Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation. The Company's consolidated financial statements are prepared on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles (“GAAP”). The financial statements reflect the accounts of the Company and its consolidated subsidiaries. The Company consolidates its wholly-owned subsidiaries, partnerships and joint ventures which it controls (i) through voting rights or similar rights or (ii) by means other than voting rights if the Company is the primary beneficiary of a variable interest entity ("VIE"). Entities which the Company does not control and entities which are VIEs in which the Company is not the primary beneficiary are accounted for under appropriate GAAP.
Variable Interest Entity	The Company is the primary beneficiary of certain VIEs as it has a controlling financial interest in these entities. LCIF, which is consolidated and in which the Company has an approximate 96% interest, is a VIE.
Earnings Per Share	Earnings Per Share. Basic net income (loss) per share is computed by dividing net income (loss) reduced by preferred dividends and amounts allocated to certain non-vested share-based payment awards, if applicable, by the weighted-average number of common shares outstanding during the period. Diluted net income (loss) per share amounts are similarly computed but include the effect, when dilutive, of in-the-money common share options and non-vested common shares, OP units and put options of certain convertible securities.
Use of Estimates	Use of Estimates. Management has made a number of significant estimates and assumptions relating to the reporting of assets and liabilities, the disclosure of contingent assets and liabilities and the reported amounts of revenues and expenses to prepare these consolidated financial statements in conformity with GAAP. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the economic environment. Management adjusts such estimates when facts and circumstances dictate. The most significant estimates made include the recoverability of accounts receivable, allocation of property purchase price to tangible and intangible assets acquired and liabilities assumed, the determination of VIEs and which entities should be consolidated, the determination of impairment of long-lived assets and equity method investments, valuation of derivative financial instruments, valuation of awards granted under compensation plans and the useful lives of long-lived assets. Actual results could differ materially from those estimates.
Fair Value Measurements	Fair Value Measurements. The Company follows the guidance in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 820, Fair Value Measurements and Disclosures ("Topic 820"), to determine the fair value of financial and non-financial instruments. Topic 820 defines fair value, establishes a framework for measuring fair value in GAAP and expands disclosures about fair value measurements. Topic 820 establishes a fair value hierarchy that prioritizes observable and unobservable inputs used to measure fair value into three levels: Level 1 - quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities; Level 2 - observable prices that are based on inputs not quoted in active markets, but corroborated by market data; and Level 3 - unobservable inputs, which are used when little or no market data is available. The fair value hierarchy gives the highest priority to Level 1 inputs and the lowest priority to Level 3 inputs. In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible, as well as considering counterparty credit risk. The Company has formally elected to apply the portfolio exception within Topic 820 with respect to measuring counterparty risk for all of its derivative transactions subject to master netting arrangements.
Revenue Recognition	Revenue Recognition. The Company recognizes lease revenue on a straight-line basis over the term of the lease unless another systematic and rational basis is more representative of the time pattern in which the use benefit is derived from the leased property. Revenue is recognized on a contractual basis for leases with escalations tied to a consumer price index with no floor. Renewal options in leases with rental terms that are lower than those in the primary term are excluded from the calculation of straight-line rent if the renewals are not reasonably assured. If the Company funds tenant improvements and the improvements are deemed to be owned by the Company, revenue recognition will commence when the improvements are substantially completed and possession or control of the space is turned over to the tenant. If the Company determines that the tenant allowances are lease incentives, the Company commences revenue recognition when possession or control of the space is turned over to the tenant for tenant work to begin. The lease incentive is recorded as a deferred expense and amortized as a reduction of revenue on a straight-line basis over the respective lease term. The Company recognizes lease termination fees as rental revenue in the period received and writes off unamortized lease-related intangible and other lease-related account balances, provided there are no further Company obligations under the lease. Otherwise, such fees and balances are recognized on a straight-line basis over the remaining obligation period with the termination payments being recorded as a component of rent receivable-deferred on the Consolidated Balance Sheets.
