
Issuance costs related to the redemption/repurchase of preferred equity:
Cumulative distributions	(17,167)		(3,484)
Noncontrolling interest - common units	(149)	(1,359)	(582)
Paid-in capital	17,316	1,359	4,066
Mortgage note assumed in property acquisition:
Real estate facilities		(250,000)
Mortgage notes payable		$ 250,000

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Real Estate Facilities (Activity In Real Estate Facilities) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Balances	$ 2,082,645	$ 1,562,875	$ 1,306,509
Acquisition of real estate	51,400	555,015	294,570
Capital improvements, net	61,561	49,624	40,378
Depreciation expense	(109,494)	(84,682)	(78,868)
Transfer to properties held for disposition	49	(187)	286
Balances	2,086,161	2,082,645	1,562,875
Land [Member]
Property, Plant and Equipment [Line Items]
Balances	772,573	562,318	491,176
Acquisition of real estate	20,779	210,255	71,142
Balances	793,352	772,573	562,318
Building And Improvements [Member]
Property, Plant and Equipment [Line Items]
Balances	2,155,772	1,772,005	1,517,596
Acquisition of real estate	30,621	344,760	223,428
Capital improvements, net	61,561	49,624	40,378
Disposals	(12,459)	(10,150)	(9,237)
Transfer to properties held for disposition	(47)	(467)	(160)
Balances	2,235,448	2,155,772	1,772,005
Accumulated Depreciation [Member]
Property, Plant and Equipment [Line Items]
Balances	(845,700)	(771,448)	(702,263)
Disposals	12,459	10,150	9,237
Depreciation expense	(109,494)	(84,682)	(78,868)
Transfer to properties held for disposition	96	280	446
Balances	$ (942,639)	$ (845,700)	$ (771,448)

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Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Summary Of Significant Accounting Policies [Abstract]

Net Income Allocation

		2012		2011			2010
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units:
Continuing operations	$	5,744	$	14,838		$	10,307
Discontinued operations		226		705			1,287
Total net income allocable to noncontrolling interests —
common units		5,970		15,543			11,594
Noncontrolling interests — preferred units:
Distributions to preferred unit holders		174		398			4,521
Issuance costs related to the redemption of preferred units		149		—			582
Gain on repurchase of preferred units, net of issuance costs		—		(7,389	)		—
Total net income allocable to noncontrolling interests —
preferred units		323		(6,991	)		5,103
Total net income allocable to noncontrolling interests		6,293		8,552			16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders:
Distributions to preferred shareholders		51,969		41,799			42,730
Issuance costs related to the redemption of preferred stock		17,167		—			3,484
Total net income allocable to preferred shareholders		69,136		41,799			46,214
Restricted stock unit holders:
Continuing operations		135		121			135
Discontinued operations		3		6			17
Total net income allocable to restricted stock unit holders		138		127			152
Common shareholders:
Continuing operations		19,057		49,796			34,635
Discontinued operations		748		2,366			4,324
Total net income allocable to common shareholders		19,805		52,162			38,959
Total net income allocable to PS Business Parks, Inc		89,079		94,088			85,325
Net income	$	95,372	$	102,640		$	102,022

Calculation Of Earnings Per Share

		2012		2011		2010
Net income allocable to common shareholders	$	19,805	$	52,162	$	38,959
Weighted average common shares outstanding:
Basic weighted average common shares outstanding		24,234		24,516		24,546
Net effect of dilutive stock compensation — based on
treasury stock method using average market price		89		83		141
Diluted weighted average common shares outstanding		24,323		24,599		24,687
Net income per common share — Basic	$	0.82	$	2.13	$	1.59
Net income per common share — Diluted	$	0.81	$	2.12	$	1.58

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Real Estate Facilities (Summary Of Real Estate Assets Acquired And Liabilities Assumed) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Northern California Bay Area Portfolio [Member]	Dec. 20, 2011 Northern California Bay Area Portfolio [Member]
Land	$ 20,779	$ 210,255	$ 71,142	$ 202,131
Buildings and improvements	30,621	344,760	223,428	320,210
Above-market in-place lease value	709	2,915	6,304	2,372
Below-market in-place lease value	(251)	(4,768)	(2,348)	(4,713)
Total purchase price	51,858	553,162	298,526	520,000	520,000
Mortgage note assumed		(250,000)		(250,000)
Net operating assets acquired and liabilities assumed	(836)	(5,424)	(2,275)	5,171
Total cash paid	$ 51,022	$ 297,738	$ 296,251	$ 275,171

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Leasing Activity (Tables)

12 Months Ended

Dec. 31, 2012

Leasing Activity [Abstract]

Summary Of Future Minimum Rental Revenues Excluding Recovery Of Operating Expenses

2013	$	244,595
2014		179,923
2015		124,246
2016		84,954
2017		55,384
Thereafter		92,496
Total	$	781,598

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Organization And Description Of Business

12 Months Ended

Dec. 31, 2012

Organization And Description Of Business [Abstract]

Organization And Description Of Business

1. Organization and description of business

Organization

     PS Business Parks, Inc. ("PSB") was incorporated in the state of California in 1990. As of December 31, 2012, PSB owned 76.9% of the common partnership units of PS Business Parks, L.P. (the "Operating Partnership"). The remaining common partnership units are owned by Public Storage ("PS"). PSB, as the sole general partner of the Operating Partnership, has full, exclusive and complete responsibility and discretion in managing and controlling the Operating Partnership. PSB and the Operating Partnership are collectively referred to as the "Company."

Description of business

     The Company is a fully-integrated, self-advised and self-managed real estate investment trust ("REIT") that owns, operates, acquires and develops commercial properties, primarily multi-tenant flex, office and industrial space. As of December 31, 2012, the Company owned and operated 28.3 million rentable square feet of commercial space located in eight states. The Company also manages 1.2 million rentable square feet on behalf of PS.

     References to the number of properties or square footage are unaudited and outside the scope of the Company's independent registered public accounting firm's audit of the Company's financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States).

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Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	35,400	23,942
Preferred stock, shares outstanding	35,400	23,942
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	24,298,475	24,128,184
Common stock, shares outstanding	24,298,475	24,128,184

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Supplementary Quarterly Financial Data

12 Months Ended

Dec. 31, 2012

Supplementary Quarterly Financial Data [Abstract]

Supplementary Quarterly Financial Data

11. Supplementary quarterly financial data (unaudited)

				Three Months Ended
		March 31,		June 30,	September 30,		December 31,
		2012		2012		2012		2012
				(In thousands, except per share data)
Revenues	$	84,677	$	85,627	$	87,020	$	89,224
Cost of operations	$	28,115	$	27,717	$	29,294	$	28,982
Net income allocable to common
shareholders	$	3,467	$	1,410	$	5,172	$	9,760
Net income per share:
Basic	$	0.14	$	0.06	$	0.21	$	0.40
Diluted	$	0.14	$	0.06	$	0.21	$	0.40

				Three Months Ended
		March 31,		June 30,	September 30,		December 31,
		2011		2011		2011		2011
				(In thousands, except per share data)
Revenues	$	73,461	$	72,970	$	76,463	$	74,563
Cost of operations	$	25,655	$	24,156	$	24,778	$	25,328
Net income allocable to common
shareholders	$	16,562	$	11,374	$	15,444	$	8,801
Net income per share:
Basic	$	0.67	$	0.46	$	0.63	$	0.36
Diluted	$	0.67	$	0.46	$	0.63	$	0.36

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Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Feb. 18, 2013	Jun. 30, 2012
Document And Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Registrant Name	PS BUSINESS PARKS INC/CA
Entity Central Index Key	0000866368
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		24,298,475
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 1,229,654,681

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Commitments And Contingencies

12 Months Ended

Dec. 31, 2012

Commitments And Contingencies [Abstract]

Commitments And Contingencies

12. Commitments and contingencies

     Substantially all of the Company's properties have been subjected to Phase I environmental reviews. Such reviews have not revealed, nor is management aware of, any probable or reasonably possible environmental costs that management believes would have a material adverse effect on the Company's business, assets or results of operations, nor is the Company aware of any potentially material environmental liability.

     Other than routine litigation and administrative proceedings arising in the ordinary course of business, the Company currently is neither subject to any other material litigation nor, to management's knowledge, is any material litigation currently threatened against the Company.

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Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Rental income	$ 346,548	$ 297,457	$ 276,276
Facility management fees	649	684	672
Total operating revenues	347,197	298,141	276,948
Expenses:
Cost of operations	114,108	99,917	89,348
Depreciation and amortization	109,398	84,391	78,354
General and administrative	8,919	9,036	9,651
Total operating expenses	232,425	193,344	177,353
Other income and (expenses):
Interest and other income	241	221	333
Interest expense	(20,618)	(5,455)	(3,534)
Total other income and (expenses)	(20,377)	(5,234)	(3,201)
Income from continuing operations	94,395	99,563	96,394
Discontinued operations:
Income from discontinued operations	42	360	475
Gain on sale of real estate facility	935	2,717	5,153
Total discontinued operations	977	3,077	5,628
Net income	95,372	102,640	102,022
Net income allocable to noncontrolling interests:
Noncontrolling interests - common units	5,970	15,543	11,594
Noncontrolling interests - preferred units	323	(6,991)	5,103
Total net income allocable to noncontrolling interests	6,293	8,552	16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders	69,136	41,799	46,214
Restricted stock unit holders	138	127	152
Common shareholders	19,805	52,162	38,959
Total net income allocable to PS Business Parks, Inc	89,079	94,088	85,325
Net income	$ 95,372	$ 102,640	$ 102,022
Net income per common share - basic:
Continuing operations	$ 0.79	$ 2.03	$ 1.41
Discontinued operations	$ 0.03	$ 0.10	$ 0.18
Net income	$ 0.82	$ 2.13	$ 1.59
Net income per common share - diluted:
Continuing operations	$ 0.78	$ 2.02	$ 1.40
Discontinued operations	$ 0.03	$ 0.10	$ 0.18
Net income	$ 0.81	$ 2.12	$ 1.58
Weighted average common shares outstanding:
Basic	24,234	24,516	24,546
Diluted	24,323	24,599	24,687

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Mortgage Notes Payable

12 Months Ended

Dec. 31, 2012

Mortgage Notes Payable [Abstract]

