Acquisitions (Tables)

9 Months Ended

Sep. 30, 2011

Business Combinations [Abstract]

Acquired operating properties from unrelated third parties

Property	Property Type	Date of Acquisition	Number of Buildings	Rentable Square Feet	Percentage Occupied as of September 30, 2011	Purchase Price (in  millions)(1)
250 Brannan Street	Office	January 28, 2011
San Francisco, CA			1	92,948	100.0%	$	33.0
10210, 10220, and 10230 NE Points Drive; 3933 Lake Washington Boulevard NE	Office	April 21, 2011
Kirkland, WA(2)			4	279,924	89.6%	100.1
10770 Wateridge Circle	Office	May 12, 2011
San Diego, CA			1	174,310	97.5%	32.7
601 108th Avenue N.E.	Office	June 3, 2011
Bellevue, WA			1	488,470	88.1%	215.0
4040 Civic Center Drive	Office	June 9, 2011
San Rafael, CA			1	126,787	93.1%	32.2
201 Third Street	Office	September 15, 2011
San Francisco, CA (3)			1	311,545	90.3%	103.3
Total			9	1,473,984		$	516.3

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(1) Excludes acquisition-related costs.

(2) In connection with this acquisition, we assumed secured debt with an outstanding principal balance of $30.0 million and recorded a premium of $1.0 million in connection with recording this debt at fair value on the acquisition date (see Note 5).

(3) As of September 30, 2011, this property was temporarily being held in a separate VIE to facilitate a potential Section 1031 Exchange (see Note 1).

Fair values of assets acquired and liabilities assumed

The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the respective acquisition dates:

	601 108th Avenue N.E., Bellevue, WA(1)		201 Third Street San Francisco, CA (1)		All Other Acquisitions(2)		Total
Assets
Land(3)	$	—	$	19,260	$	36,740	$	56,000
Buildings and improvements(4)	214,095		84,018		143,545		441,658
Undeveloped land	—		—		2,560		2,560
Deferred leasing costs and acquisition-related intangible assets(5)	13,790		8,700		17,500		39,990
Total assets acquired	227,885		111,978		200,345		540,208
Liabilities
Deferred revenue and acquisition-related intangible liabilities(6)	12,850		8,700		1,390		22,940
Secured debt(7)	—		—		30,997		30,997
Accounts payable, accrued expenses and other liabilities	2,380		76		2,059		4,515
Total liabilities assumed	15,230		8,776		34,446		58,452
Net assets and liabilities acquired(8)	$	212,655	$	103,202	$	165,899	$	481,756

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(1) The purchase of 601 108th Avenue N.E., Bellevue, WA, and 201 Third Street, San Francisco, CA, represent the two largest acquisitions and 61.7% of the total aggregate purchase price of the properties acquired during the nine months ended September 30, 2011.

(2) The purchase price of all other acquisitions completed during the nine months ended September 30, 2011 were individually less than 5% and in the aggregate less than 10% of the Company's total assets as of December 31, 2010.

(3) In connection with the acquisition of 601 108th Avenue N.E., Bellevue, WA, we assumed the lessee's obligations under a noncancellable ground lease that is scheduled to expire in November 2093 (see Notes 3 and 11).

(4) Represents buildings, building improvements and tenant improvements.

(5) Represents in-place leases (approximately $25.2 million with a weighted average amortization period of 3.9 years), above-market leases (approximately $6.8 million with a weighted average amortization period of 4.5 years), and leasing commissions (approximately $7.9 million with a weighted average amortization period of 2.6 years).

(6) Represents below-market leases (approximately $17.7 million with a weighted average amortization period of 3.8 years) and an above-market ground lease obligation (approximately $5.2 million with a weighted average amortization period of 82.5 years), under which we are the lessee.

(7) Represents the mortgage loan, which includes an unamortized premium recorded at the date of acquisition of approximately $1.0 million in connection with recording this debt at fair value, assumed in connection with the properties acquired in April 2011 (see Note 5).

(8) Reflects the purchase price net of assumed secured debt and other lease-related obligations.