Mortgage Notes Payable

6. Mortgage notes payable

Mortgage notes payable consist of the following (in thousands):

		December 31,		December 31,
		2012		2011
5.45% mortgage note, secured by 4.8 million square feet of
commercial properties with a net book value of $448.4 million,
interest payable monthly, due December, 2016	$	250,000	$	250,000
5.52% mortgage note, secured by one commercial property with a
net book value of $14.7 million, principal and interest payable
monthly, repaid January, 2013		9,036		9,311
5.68% mortgage note, secured by one commercial property with a
net book value of $16.4 million, principal and interest payable
monthly, repaid January, 2013		9,066		9,337
5.73% mortgage note, repaid November, 2012		—		13,436
Total	$	268,102	$	282,084

     At December 31, 2012, mortgage notes payable had a weighted average interest rate of 5.46% and a weighted average maturity of 3.7 years with principal payments as follows (in thousands):

2013	$	18,102
2014		—
2015		—
2016		250,000
Total	$	268,102

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Bank Loans

12 Months Ended

Dec. 31, 2012

Bank Loans [Abstract]

Bank Loans

5. Bank loans

     The Company has a line of credit (the "Credit Facility") with Wells Fargo Bank, National Association ("Wells Fargo") which expires on August 1, 2015. The Credit Facility has a borrowing limit of $250.0 million. The rate of interest charged on borrowings is equal to a rate ranging from the London Interbank Offered Rate ("LIBOR") plus 1.00% to LIBOR plus 1.85% depending on the Company's credit ratings. Currently, the Company's rate under the Credit Facility is LIBOR plus 1.10%. In addition, the Company is required to pay an annual facility fee ranging from 0.15% to 0.45% of the borrowing limit depending on the Company's credit ratings (currently 0.15%). The Company had no balance outstanding on the Credit Facility at December 31, 2012. The Company had $185.0 million outstanding on the Credit Facility at an interest rate of 1.41% at December 31, 2011. The Company had $791,000 and $1.1 million of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The Credit Facility requires the Company to meet certain covenants, with which the Company was in compliance at December 31, 2012 and 2011. Interest on outstanding borrowings is payable monthly.

     In connection with the Northern California Portfolio acquisition described in Note 3, the Company entered into a term loan on December 20, 2011 with Wells Fargo, as Administrative Agent (the "Term Loan"). Pursuant to the Term Loan, the Company borrowed $250.0 million for a three year term through December 31, 2014. The maturity date of the Term Loan Agreement can be extended by one year at the Company's election. Interest on the amounts borrowed under the Term Loan accrues based on an applicable rate ranging from LIBOR plus 1.15% to LIBOR plus 2.25% depending on the Company's credit ratings. Currently, the Company's rate under the Term Loan is LIBOR plus 1.20%. The Company had $200.0 million outstanding on the Term Loan at an interest rate of 1.41% at December 31, 2012 and $250.0 million outstanding at an interest rate of 1.50% at December 31, 2011. The Company had $383,000 and $729,000 of unamortized commitment fees as of December 31, 2012 and 2011, respectively. The covenants and events of default contained in the Credit Facility are incorporated into the Term Loan by reference, and the Term Loan is cross-defaulted to the Credit Facility. The Term Loan can be repaid in full or part at any time prior to its maturity without penalty.

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Real Estate Facilities (Tables)

12 Months Ended

Dec. 31, 2012

Real Estate Properties [Line Items]

Activity In Real Estate Facilities

				Buildings and			Accumulated
		Land		Equipment			Depreciation			Total
Balances at December 31, 2009	$	491,176	$	1,517,596		$	(702,263	)	$	1,306,509
Acquisition of real estate facilities		71,142		223,428			—			294,570
Capital improvements, net		—		40,378			—			40,378
Disposals		—		(9,237	)		9,237			—
Depreciation expense		—		—			(78,868	)		(78,868	)
Transfer to properties held for
disposition		—		(160	)		446			286
Balances at December 31, 2010		562,318		1,772,005			(771,448	)		1,562,875
Acquisition of real estate facilities		210,255		344,760			—			555,015
Capital improvements, net		—		49,624			—			49,624
Disposals		—		(10,150	)		10,150			—
Depreciation expense		—		—			(84,682	)		(84,682	)
Transfer to properties held for
disposition		—		(467	)		280			(187	)
Balances at December 31, 2011		772,573		2,155,772			(845,700	)		2,082,645
Acquisition of real estate facilities		20,779		30,621			—			51,400
Capital improvements, net		—		61,561			—			61,561
Disposals		—		(12,459	)		12,459			—
Depreciation expense		—		—			(109,494	)		(109,494	)
Transfer to properties held for
disposition		—		(47	)		96			49
Balances at December 31, 2012	$	793,352	$	2,235,448		$	(942,639	)	$	2,086,161

Summary Of Real Estate Assets Acquired And Liabilities Assumed

		2012			2011			2010
Land	$	20,779		$	210,255		$	71,142
Buildings and improvements		30,621			344,760			223,428
Above-market in-place lease value		709			2,915			6,304
Below-market in-place lease value		(251	)		(4,768	)		(2,348	)
Total purchase price		51,858			553,162			298,526
Mortgage note assumed		—			(250,000	)		—
Net operating assets acquired and liabilities assumed		(836	)		(5,424	)		(2,275	)
Total cash paid	$	51,022		$	297,738		$	296,251

Summary Of Unaudited Pro Forma Portfolio Acquisition

		For The Years Ended
		December 31,
		2011		2010
Pro Forma Revenues	$	336,680	$	317,770
Pro Forma Net income	$	95,595	$	91,088
Pro Forma Net income per common share:
Basic	$	1.91	$	1.24
Diluted	$	1.90	$	1.24

Condensed Results Of Operations For The Properties Sold

		For the Years Ended December 31,
		2012			2011			2010
Rental income	$	281		$	1,459		$	2,232
Cost of operations		(143	)		(808	)		(1,243	)
Depreciation		(96	)		(291	)		(514	)
Income from discontinued operations	$	42		$	360		$	475

Northern California Bay Area Portfolio [Member]

Real Estate Properties [Line Items]

Summary Of Real Estate Assets Acquired And Liabilities Assumed

Land	$	202,131
Buildings and improvements		320,210
Above-market in-place lease value		2,372
Below-market in-place lease value		(4,713	)
Total purchase price		520,000
Mortgage note assumed		(250,000	)
Net operating assets acquired and liabilities assumed		5,171
Total cash paid	$	275,171

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401(K) Plan

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

401(K) Plan

13. 401(K) Plan

     The Company has a 401(K) savings plan (the "Plan") in which all eligible employees may participate. The Plan provides for the Company to make matching contributions to all eligible employees up to 4% of their annual salary dependent on the employee's level of participation. For the years ended December 31, 2012, 2011 and 2010, $345,000, $328,000 and $297,000, respectively, was charged as expense related to this plan.

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Shareholders' Equity

12 Months Ended

Dec. 31, 2012

Shareholders' Equity [Abstract]

Shareholders' Equity

9. Shareholders' equity

Preferred stock

As of December 31, 2012 and 2011, the Company had the following series of preferred stock outstanding:

					December 31, 2012			December 31, 2011
		Earliest Potential Dividend			Shares		Amount	Shares		Amount
Series	Issuance Date	Redemption Date	Rate		Outstanding	(in thousands) Outstanding			(in thousands)
Series R	October, 2010	October, 2015	6.875	%	3,000	$	75,000	3,000	$	75,000
Series S	January, 2012	January, 2017	6.450	%	9,200		230,000	—		—
Series T	May, 2012	May, 2017	6.000	%	14,000		350,000	—		—
Series U	September, 2012	September, 2017	5.750	%	9,200		230,000	—		—
Series H	January & October, 2004	January, 2009	7.000	%	—		—	6,341		158,520
Series I	April, 2004	April, 2009	6.875	%	—		—	2,745		68,626
Series M	May, 2005	May, 2010	7.200	%	—		—	3,182		79,550
Series O	June & August, 2006	June, 2011	7.375	%	—		—	3,384		84,600
Series P	January, 2007	January, 2012	6.700	%	—		—	5,290		132,250
Total					35,400	$	885,000	23,942	$	598,546

     On October 9, 2012, the Company completed the redemption of its 6.70% Cumulative Preferred Stock, Series P, at its par value of $132.3 million. The Company reported the excess of the redemption amount over the carrying amount of $3.8 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

     On September 14, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 5.75% Cumulative Preferred Stock, Series U, at $25.00 per depositary share.

     On June 15, 2012, the Company completed the redemption of its 7.00% Cumulative Preferred Stock, Series H, at its par value of $158.5 million and its 6.875% Cumulative Preferred Stock, Series I, at its par value of $68.6 million. The Company reported the excess of the redemption amount over the carrying amount of $8.1 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year months ended December 31, 2012.

     On May 14, 2012, the Company issued $350.0 million or 14.0 million depositary shares, each representing 1/1,000 of a share of the 6.00% Cumulative Preferred Stock, Series T, at $25.00 per depositary share.

     During February, 2012, the Company completed the redemption of its 7.20% Cumulative Preferred Stock, Series M, at its par value of $79.6 million and its 7.375% Cumulative Preferred Stock, Series O, at its par value of $84.6 million. The Company reported the excess of the redemption amount over the carrying amount of $5.3 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

     On January 18, 2012, the Company issued $230.0 million or 9.2 million depositary shares, each representing 1/1,000 of a share of the 6.45% Cumulative Preferred Stock, Series S, at $25.00 per depositary share.

     On October 15, 2010, the Company issued $75.0 million or 3.0 million depositary shares, each representing 1/1,000 of a share of the 6.875% Cumulative Preferred Stock, Series R, at $25.00 per depositary share.

     On November 8, 2010, the Company completed the redemption of its 7.60% Cumulative Preferred Stock, Series L, at its par value of $48.4 million. The Company reported the excess of the redemption amount over the carrying amount of $1.6 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

     On June 7, 2010, the Company completed the redemption of its 7.950% Cumulative Preferred Stock, Series K, at its par value of $54.1 million. The Company reported the excess of the redemption amount over the carrying amount of $1.9 million, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

     The Company paid $52.0 million, $41.8 million and $42.7 million in distributions to its preferred shareholders for the years ended December 31, 2012, 2011 and 2010, respectively.

     Holders of the Company's preferred stock will not be entitled to vote on most matters, except under certain conditions. In the event of a cumulative arrearage equal to six quarterly dividends, the holders of the preferred stock will have the right to elect two additional members to serve on the Company's Board of Directors until all events of default have been cured. At December 31, 2012, there were no dividends in arrears.

     Except under certain conditions relating to the Company's qualification as a REIT, the preferred stock is not redeemable prior to the previously noted redemption dates. On or after the respective redemption dates, the respective series of preferred stock will be redeemable, at the option of the Company, in whole or in part, at $25.00 per depositary share, plus any accrued and unpaid dividends. The Company had $28.1 million and $19.7 million of deferred costs in connection with the issuance of preferred stock as of December 31, 2012 and 2011, respectively, which the Company will report as additional non-cash distributions upon notice of its intent to redeem such shares.

Common stock

     The Company's Board of Directors previously authorized the repurchase, from time to time, of up to 6.5 million shares of the Company's common stock on the open market or in privately negotiated transactions. During the year ended December 31, 2011, the Company repurchased 591,500 shares of common stock at an aggregate cost of $30.3 million. Since inception of the program, the Company has repurchased an aggregate of 4.9 million shares of common stock at an aggregate cost of $183.9 million or an average cost per share of $37.64. Under existing board authorizations, the Company can repurchase an additional 1.6 million shares. No shares of common stock were repurchased under this program during the years ended December 31, 2012 and 2010.

     The Company paid $42.7 million ($1.76 per common share), $43.0 million ($1.76 per common share) and $43.3 million ($1.76 per common share) in distributions to its common shareholders for the years ended December 31, 2012, 2011 and 2010, respectively. The portion of the distributions classified as ordinary income was 100.0% for the years ended December 31, 2012, 2011 and 2010. No portion of the distributions was classified as long-term capital gain income for the years ended December 31, 2012, 2011 and 2010. The percentages in the two preceding sentences are unaudited.

Equity stock

     In addition to common and preferred stock, the Company is authorized to issue 100.0 million shares of Equity Stock. The Articles of Incorporation provide that the Equity Stock may be issued from time to time in one or more series and give the Board of Directors broad authority to fix the dividend and distribution rights, conversion and voting rights, redemption provisions and liquidation rights of each series of Equity Stock.

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Noncontrolling Interests

12 Months Ended

Dec. 31, 2012

Noncontrolling Interests [Abstract]

Noncontrolling Interests

7. Noncontrolling interests

     As described in Note 2, the Company reports noncontrolling interests within equity in the consolidated financial statements, but separate from the Company's shareholders' equity. In addition, net income allocable to noncontrolling interests is shown as a reduction from net income in calculating net income allocable to common shareholders.

Common partnership units

     The Company presents the accounts of PSB and the Operating Partnership on a consolidated basis. Ownership interests in the Operating Partnership that can be redeemed for common stock, other than PSB's interest, are classified as noncontrolling interests — common units in the consolidated financial statements. Net income allocable to noncontrolling interests — common units consists of the common units' share of the consolidated operating results after allocation to preferred units and shares. Beginning one year from the date of admission as a limited partner (common units) and subject to certain limitations described below, each limited partner other than PSB has the right to require the redemption of its partnership interest.

     A limited partner (common units) that exercises its redemption right will receive cash from the Operating Partnership in an amount equal to the market value (as defined in the Operating Partnership Agreement) of the partnership interests redeemed. In lieu of the Operating Partnership redeeming the common units for cash, PSB, as general partner, has the right to elect to acquire the partnership interest directly from a limited partner exercising its redemption right, in exchange for cash in the amount specified above or by issuance of one share of PSB common stock for each unit of limited partnership interest redeemed.

     A limited partner (common units) cannot exercise its redemption right if delivery of shares of PSB common stock would be prohibited under the applicable articles of incorporation, or if the general partner believes that there is a risk that delivery of shares of common stock would cause the general partner to no longer qualify as a REIT, would cause a violation of the applicable securities laws, or would result in the Operating Partnership no longer being treated as a partnership for federal income tax purposes.

     At December 31, 2012, there were 7,305,355 common units owned by PS, which are accounted for as noncontrolling interests. On a fully converted basis, assuming all 7,305,355 noncontrolling interests — common units were converted into shares of common stock of PSB at December 31, 2012, the noncontrolling interests —common units would convert into 23.1% of the shares of common stock then outstanding. Combined with PS's existing common stock ownership, on a fully converted basis, PS has a combined ownership of 41.5% of the Company's common equity. At the end of each reporting period, the Company determines the amount of equity (book value of net assets) which is allocable to the noncontrolling interest based upon the ownership interest, and an adjustment is made to the noncontrolling interest, with a corresponding adjustment to paid-in capital, to reflect the noncontrolling interests' equity interest in the Company.

Preferred partnership units

     Through the Operating Partnership, the Company had the following preferred units outstanding as of December 31, 2012 and 2011:

					December 31, 2012			December 31, 2011
		Earliest Potential	Dividend		Units	Amount		Units		Amount
Series	Issuance Date	Redemption Date	Rate		Outstanding	(in thousands)		Outstanding	(in thousands)
Series N	December, 2005	December, 2010	7.125	%	—	$	—	223,300	$	5,583
Total					—	$	—	223,300	$	5,583

     On June 8, 2012, the Company redeemed 223,300 units of its 7.125% Series N Cumulative Redeemable Preferred Units for $5.6 million. The Company reported the excess of the redemption amount over the carrying amount of $149,000, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2012.

     In February, 2011, the Company paid an aggregate of $39.1 million to repurchase 1,710,000 units of its 7.50% Series J Cumulative Redeemable Preferred Units and 203,400 units of its 6.55% Series Q Cumulative Redeemable Preferred Units for a weighted average purchase price of $20.43 per unit. The aggregate par value of the repurchased preferred units was $47.8 million, which generated a gain of $7.4 million, net of original issuance costs of $1.4 million, which was added to net income allocable to common shareholders and unit holders for the year ended December 31, 2011.

     On May 12, 2010, the Company redeemed 800,000 units of its 7.950% Series G Cumulative Redeemable Preferred Units for $20.0 million. The Company reported the excess of the redemption amount over the carrying amount of $582,000, equal to the original issuance costs, as a reduction of net income allocable to common shareholders and unit holders for the year ended December 31, 2010.

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Related Party Transactions

12 Months Ended

Dec. 31, 2012

Related Party Transactions [Abstract]

Related Party Transactions

8. Related party transactions

     The Operating Partnership manages industrial, office and retail facilities for PS. These facilities, all located in the United States, operate under the "Public Storage" or "PS Business Parks" names. The PS Business Parks name and logo is owned by PS and licensed to the Company under a non-exclusive, royalty-free license agreement. The license can be terminated by either party for any reason with six months written notice.

     Under the property management contract with PS, the Operating Partnership is compensated based on a percentage of the gross revenues of the facilities managed. Under the supervision of the property owners, the Operating Partnership coordinates rental policies, rent collections, marketing activities, the purchase of equipment and supplies, maintenance activities, and the selection and engagement of vendors, suppliers and independent contractors. In addition, the Operating Partnership assists and advises the property owners in establishing policies for the hire, discharge and supervision of employees for the operation of these facilities, including property managers and leasing, billing and maintenance personnel.

     The property management contract with PS is for a seven-year term with the agreement automatically extending for an additional one-year period upon each one-year anniversary of its commencement (unless cancelled by either party). Either party can give notice of its intent to cancel the agreement upon expiration of its current term. Management fee revenues under this contract were $649,000, $684,000 and $672,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

     PS also provides property management services for the self-storage component of two assets owned by the Company. These self-storage facilities, located in Palm Beach County, Florida, operate under the "Public Storage" name.

     Under the property management contract, PS is compensated based on a percentage of the gross revenues of the facilities managed. Under the supervision of the Company, PS coordinates rental policies, rent collections, marketing activities, the purchase of equipment and supplies, maintenance activities, and the selection and engagement of vendors, suppliers and independent contractors. In addition, PS is responsible in establishing the policies for the hire, discharge and supervision of employees for the operation of these facilities, including on-site managers, assistant managers and associate managers.

     Either the Company or PS can cancel the property management contract upon 60 days' notice. Management fee expenses under the contract were $55,000, $52,000 and $48,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

     Pursuant to a cost sharing and administrative services agreement, the Company shares costs with PS for certain administrative services, which are allocated to PS in accordance with a methodology intended to fairly allocate those costs. These costs totaled $441,000, $442,000 and $543,000 for the years ended December 31, 2012, 2011 and 2010, respectively.

     The Company had amounts due from PS of $243,000 and $205,000 at December 31, 2012 and 2011, respectively, for these contracts, as well as for certain operating expenses paid by the Company on behalf of PS.

     On February 9, 2011, the Company entered into an agreement with PS to borrow $121.0 million with a maturity date of August 9, 2011 at an interest rate of LIBOR plus 0.85%. The Company repaid, in full, the note payable to PS upon maturity. Interest expense under this note payable was $664,000 for the year ended December 31, 2011.

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Stock Compensation

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

Stock Compensation

10. Stock compensation

     PSB has a 2003 Stock Option and Incentive Plan (the "2003 Plan") covering 1.5 million shares of PSB's common stock. Under the 2003 Plan, PSB has granted non-qualified options to certain directors, officers and key employees to purchase shares of PSB's common stock at a price not less than the fair market value of the common stock at the date of grant. Additionally, under the 2003 Plan, PSB has granted restricted stock units to officers and key employees. Effective February 20, 2012, PSB has a 2012 Equity and Performance-Based Incentive Compensation Plan (the "2012 Plan") covering 1.0 million shares of PSB's common stock. Under the 2012 Plan, PSB has granted non-qualified options to certain directors to purchase shares of PSB's common stock at a price not less than the fair market value of the common stock at the date of grant. Additionally, under the 2012 Plan, PSB has granted restricted shares of common stock to certain directors.

     Options under the 2003 Plan and 2012 Plan vest over a five-year period from the date of grant at the rate of one fifth per year and expire 10 years after the date of grant. Generally, restricted stock units granted are subject to a six-year vesting schedule, none in year one and 20% for each of the next five years. Certain restricted stock unit grants are subject to a three-year vesting schedule with 33.3% vesting for each of the three years.

     The weighted average grant date fair value of options granted in the years ended December 31, 2012, 2011 and 2010 were $4.85 per share, $5.38 per share and $6.08 per share, respectively. The Company has calculated the fair value of each option grant on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions used for grants for the years ended December 31, 2012, 2011 and 2010, respectively; a dividend yield of 2.6%, 2.9% and 3.3%; expected volatility of 13.4%, 13.9% and 17.5%; expected life of five years; and risk-free interest rates of 0.9%, 1.7% and 2.4%.

     The estimated grant-date fair value of restricted stock units is recognized as compensation expense over the applicable vesting period, net of estimates for future forfeitures. Fair value is determined based upon the closing trading price of our common shares on the grant date. The employer portion of payroll taxes is expensed as incurred. The straight-line attribution method is used with respect to option and restricted stock unit grants that are earned solely based upon the passage of time and continued employment. Performance - based restricted stock unit grants are amortized using the accelerated attribution method, with each vesting amortized separately over the individual vesting period.

     The weighted average grant date fair value of restricted stock units granted during the years ended December 31, 2012, 2011 and 2010 were $65.14, $51.63 and $54.44, respectively. The Company calculated the fair value of each restricted stock unit grant using the market value on the date of grant.

     At December 31, 2012, there were a combined total of 975,000 options and restricted stock units authorized to grant. Information with respect to outstanding options and nonvested restricted stock units granted under the 2003 Plan and 2012 Plan is as follows:

					Weighted		Aggregate
				Weighted	Average		Intrinsic
	Number of			Average	Remaining		Value
Options:	Options			Exercise Price	Contract Life		(in thousands)
Outstanding at December 31, 2009	542,752		$	39.43
Granted	291,000		$	52.79
Exercised	(243,936	)	$	31.90
Forfeited	(12,000	)	$	58.19
Outstanding at December 31, 2010	577,816		$	48.95
Granted	14,000		$	60.66
Exercised	(24,600	)	$	42.67
Forfeited	—		$	—
Outstanding at December 31, 2011	567,216		$	49.51
Granted	44,000		$	66.69
Exercised	(143,043	)	$	41.30
Forfeited	(13,600	)	$	61.05
Outstanding at December 31, 2012	454,573		$	53.41	6.07 Years	$	5,436
Exercisable at December 31, 2012	229,173		$	51.70	4.54 Years	$	3,146

				Weighted
	Number of			Average Grant
Restricted Stock Units:	Units			Date Fair Value
Nonvested at December 31, 2009	119,091		$	53.64
Granted	13,900		$	54.44
Vested	(44,857	)	$	53.84
Forfeited	(2,460	)	$	55.90
Nonvested at December 31, 2010	85,674		$	53.60
Granted	8,700		$	51.63
Vested	(29,890	)	$	55.88
Forfeited	(5,260	)	$	52.70
Nonvested at December 31, 2011	59,224		$	52.24
Granted	17,800		$	65.14
Vested	(20,094	)	$	51.36
Forfeited	(3,840	)	$	53.95
Nonvested at December 31, 2012	53,090		$	55.69

     Effective January 1, 2012, the Company entered into a performance-based restricted stock unit program, the Senior Management Long-Term Equity Incentive Program for 2012-2015 ("LTEIP"), with selected employees of the Company. Under the LTEIP, the Company established a targeted restricted stock unit award for selected employees, which would be earned only if the Company achieved defined targets during 2012 to 2015. The first type of award is an annual award following the end of each of the four years in the program, with the award subject to and based on the achievement of defined targets during the previous year. The second type of award is an award based on achieving defined targets during the cumulative four-year period 2012-2015. In the event the defined target is not achieved for an annual award, the shares allocated for award for such year are added to the shares that may be received if the four-year target is achieved. Both types of restricted stock unit awards vest in three equal annual installments beginning one year from the date of award. Up to approximately 38,449 restricted stock units would be granted for each of the four years assuming achievement was met and up to approximately 312,220 restricted stock units would be granted for the cumulative four-year period assuming achievement was met. The target for 2012 was not achieved and therefore the shares allocated for 2012 were added to the shares that may be received if the four-year target is achieved. Net compensation expense of $3.9 million related to the LTEIP was recognized during the year ended December 31, 2012.

     Included in the Company's consolidated statements of income for the years ended December 31, 2012, 2011 and 2010 was $419,000, $486,000 and $509,000, respectively, in net compensation expense related to stock options. Net compensation expense of $4.7 million (includes $3.9 million from the LTEIP noted above,) $920,000 and $1.5 million related to restricted stock units was recognized during the years ended December 31, 2012, 2011 and 2010, respectively.

     As of December 31, 2012, there was $979,000 of unamortized compensation expense related to stock options expected to be recognized over a weighted average period of 2.6 years. As of December 31, 2012, there was $23.8 million (includes $21.6 million from the LTEIP noted above) of unamortized compensation expense related to restricted stock units expected to be recognized over a weighted average period of 5.8 years.

     Cash received from 143,043 stock options exercised during the year ended December 31, 2012 was $5.9 million. Cash received from 24,600 stock options exercised for the year ended December 31, 2011 was $1.1 million. Cash received from 243,936 stock options exercised during the year ended December 31, 2010 was $7.8 million. The aggregate intrinsic value of the stock options exercised during the years ended December 31, 2012, 2011 and 2010 was $3.4 million, $457,000 and $5.3 million, respectively.

     During the year ended December 31, 2012, 20,094 restricted stock units vested; in settlement of these units, 13,248 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2012 was $1.3 million. During the year ended December 31, 2011, 29,890 restricted stock units vested; in settlement of these units, 18,907 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2011 was $1.7 million. During the year ended December 31, 2010, 44,857 restricted stock units vested; in settlement of these units, 27,732 shares were issued, net of shares applied to payroll taxes. The aggregate fair value of the shares vested for the year ended December 31, 2010 was $2.4 million.

     In May of 2004, the shareholders of the Company approved the issuance of up to 70,000 shares of common stock under the Retirement Plan for Non-Employee Directors (the "Director Plan"). Under the Director Plan, the Company grants 1,000 shares of common stock for each year served as a director up to a maximum of 5,000 shares issued upon retirement. In December of 2011, the Director Plan was amended to increase the maximum shares from 5,000 shares to 7,000 shares, 1,000 shares of common stock for each year served as a director. Beginning in 2012, all grants of common stock to directors were under the 2012 Plan. The Company recognizes compensation expense with regards to grants to be issued in the future under the Director Plan. As a result, included in the Company's consolidated statements of income was $287,000, $559,000 and $153,000 in compensation expense for the years ended December 31, 2012, 2011 and 2010, respectively. As of December 31, 2012, 2011 and 2010, there was $1.2 million, $514,000 and $339,000, respectively, of unamortized compensation expense related to these shares. In April, 2012, the Company issued 14,000 shares to two directors upon retirement with an aggregate fair value of $956,000. In January, 2011, the Company issued 5,000 shares to a director upon retirement with an aggregate fair value of $290,000. No shares were issued during the years ended December 31, 2010.

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Real Estate Facilities (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended					12 Months Ended		12 Months Ended			12 Months Ended		12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Austin Multi-Tenant Flex Buildings [Member]	Dec. 19, 2012 Austin Multi-Tenant Flex Buildings [Member] sqft item	Dec. 31, 2012 Kent Valley Industrial Park [Member]	Jul. 24, 2012 Kent Valley Industrial Park [Member] sqft item	Dec. 31, 2012 Northern California Bay Area Portfolio [Member]	Dec. 31, 2011 Northern California Bay Area Portfolio [Member]	Dec. 20, 2011 Northern California Bay Area Portfolio [Member] sqft	Dec. 31, 2012 Las Colinas Office Building [Member]	Oct. 13, 2011 Las Colinas Office Building [Member] sqft	Dec. 31, 2012 MICC [Member]	Aug. 19, 2011 MICC [Member] sqft	Dec. 31, 2010 Miami International Commerce Development [Member] sqft	Dec. 31, 2012 Warren Building [Member]	Jun. 01, 2011 Warren Building [Member] sqft	Dec. 31, 2012 Westpark Business Campus [Member]	Dec. 15, 2010 Westpark Business Campus [Member] sqft item	Dec. 31, 2012 Tysons Corporate Center [Member]	Jul. 30, 2010 Tysons Corporate Center [Member] sqft item	Dec. 31, 2012 Parklawn Business Park [Member]	Jun. 18, 2010 Parklawn Business Park [Member] sqft	Dec. 31, 2012 Austin Portfolio [Member]	Apr. 21, 2010 Austin Portfolio [Member] sqft	Dec. 31, 2012 Shady Grove Executive Center [Member]	Mar. 16, 2010 Shady Grove Executive Center [Member] sqft	Oct. 31, 2012 Quail Valley Business Park [Member] sqft	Dec. 31, 2012 Quail Valley Business Park [Member]	Aug. 31, 2011 Westchase Corporate Park [Member] item sqft	Dec. 31, 2012 Westchase Corporate Park [Member]	Jan. 31, 2010 Houston Office Building [Member] sqft	Dec. 31, 2012 Houston Office Building [Member]
Real Estate Facilities [Line Items]
Federal income tax basis of real estate facilities	$ 2,000,000,000								$ 2,000,000,000
Percentage of properties encumbered by mortgage debt									23.00%
Acquisition/disposal date of real estate												Dec. 19, 2012		Jul. 24, 2012		Dec. 20, 2011			Oct. 13, 2011		Aug. 19, 2011			Jun. 01, 2011		Dec. 15, 2010		Jul. 30, 2010		Jun. 18, 2010		Apr. 21, 2010		Mar. 16, 2010			Oct. 01, 2012		Aug. 01, 2011		Jan. 01, 2010
Number of buildings acquired													3		8												7		2
Leasable space (in square feet)													226,000		958,000			5,300,000		80,000		46,000	75,000		140,000		735,000		270,000		232,000		704,000		350,000	66,000		177,000		131,000
Credit received for committed tenant improvements and lease commissions													592,000												298,000		1,900,000						129,000		1,600,000
Contractual purchase price of real estate	51,858,000				553,162,000				51,858,000	553,162,000	298,526,000		14,900,000		37,600,000		520,000,000	520,000,000		2,800,000		3,500,000			27,100,000		140,000,000		35,400,000		23,400,000		42,900,000		60,000,000
Acquisition transaction costs									350,000	3,100,000	3,300,000
Mortgage note payable	268,102,000				282,084,000				268,102,000	282,084,000								250,000,000
Unsecured debt	200,000,000				250,000,000				200,000,000	250,000,000								250,000,000
Length of debt term (in years)																3 years
Rental income	89,224,000	87,020,000	85,627,000	84,677,000	74,563,000	76,463,000	72,970,000	73,461,000	346,548,000	297,457,000	276,276,000					42,500,000	1,200,000
Net loss									95,372,000	102,640,000	102,022,000					7,200,000	838,000
Number of buildings sold																																						13
Sale price of real estate																																				2,300,000		9,800,000		10,000,000
Gain on sale of real estate facility									935,000	2,717,000	5,153,000																									935,000		2,700,000		5,200,000
Tenant reimbursements from discontinued operations										$ 617,000	$ 852,000

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Stock Compensation (Summary Of Stock Options Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation and Retirement Disclosure [Abstract]
Number of Options, Outstanding	567,216	577,816	542,752
Number of Options, Granted	44,000	14,000	291,000
Number of Options, Exercised	(143,043)	(24,600)	(243,936)
Number of Options, Forfeited	(13,600)		(12,000)
Number of Options, Outstanding	454,573	567,216	577,816
Number of Options, Exercisable at December 31, 2012	229,173
Weighted Average Exercise Price, Outstanding	$ 49.51	$ 48.95	$ 39.43
Weighted Average Exercise Price, Granted	$ 66.69	$ 60.66	$ 52.79
Weighted Average Exercise Price, Exercised	$ 41.30	$ 42.67	$ 31.90
Weighted Average Exercise Price, Forfeited	$ 61.05		$ 58.19
Weighted Average Exercise Price, Outstanding	$ 53.41	$ 49.51	$ 48.95
Weighted Average Exercise Price, Exercisable at December 31, 2012	$ 51.70
Weighted Average Remaining Contract Life, Outstanding at December 31, 2012	6 years 26 days
Weighted Average Remaining Contract Life, Exercisable at December 31, 2012	4 years 6 months 15 days
Aggregate Intrinsic Value, Outstanding at December 31, 2012	$ 5,436
Aggregate Intrinsic Value, Exercisable at December 31, 2012	$ 3,146

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Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2012

Summary Of Significant Accounting Policies [Abstract]

Basis Of Presentation

Basis of presentation

     The accompanying consolidated financial statements include the accounts of PSB and the Operating Partnership. All significant inter-company balances and transactions have been eliminated in the consolidated financial statements.

Noncontrolling Interests

Noncontrolling Interests

     The Company's noncontrolling interests are reported as a component of equity separate from the parent's equity. Purchases or sales of equity interests that do not result in a change in control are accounted for as equity transactions. In addition, net income attributable to the noncontrolling interest is included in consolidated net income on the face of the income statement and, upon a gain or loss of control, the interest purchased or sold, as well as any interest retained, is recorded at fair value with any gain or loss recognized in earnings.

Use Of Estimates

Use of estimates

     The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates.

Allowance For Doubtful Accounts

Allowance for doubtful accounts

     The Company monitors the collectability of its receivable balances including the deferred rent receivable on an ongoing basis. Based on these reviews, the Company maintains an allowance for doubtful accounts for estimated losses resulting from the possible inability of tenants to make contractual rent payments to the Company. A provision for doubtful accounts is recorded during each period. The allowance for doubtful accounts, which represents the cumulative allowances less write-offs of uncollectible rent, is netted against tenant and other receivables on the consolidated balance sheets. Tenant receivables are net of an allowance for uncollectible accounts totaling $400,000 at December 31, 2012 and 2011.

Financial Instruments

Financial instruments

     The methods and assumptions used to estimate the fair value of financial instruments are described below. The Company has estimated the fair value of financial instruments using available market information and appropriate valuation methodologies. Considerable judgment is required in interpreting market data to develop estimates of market value. Accordingly, estimated fair values are not necessarily indicative of the amounts that could be realized in current market exchanges. The Company determines the estimated fair value of financial assets and liabilities utilizing a hierarchy of valuation techniques based on whether the inputs to a fair value measurement are considered to be observable or unobservable in a marketplace. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions. This hierarchy requires the use of observable market data when available. The following is the fair value hierarchy:

· Level 1—quoted prices for identical instruments in active markets

· Level 2—quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which significant inputs and significant value drivers are observable in active markets; and· Level 3—fair value measurements derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable

     Financial assets that are exposed to credit risk consist primarily of cash and cash equivalents and receivables. The Company considers all highly liquid investments with a remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents, which consist primarily of money market investments, are only invested in entities with an investment grade rating. Receivables are comprised of balances due from a large number of customers. Balances that the Company expects to become uncollectible are reserved for or written off. Due to the short period to maturity of the Company's cash and cash equivalents, accounts receivable, other assets and accrued and other liabilities, the carrying values as presented on the consolidated balance sheets are reasonable estimates of fair value.

     Carrying values of the Company's mortgage notes payable, unsecured credit facility and term loan are deemed to approximate fair value. The characteristics of these financial instruments, market data and other comparative metrics utilized in determining these fair values are "Level 2" inputs.

Real Estate Facilities

Real estate facilities

     Real estate facilities are recorded at cost. Costs related to the renovation or improvement of the properties are capitalized. Expenditures for repairs and maintenance are expensed as incurred. Expenditures that are expected to benefit a period greater than two years and exceed $2,000 are capitalized and depreciated over their estimated useful life. Buildings and improvements are depreciated using the straight-line method over their estimated useful lives, which generally range from five to 30 years. Transaction costs, which include tenant improvements and lease commissions, in excess of $1,000 for leases with terms greater than one year are capitalized and depreciated over their estimated useful lives. Transaction costs less than $1,000 or leases of one year or less are expensed as incurred.

Properties Held For Disposition

Properties held for disposition

     An asset is classified as an asset held for disposition when it meets certain requirements, which include, among other criteria, the approval of the sale of the asset, the marketing of the asset for sale and the expectation by the Company that the sale will likely occur within the next 12 months. Upon classification of an asset as held for disposition, depreciation of the asset is ceased, the operating results of the asset are included in discontinued operations for all periods presented and the net book value of the asset is included on the balance sheet as properties held for disposition.

Intangible Assets/Liabilities

Intangible assets/liabilities

     Intangible assets and liabilities include above-market and below-market in-place lease values of acquired properties based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) management's estimate of fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. The capitalized above-market and below-market lease values (included in other assets and accrued liabilities in the accompanying consolidated balance sheets) are amortized to rental income over the remaining non-cancelable terms of the respective leases. The Company recorded net amortization reducing rental income of $501,000, $843,000 and $571,000 of intangible assets and liabilities resulting from the above-market and below-market lease values during the years ended December 31, 2012, 2011 and 2010, respectively. As of December 31, 2012, the value of in-place leases resulted in a net intangible asset of $5.2 million, net of $4.7 million of accumulated amortization with a weighted average amortization period of 6.4 years, and a net intangible liability of $4.7 million, net of $3.0 million of accumulated amortization with a weighted average amortization period of 5.0 years. As of December 31, 2011, the value of in-place leases resulted in a net intangible asset of $6.9 million, net of $2.3 million of accumulated amortization and a net intangible liability of $6.4 million, net of $1.1 million of accumulated amortization.

Evaluation Of Asset Impairment

Evaluation of asset impairment

     The Company evaluates its assets used in operations for impairment by identifying indicators of impairment and by comparing the sum of the estimated undiscounted future cash flows for each asset to the asset's carrying value. When indicators of impairment are present and the sum of the estimated undiscounted future cash flows is less than the carrying value of such asset, an impairment loss is recorded equal to the difference between the asset's current carrying value and its value based on discounting its estimated future cash flows. In addition, the Company evaluates its assets held for disposition for impairment. Assets held for disposition are reported at the lower of their carrying value or fair value, less cost of disposition. At December 31, 2012, the Company did not consider any assets to be impaired.

Asset Impairment Due to Casualty Loss

Asset impairment due to casualty loss

     It is the Company's policy to record as a casualty loss or gain, in the period the casualty occurs, the differential between (a) the book value of assets destroyed and (b) any insurance proceeds that the Company expects to receive in accordance with its insurance contracts. Potential proceeds from insurance that are subject to any uncertainties, such as interpretation of deductible provisions of the governing agreements, the estimation of costs of restoration, or other such items, are treated as contingent proceeds and not recorded until the uncertainties are satisfied.

For the years ended December 31, 2012, 2011 and 2010 no material casualty losses were incurred.

Stock Compensation

Stock compensation

     All share-based payments to employees, including grants of employee stock options, are recognized as stock compensation in the Company's income statement based on their grant date fair values. See Note 10.

Revenue And Expense Recognition

Revenue and expense recognition

     The Company must meet four basic criteria before revenue can be recognized: persuasive evidence of an arrangement exists; the delivery has occurred or services rendered; the fee is fixed or determinable; and collectability is reasonably assured. All leases are classified as operating leases. Rental income is recognized on a straight-line basis over the terms of the leases. Straight-line rent is recognized for all tenants with contractual fixed increases in rent that are not included on the Company's credit watch list. Deferred rent receivable represents rental revenue recognized on a straight-line basis in excess of billed rents. Reimbursements from tenants for real estate taxes and other recoverable operating expenses are recognized as rental income in the period the applicable costs are incurred. Property management fees are recognized in the period earned.

     Costs incurred in connection with leasing (primarily tenant improvements and lease commissions) are capitalized and amortized over the lease period.

Gains From Sales Of Real Estate Facilities

Gains from sales of real estate facilities

     The Company recognizes gains from sales of real estate facilities at the time of sale using the full accrual method, provided that various criteria related to the terms of the transactions and any subsequent involvement by the Company with the properties sold are met. If the criteria are not met, the Company defers the gains and recognizes them when the criteria are met or uses the installment or cost recovery methods as appropriate under the circumstances.

General And Administrative Expenses

General and administrative expenses

     General and administrative expenses include executive and other compensation, office expense, professional fees, acquisition transaction costs, state income taxes and other such administrative items.

Income Taxes

Income taxes

     The Company has qualified and intends to continue to qualify as a REIT, as defined in Section 856 of the Internal Revenue Code. As a REIT, the Company is not subject to federal income tax to the extent that it distributes its REIT taxable income to its shareholders. A REIT must distribute at least 90% of its taxable income each year. In addition, REITs are subject to a number of organizational and operating requirements. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to federal income tax (including any applicable alternative minimum tax) based on its taxable income using corporate income tax rates. Even if the Company qualifies for taxation as a REIT, the Company may be subject to certain state and local taxes on its income and property and to federal income and excise taxes on its undistributed taxable income. The Company believes it met all organization and operating requirements to maintain its REIT status during 2012, 2011 and 2010 and intends to continue to meet such requirements. Accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements.

     The Company can recognize a tax benefit only if it is "more likely than not" that a particular tax position will be sustained upon examination or audit. To the extent that the "more likely than not" standard has been satisfied, the benefit associated with a position is measured as the largest amount that is greater than 50% likely of being recognized upon settlement. As of December 31, 2012, the Company did not recognize any tax benefit for uncertain tax positions.

Accounting For Preferred Equity Issuance Costs

Accounting for preferred equity issuance costs

     The Company records issuance costs as a reduction to paid-in capital on its balance sheet at the time the preferred securities are issued and reflects the carrying value of the preferred equity at the stated value. The Company records issuance costs as non-cash preferred equity distributions at the time it notifies the holders of preferred stock or units of its intent to redeem such shares or units.

Net Income Allocation

Net income allocation

Net income was allocated as follows for the years ended December 31, (in thousands):

		2012		2011			2010
Net income allocable to noncontrolling interests:
Noncontrolling interests — common units:
Continuing operations	$	5,744	$	14,838		$	10,307
Discontinued operations		226		705			1,287
Total net income allocable to noncontrolling interests —
common units		5,970		15,543			11,594
Noncontrolling interests — preferred units:
Distributions to preferred unit holders		174		398			4,521
Issuance costs related to the redemption of preferred units		149		—			582
Gain on repurchase of preferred units, net of issuance costs		—		(7,389	)		—
Total net income allocable to noncontrolling interests —
preferred units		323		(6,991	)		5,103
Total net income allocable to noncontrolling interests		6,293		8,552			16,697
Net income allocable to PS Business Parks, Inc.:
Preferred shareholders:
Distributions to preferred shareholders		51,969		41,799			42,730
Issuance costs related to the redemption of preferred stock		17,167		—			3,484
Total net income allocable to preferred shareholders		69,136		41,799			46,214
Restricted stock unit holders:
Continuing operations		135		121			135
Discontinued operations		3		6			17
Total net income allocable to restricted stock unit holders		138		127			152
Common shareholders:
Continuing operations		19,057		49,796			34,635
Discontinued operations		748		2,366			4,324
Total net income allocable to common shareholders		19,805		52,162			38,959
Total net income allocable to PS Business Parks, Inc		89,079		94,088			85,325
Net income	$	95,372	$	102,640		$	102,022

Net Income Per Common Share

Net income per common share

     Per share amounts are computed using the number of weighted average common shares outstanding. "Diluted" weighted average common shares outstanding includes the dilutive effect of stock options and restricted stock units under the treasury stock method. "Basic" weighted average common shares outstanding excludes such effect. The Company's restricted stock units are participating securities and are included in the computation of basic and diluted weighted average common shares outstanding. The Company's restricted stock unit holders are paid non-forfeitable dividends in excess of the expense recorded which results in a reduction in net income allocable to common shareholders and unit holders. Earnings per share has been calculated as follows for the years ended December 31, (in thousands, except per share amounts):

		2012		2011		2010
Net income allocable to common shareholders	$	19,805	$	52,162	$	38,959
Weighted average common shares outstanding:
Basic weighted average common shares outstanding		24,234		24,516		24,546
Net effect of dilutive stock compensation — based on
treasury stock method using average market price		89		83		141
Diluted weighted average common shares outstanding		24,323		24,599		24,687
Net income per common share — Basic	$	0.82	$	2.13	$	1.59
Net income per common share — Diluted	$	0.81	$	2.12	$	1.58

     Options to purchase 51,200, 92,000 and 78,000 shares for the years ended December 31 2012, 2011 and 2010, respectively, were not included in the computation of diluted net income per share because such options were considered anti-dilutive.

Segment Reporting

Segment reporting

The Company views its operations as one segment.

Reclassifications

Reclassifications

     Certain reclassifications have been made to the consolidated financial statements for 2011 and 2010 in order to conform to the 2012 presentation.

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Noncontrolling Interests (Tables)

12 Months Ended

Dec. 31, 2012

Noncontrolling Interests [Abstract]

Operating Partnership Of Preferred Units Outstanding

					December 31, 2012			December 31, 2011
		Earliest Potential	Dividend		Units	Amount		Units		Amount
Series	Issuance Date	Redemption Date	Rate		Outstanding	(in thousands)		Outstanding	(in thousands)
Series N	December, 2005	December, 2010	7.125	%	—	$	—	223,300	$	5,583
Total					—	$	—	223,300	$	5,583

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Shareholders' Equity (Schedule Of Preferred Stock Outstanding) (Details) (USD $) In Thousands, except Share data, unless otherwise specified			0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Oct. 15, 2010 Series R [Member]	Dec. 31, 2012 Series R [Member]	Dec. 31, 2011 Series R [Member]	Jan. 18, 2012 Series S [Member]	Dec. 31, 2012 Series S [Member]	May 14, 2012 Series T [Member]	Dec. 31, 2012 Series T [Member]	Sep. 14, 2012 Series U [Member]	Dec. 31, 2012 Series U [Member]	Jun. 15, 2012 Series H [Member]	Dec. 31, 2012 Series H [Member]	Dec. 31, 2011 Series H [Member]	Jun. 15, 2012 Series I [Member]	Dec. 31, 2012 Series I [Member]	Dec. 31, 2011 Series I [Member]	Feb. 29, 2012 Series M [Member]	Dec. 31, 2012 Series M [Member]	Dec. 31, 2011 Series M [Member]	Feb. 29, 2012 Series O [Member]	Dec. 31, 2012 Series O [Member]	Dec. 31, 2011 Series O [Member]	Oct. 09, 2012 Series P [Member]	Dec. 31, 2012 Series P [Member]	Dec. 31, 2011 Series P [Member]
Class of Stock [Line Items]
Issuance Date				October 15, 2010			January 18, 2012		May 14, 2012		September 14, 2012		January & October, 2004			April, 2004			May, 2005			June & August, 2006			January, 2007
Earliest Potential Redemption Date				Oct. 01, 2015			Jan. 01, 2017		May 01, 2017		Sep. 01, 2017		Jan. 01, 2009			Apr. 01, 2009			May 01, 2010			Jun. 01, 2011		Oct. 09, 2012	Jan. 01, 2012
Dividend Rate			6.875%	6.875%		6.45%	6.45%	6.00%	6.00%	5.75%	5.75%	7.00%	7.00%		6.875%	6.875%		7.20%	7.20%		7.375%	7.375%		6.70%	6.70%
Shares Outstanding	35,400	23,942		3,000	3,000		9,200		14,000		9,200			6,341			2,745			3,182			3,384			5,290
Amount	$ 885,000	$ 598,546	$ 75,000	$ 75,000	$ 75,000	$ 230,000	$ 230,000	$ 350,000	$ 350,000	$ 230,000	$ 230,000			$ 158,520			$ 68,626			$ 79,550			$ 84,600			$ 132,250

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Bank Loans (Details) (USD $)	12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Feb. 09, 2011	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Term Loan Agreement [Member]	Dec. 31, 2011 Term Loan Agreement [Member]	Dec. 20, 2011 Term Loan Agreement [Member]	Dec. 31, 2012 Term Loan Agreement [Member] Maximum [Member]	Dec. 31, 2012 Term Loan Agreement [Member] Minimum [Member]
Line of Credit Facility [Line Items]
Line of credit, expiration date	Aug. 01, 2015
Credit Facility, borrowing limit	$ 250,000,000
Credit Facility, frequency of interest payment	monthly
Spread over LIBOR	1.10%		0.85%	1.85%	1.00%	1.20%			2.25%	1.15%
Credit Facility, percentage of commitment fees	0.15%			0.45%	0.15%
Credit Facility, amount outstanding		185,000,000
Credit Facility, interest rate		1.41%
Unsecured debt	200,000,000	250,000,000				200,000,000	250,000,000	250,000,000
Term Loan, interest rate						1.41%	1.50%
Unamortized commitments fees	$ 791,000	$ 1,100,000				$ 383,000	$ 729,000
Length of debt term (in years)						3 years
Term loan, maturity date						Dec. 31, 2014
Length of maturity date extension term						1 year

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Consolidated Statement Of Equity (USD $)	Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Cumulative Net Income [Member]	Cumulative Distributions [Member]	Total PS Business Parks, Inc.'s Shareholders' Equity [Member]	Noncontrolling Interests [Member]	Total
Balances, value at Dec. 31, 2009	$ 626,046,000	$ 243,000	$ 548,393,000	$ 699,291,000	$ (658,294,000)	$ 1,215,679,000	$ 249,958,000	$ 1,465,637,000
Balances, shares at Dec. 31, 2009	25,042	24,399,509
Repurchase of common stock, shares								0
Issuance of preferred stock, net of issuance costs, value	75,000,000		(2,487,000)			72,513,000		72,513,000
Issuance of preferred stock , net of issuance costs, shares	3,000
Redemption of preferred stock, net of issuance costs, value	(102,500,000)		3,484,000		(3,484,000)	(102,500,000)		(102,500,000)
Redemption of preferred stock, net of issuance costs, shares	(4,100)
Redemption of preferred units, net of issuance costs			582,000			582,000	(20,582,000)	(20,000,000)
Exercise of stock options, value		3,000	7,780,000			7,783,000		7,783,000
Exercise of stock options, shares		243,936						243,936
Stock compensation, net, value			1,031,000			1,031,000		1,031,000
Stock compensation, net, shares		27,732
Net income				85,325,000		85,325,000	16,697,000	102,022,000
Distributions:
Preferred stock					(42,730,000)	(42,730,000)		(42,730,000)
Common stock					(43,254,000)	(43,254,000)		(43,254,000)
Noncontrolling interests							(17,377,000)	(17,377,000)
Adjustment to noncontrolling interests in underlying operating partnership			(901,000)			(901,000)	901,000	(901,000)
Balances, value at Dec. 31, 2010	598,546,000	246,000	557,882,000	784,616,000	(747,762,000)	1,193,528,000	229,597,000	1,423,125,000
Balances, shares at Dec. 31, 2010	23,942	24,671,177
Repurchase of preferred units, net of issuance costs			10,107,000			10,107,000	(49,194,000)	(39,087,000)
Repurchase of common stock, value		(6,000)	(30,246,000)			(30,252,000)		(30,252,000)
Repurchase of common stock, shares		(591,500)
Exercise of stock options, value			1,050,000			1,050,000		1,050,000
Exercise of stock options, shares		24,600						24,600
Stock compensation, net, value			1,218,000			1,218,000		1,218,000
Stock compensation, net, shares		23,907
Net income				94,088,000		94,088,000	8,552,000	102,640,000
Distributions:
Preferred stock					(41,799,000)	(41,799,000)		(41,799,000)
Common stock					(43,046,000)	(43,046,000)		(43,046,000)
Noncontrolling interests							(13,254,000)	(13,254,000)
Adjustment to noncontrolling interests in underlying operating partnership			(5,689,000)			(5,689,000)	5,689,000	(5,689,000)
Balances, value at Dec. 31, 2011	598,546,000	240,000	534,322,000	878,704,000	(832,607,000)	1,179,205,000	181,390,000	1,360,595,000
Balances, shares at Dec. 31, 2011	23,942	24,128,184
Repurchase of common stock, shares								0
Issuance of preferred stock, net of issuance costs, value	810,000,000		(25,608,000)			784,392,000		784,392,000
Issuance of preferred stock , net of issuance costs, shares	32,400
Redemption of preferred stock, net of issuance costs, value	(523,546,000)		17,167,000		(17,167,000)	(523,546,000)		(523,546,000)
Redemption of preferred stock, net of issuance costs, shares	(20,942)
Redemption of preferred units, net of issuance costs			149,000			149,000	(5,732,000)	(5,583,000)
Exercise of stock options, value		2,000	5,905,000			5,907,000		5,907,000
Exercise of stock options, shares		143,043						143,043
Stock compensation, net, value			4,807,000			4,807,000		4,807,000
Stock compensation, net, shares		27,248
Net income				89,079,000		89,079,000	6,293,000	95,372,000
Distributions:
Preferred stock					(51,969,000)	(51,969,000)		(51,969,000)
Common stock					(42,684,000)	(42,684,000)		(42,684,000)
Noncontrolling interests							(13,030,000)	(13,030,000)
Adjustment to noncontrolling interests in underlying operating partnership			349,000			349,000	(349,000)	349,000
Balances, value at Dec. 31, 2012	$ 885,000,000	$ 242,000	$ 537,091,000	$ 967,783,000	$ (944,427,000)	$ 1,445,689,000	$ 168,572,000	$ 1,614,261,000
Balances, shares at Dec. 31, 2012	35,400	24,298,475

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Leasing Activity

12 Months Ended

Dec. 31, 2012

Leasing Activity [Abstract]

Leasing Activity

4. Leasing activity

     The Company leases space in its real estate facilities to tenants primarily under non-cancelable leases generally ranging from one to 10 years. Future minimum rental revenues, excluding recovery of operating expenses under these leases, are as follows as of December 31, 2012 (in thousands):

2013	$	244,595
2014		179,923
2015		124,246
2016		84,954
2017		55,384
Thereafter		92,496
Total	$	781,598

     In addition to minimum rental payments, certain tenants reimburse the Company for their pro rata share of specified operating expenses. Such reimbursements amounted to $71.9 million, $59.6 million and $57.2 million, for the years ended December 31, 2012, 2011 and 2010, respectively. These amounts are included as rental income in the accompanying consolidated statements of income.

     Leases accounting for 6.1% of total leased square footage are subject to termination options which include leases accounting for 2.7% of total leased square footage having termination options exercisable through December 31, 2013 (unaudited). In general, these leases provide for termination payments should the termination options be exercised. The above table is prepared assuming such options are not exercised.

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Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2012

Shareholders' Equity [Abstract]

Schedule Of Preferred Stock Outstanding

					December 31, 2012			December 31, 2011
		Earliest Potential Dividend			Shares		Amount	Shares		Amount
Series	Issuance Date	Redemption Date	Rate		Outstanding	(in thousands) Outstanding			(in thousands)
Series R	October, 2010	October, 2015	6.875	%	3,000	$	75,000	3,000	$	75,000
Series S	January, 2012	January, 2017	6.450	%	9,200		230,000	—		—
Series T	May, 2012	May, 2017	6.000	%	14,000		350,000	—		—
Series U	September, 2012	September, 2017	5.750	%	9,200		230,000	—		—
Series H	January & October, 2004	January, 2009	7.000	%	—		—	6,341		158,520
Series I	April, 2004	April, 2009	6.875	%	—		—	2,745		68,626
Series M	May, 2005	May, 2010	7.200	%	—		—	3,182		79,550
Series O	June & August, 2006	June, 2011	7.375	%	—		—	3,384		84,600
Series P	January, 2007	January, 2012	6.700	%	—		—	5,290		132,250
Total					35,400	$	885,000	23,942	$	598,546

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Real Estate Facilities (Condensed Results Of Operations For The Properties Sold) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Real Estate Facilities [Abstract]
Rental income	$ 281	$ 1,459	$ 2,232
Cost of operations	(143)	(808)	(1,243)
Depreciation	(96)	(291)	(514)
Income from discontinued operations	$ 42	$ 360	$ 475

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Real Estate And Accumulated Depreciation

12 Months Ended

Dec. 31, 2012

Real Estate And Accumulated Depreciation [Abstract]

Real Estate and Accumulated Depreciation

PS BUSINESS PARKS, INC.

SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION DECEMBER 31, 2012 (DOLLARS IN THOUSANDS)

									Cost
									Capitalized
									Subsequent to		Gross Amount at Which Carried at
					Initial Cost to Company				Acquisition		December 31, 2012
							Buildings		Buildings				Buildings						Depreciable
							and		and				and				Accumulated		Lives
Description	Location		Encumbrances		Land		Improvements		Improvements		Land		Improvements		Total		Depreciation	Year(s) Acquired	(Years)
Mesa	Mesa, AZ	$	—	$	675	$	1,692	$	2,758	$	675	$	4,450	$	5,125	$	3,390	1997	5-30
Corporate/Metro Park Phoenix	Phoenix, AZ		—		5,130		17,514		2,823		5,130		20,337		25,467		10,467	1999/2003	5-30
Tempe/McKellips	Tempe, AZ		—		195		522		587		195		1,109		1,304		758	1997	5-30
University	Tempe, AZ		—		2,805		7,107		6,124		2,805		13,231		16,036		8,827	1997	5-30
Concord Business Park	Concord, CA		—		12,454		20,491		534		12,454		21,025		33,479		1,343	2011	5-30
Bayview Business Park	Fremont, CA		7,300		4,990		4,831		42		4,990		4,873		9,863		362	2011	5-30
Christy Business Park	Fremont, CA		14,200		11,450		16,254		186		11,450		16,440		27,890		1,138	2011	5-30
Industrial Drive Distribution Center	Fremont, CA		5,300		7,482		6,812		101		7,482		6,913		14,395		522	2011	5-30
Bay Center Business Park	Hayward, CA		27,500		19,052		50,501		333		19,052		50,834		69,886		3,719	2011	5-30
Cabot Distribution Center	Hayward, CA		9,300		5,859		10,811		270		5,859		11,081		16,940		517	2011	5-30
Diablo Business Park	Hayward, CA		—		9,102		15,721		427		9,102		16,148		25,250		1,243	2011	5-30
Eden Landing	Hayward, CA		4,800		3,275		6,174		8		3,275		6,182		9,457		520	2011	5-30
Hayward Business Park	Hayward, CA		46,400		28,256		54,418		795		28,256		55,213		83,469		2,994	2011	5-30
Huntwood Business Park	Hayward, CA		11,600		7,391		11,819		303		7,391		12,122		19,513		727	2011	5-30
Parkway Commerce	Hayward, CA		—		4,398		10,433		4,127		4,398		14,560		18,958		8,091	1997	5-30
Dixon Landing Business Park	Milpitas, CA		30,000		26,301		21,121		552		26,301		21,673		47,974		1,874	2011	5-30
Monterey/Calle	Monterey, CA		—		288		706		303		288		1,009		1,297		597	1997	5-30
Port of Oakland	Oakland, CA		10,800		5,638		11,066		383		5,638		11,449		17,087		802	2011	5-30
Northpointe Business Center	Sacramento, CA		—		3,031		13,826		5,618		3,031		19,444		22,475		11,934	1999	5-30
Sacramento/Northgate	Sacramento, CA		—		1,710		4,567		2,959		1,710		7,526		9,236		4,944	1997	5-30
Charcot Business Park	San Jose, CA		10,300		8,086		11,546		576		8,086		12,122		20,208		984	2011	5-30
Las Plumas	San Jose, CA		—		4,379		12,889		5,660		4,379		18,549		22,928		12,099	1998	5-30
Little Orchard Distribution Center	San Jose, CA		5,900		7,725		3,846		35		7,725		3,881		11,606		277	2011	5-30
Montague Industrial Park	San Jose, CA		14,200		14,476		12,807		149		14,476		12,956		27,432		1,109	2011	5-30
Oakland Road	San Jose, CA		—		3,458		8,765		2,704		3,458		11,469		14,927		6,603	1997	5-30
Rogers Ave	San Jose, CA		—		3,540		4,896		409		3,540		5,305		8,845		1,982	2006	5-30
Doolittle Business Park	San Leandro, CA		4,500		3,929		6,231		180		3,929		6,411		10,340		419	2011	5-30
San Ramon/Norris Canyon	San Ramon, CA		—		1,486		3,642		1,189		1,486		4,831		6,317		2,750	1997	5-30
Commerce Park	Santa Clara, CA		—		17,218		21,914		3,570		17,218		25,484		42,702		13,739	2007	5-30
Santa Clara Tech Park	Santa Clara, CA		—		7,673		15,645		3,551		7,673		19,196		26,869		9,603	2000	5-30
Walsh at Lafayette	Santa Clara, CA		19,300		13,437		17,890		80		13,437		17,970		31,407		2,048	2011	5-30
Airport Blvd	So. San Francisco, CA		—		899		2,387		638		899		3,025		3,924		1,672	1997	5-30
So. San Francisco/Produce	So. San Francisco, CA		—		776		1,886		411		776		2,297		3,073		1,267	1997	5-30
Kifer Industrial Park	Sunnyvale, CA		28,600		13,227		37,874		15		13,227		37,889		51,116		2,152	2011	5-30
Buena Park Industrial Center	Buena Park, CA		—		3,245		7,703		2,147		3,245		9,850		13,095		5,457	1997	5-30
Carson	Carson, CA		—		990		2,496		1,330		990		3,826		4,816		2,305	1997	5-30
Cerritos Business Center	Cerritos, CA		—		4,218		10,273		3,524		4,218		13,797		18,015		7,844	1997	5-30
Cerritos/Edwards	Cerritos, CA		—		450		1,217		1,193		450		2,410		2,860		1,366	1997	5-30
Culver City	Culver City, CA		—		3,252		8,157		5,776		3,252		13,933		17,185		8,332	1997	5-30
Corporate Pointe	Irvine, CA		—		6,876		18,519		6,174		6,876		24,693		31,569		14,435	2000	5-30
Laguna Hills Commerce Center	Laguna Hills, CA		—		16,261		39,559		4,341		16,261		43,900		60,161		23,359	1997	5-30

					Cost
					Capitalized
					Subsequent to	Gross Amount at Which Carried at
			Initial Cost to Company		Acquisition	December 31, 2012
				Buildings	Buildings		Buildings				Depreciable
				and	and		and		Accumulated		Lives
Description	Location	Encumbrances	Land	Improvements	Improvements	Land	Improvements	Total	Depreciation	Year(s) Acquired	(Years)
Plaza Del Lago	Laguna Hills, CA	—	2,037	5,051	3,548	2,037	8,599	10,636	5,470	1997	5-30
Canada	Lake Forest, CA	—	5,508	13,785	4,646	5,508	18,431	23,939	10,410	1997	5-30
Monterey Park	Monterey Park, CA	—	3,078	7,862	1,420	3,078	9,282	12,360	5,218	1997	5-30
Orange County Business Center	Orange County, CA	—	9,405	35,746	17,147	9,405	52,893	62,298	36,846	2003	5-30
Orangewood	Orange County, CA	—	2,637	12,291	3,003	2,637	15,294	17,931	7,560	2003	5-30
Kearney Mesa	San Diego, CA	—	2,894	7,089	2,605	2,894	9,694	12,588	5,542	1997	5-30
Lusk	San Diego, CA	—	5,711	14,049	5,240	5,711	19,289	25,000	11,180	1997	5-30
Rose Canyon Business Park	San Diego, CA	—	15,129	20,054	1,856	15,129	21,910	37,039	9,566	2005	5-30
Signal Hill	Signal Hill, CA	—	6,693	12,699	2,241	6,693	14,940	21,633	6,979	1997/2006	5-30
Studio City/Ventura	Studio City, CA	—	621	1,530	375	621	1,905	2,526	1,113	1997	5-30
Torrance	Torrance, CA	—	2,318	6,069	2,665	2,318	8,734	11,052	5,023	1997	5-30
Boca Commerce	Boca Raton, FL	9,036	7,795	9,258	917	7,795	10,175	17,970	3,295	2006	5-30
MICC	Miami, FL	—	89,529	105,370	35,318	89,529	140,688	230,217	69,205	2003/2011	5-30
Wellington	Wellington, FL	9,066	10,845	18,560	1,307	10,845	19,867	30,712	5,952	2006	5-30
Ammendale	Beltsville, MD	—	4,278	18,380	9,511	4,278	27,891	32,169	17,612	1998	5-30
Gaithersburg/Christopher	Gaithersburg, MD	—	475	1,203	535	475	1,738	2,213	1,063	1997	5-30
Metro Park	Rockville, MD	—	33,995	94,463	33,125	33,995	127,588	161,583	69,333	2001	5-30
Parklawn Business Park	Rockville, MD	—	3,387	19,628	2,500	3,387	22,128	25,515	3,755	2010	5-30
Shady Grove	Rockville, MD	—	5,372	50,727	6,614	5,372	57,341	62,713	8,745	2010	5-30
Westech Business Park	Silver Spring, MD	—	25,261	74,572	10,012	25,261	84,584	109,845	40,437	2006	5-30
Cornell Oaks	Beaverton, OR	—	20,616	63,235	17,667	20,616	80,902	101,518	41,662	2001	5-30
Creekside	Beaverton, OR	—	15,007	47,125	22,022	15,007	69,147	84,154	42,633	1998/2000	5-30
Milwaukie	Milwaukie, OR	—	1,125	2,857	1,613	1,125	4,470	5,595	2,627	1997	5-30
Empire Commerce	Dallas, TX	—	304	1,545	814	304	2,359	2,663	1,545	1998	5-30
Northgate	Dallas, TX	—	1,274	5,505	3,731	1,274	9,236	10,510	5,428	1998	5-30
Westwood Business Park	Farmers Branch, TX	—	941	6,884	1,503	941	8,387	9,328	4,026	2003	5-30
Eastgate	Garland, TX	—	480	1,203	568	480	1,771	2,251	1,045	1997	5-30
NFTZ (1)	Irving, TX	—	1,517	6,499	1,836	1,517	8,335	9,852	5,353	1998	5-30
Royal Tech	Irving, TX	—	13,989	54,113	19,760	13,989	73,873	87,862	40,504	1998-2000/2011	5-30
La Prada	Mesquite, TX	—	495	1,235	629	495	1,864	2,359	1,102	1997	5-30
The Summit	Plano, TX	—	1,536	6,654	3,674	1,536	10,328	11,864	6,657	1998	5-30
Richardson/Business Parkway	Richardson, TX	—	799	3,568	2,363	799	5,931	6,730	3,881	1998	5-30
Ben White	Austin, TX	—	1,550	7,015	1,802	1,550	8,817	10,367	4,611	1998	5-30
Lamar Business Park	Austin, TX	—	2,528	6,596	3,978	2,528	10,574	13,102	7,944	1997	5-30
McKalla	Austin, TX	—	1,945	13,212	1,805	1,945	15,017	16,962	5,043	1998/2012	5-30
Rutland	Austin, TX	—	2,022	9,397	3,618	2,022	13,015	15,037	6,515	1998/1999	5-30
Waterford	Austin, TX	—	2,108	9,649	3,206	2,108	12,855	14,963	7,637	1999	5-30
Braker Business Park	Austin, TX	—	1,874	13,990	919	1,874	14,909	16,783	3,213	2010	5-30
McNeil	Austin, TX	—	2,314	17,044	1,512	2,314	18,556	20,870	4,224	1999/2010/2012	5-30
Mopac Business Park	Austin, TX	—	719	3,579	330	719	3,909	4,628	791	2010	5-30
Southpark Business Park	Austin, TX	—	1,266	9,882	748	1,266	10,630	11,896	2,197	2010	5-30
Bren Mar	Alexandria, VA	—	2,197	5,380	3,670	2,197	9,050	11,247	5,358	1997	5-30
Eisenhower	Alexandria, VA	—	1,440	3,635	2,372	1,440	6,007	7,447	3,920	1997	5-30
Beaumont	Chantilly, VA	—	4,736	11,051	1,480	4,736	12,531	17,267	5,431	2006	5-30
Dulles South/Sullyfield	Chantilly, VA	—	1,373	6,810	2,645	1,373	9,455	10,828	5,342	1999	5-30
Lafayette	Chantilly, VA	—	1,680	13,398	4,218	1,680	17,616	19,296	10,731	1999/2000	5-30
Park East	Chantilly, VA	—	3,851	18,029	9,252	3,851	27,281	31,132	13,682	1999	5-30
Fair Oaks Business Park	Fairfax, VA	—	13,598	36,232	5,181	13,598	41,413	55,011	19,935	2004/2007	5-30
Prosperity Business Campus	Fairfax, VA	—	23,147	67,575	24,636	23,147	92,211	115,358	48,017	2001	5-30
Monroe	Herndon, VA	—	6,737	18,911	9,207	6,737	28,118	34,855	17,080	1997/1999	5-30

									Cost
									Capitalized
									Subsequent to		Gross Amount at Which Carried at
					Initial Cost to Company				Acquisition				December 31, 2012
							Buildings		Buildings				Buildings						Depreciable
							and		and				and				Accumulated		Lives
Description	Location		Encumbrances		Land		Improvements		Improvements		Land		Improvements		Total		Depreciation	Year(s) Acquired	(Years)
Gunston	Lorton, VA		—		4,146		17,872		4,489		4,146		22,361		26,507		12,634	1998	5-30
Westpark Business Campus	McLean, VA		—		53,882		111,253		15,612		53,882		126,865		180,747		15,787	2010/2011	5-30
Alban Road	Springfield, VA		—		1,935		4,736		4,618		1,935		9,354		11,289		6,044	1997	5-30
I-95	Springfield, VA		—		3,535		15,672		10,093		3,535		25,765		29,300		17,657	2000	5-30
Northpointe	Sterling, VA		—		2,767		8,778		4,026		2,767		12,804		15,571		8,512	1997/1998	5-30
Shaw Road	Sterling, VA		—		2,969		10,008		3,768		2,969		13,776		16,745		9,254	1998	5-30
Tysons Corporate Center	Vienna, VA		—		9,885		25,302		7,738		9,885		33,040		42,925		4,889	2010	5-30
Woodbridge	Woodbridge, VA		—		1,350		3,398		1,623		1,350		5,021		6,371		3,087	1997	5-30
212th Business Park	Kent, WA		—		19,573		17,695		1,489		19,573		19,184		38,757		461	2012	5-30
Overlake	Redmond, WA		—		27,761		49,353		5,568		27,761		54,921		82,682		26,465	2007	5-30
Renton	Renton, WA		—		330		889		517		330		1,406		1,736		840	1997	5-30
		$	268,102	$	793,352	$	1,801,678	$	433,770	$	793,352	$	2,235,448	$	3,028,800	$	942,639

(1)

The Company owns two properties that are subject to ground leases in Las Colinas, Texas, expiring in 2019 and 2020, each with one 10 year extension option.