Acquisition of Real Estate	Acquisition of Real Estate. The fair value of the real estate acquired, which includes the impact of fair value adjustments for assumed mortgage debt related to property acquisitions, is allocated to the acquired tangible assets, consisting of land, building and improvements and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, other value of in-place leases and value of tenant relationships, based in each case on their fair values. Prior to January 1, 2018, acquisition and pursuit costs were expensed as incurred and were included in property operating expense in the accompanying Consolidated Statement of Operations, which were $2,171 and $836 for 2017 and 2016, respectively. Effective January 1, 2018, the Company's acquisitions are primarily considered asset acquisitions and acquisition costs are now capitalized. The fair value of the tangible assets of an acquired property (which includes land, building and improvements and fixtures and equipment) is determined by valuing the property as if it were vacant. The “as-if-vacant” value is then allocated to land and building and improvements based on management's determination of relative fair values of these assets. Factors considered by management in performing these analyses include an estimate of carrying costs during the expected lease-up periods considering current market conditions and costs to execute similar leases. In estimating carrying costs, management includes real estate taxes, insurance and other operating expenses and estimates of lost rental revenue during the expected lease-up periods based on current market demand. Management also estimates costs to execute similar leases including leasing commissions. Management generally retains a third party to assist in the allocations. In allocating the fair value of the identified intangible assets and liabilities of an acquired property, above-market and below-market lease values are recorded based on the difference between the current in-place lease rent and management's estimate of current market rents. Below-market lease intangibles are recorded as part of deferred revenue and amortized into rental revenue over the non-cancelable periods and bargain renewal periods of the respective leases. Above-market leases are recorded as part of intangible assets and amortized as a direct charge against rental revenue over the non-cancelable portion of the respective leases. The aggregate value of other acquired intangible assets, consisting of in-place leases and tenant relationship values, is measured by the excess of (1) the purchase price paid for a property over (2) the estimated fair value of the property as if vacant, determined as set forth above. This aggregate value is allocated between in-place lease values and tenant relationship values based on management's evaluation of the specific characteristics of each tenant's lease. The value of in-place leases is amortized to expense over the remaining non-cancelable periods and any bargain renewal periods of the respective leases. The value of tenant relationships is amortized to expense over the applicable lease term plus expected renewal periods. Depreciation is determined by the straight-line method over the remaining estimated economic useful lives of the properties. The Company generally depreciates its real estate assets over periods ranging up to 40 years.
Impairment of Real Estate	Impairment of Real Estate. The Company evaluates the carrying value of all tangible and intangible real estate assets held for investment for possible impairment when an event or change in circumstance has occurred that indicates its carrying value may not be recoverable. The evaluation includes estimating and reviewing anticipated future undiscounted cash flows to be derived from the asset. If such cash flows are less than the asset's carrying value, an impairment charge is recognized to the extent by which the asset's carrying value exceeds its estimated fair value, which may be below the balance of any non-recourse financing. Estimating future cash flows and fair values is highly subjective and such estimates could differ materially from actual results.
Investments in Non-Consolidated Entities	Investments in Non-Consolidated Entities. The Company accounts for its investments in 50% or less owned entities under the equity method, unless consolidation is required. If the Company's investment in the entity is insignificant and the Company has no influence over the control of the entity then the entity is accounted for under the cost method.
Impairment of Equity Method Investments	Impairment of Equity Method Investments. The Company assesses whether there are indicators that the value of its equity method investments may be impaired. An impairment charge is recognized only if the Company determines that a decline in the value of the investment below its carrying value is other-than-temporary. The assessment of impairment is highly subjective and involves the application of significant assumptions and judgments about the Company's intent and ability to recover its investment given the nature and operations of the underlying investment, including the level of the Company's involvement therein, among other factors. To the extent an impairment is deemed to be other-than-temporary, the loss is measured as the excess of the carrying amount of the investment over the estimated fair value of the investment.
Acquisition, Development and Construction Arrangements	Acquisition, Development and Construction Arrangements. The Company evaluates loans receivable where the Company participates in residual profits through loan provisions or other contracts to ascertain whether the Company has the same risks and rewards as an owner or a joint venture partner. Where the Company concludes that such arrangements are more appropriately treated as an investment in real estate, the Company reflects such loan receivable as an equity investment in real estate under construction in the Consolidated Balance Sheets. In these cases, no interest income is recorded on the loan receivable and the Company records capitalized interest during the construction period. In arrangements where the Company engages a developer to construct a property or provide funds to a tenant to develop a property, the Company will capitalize the funds provided to the developer/tenant and internal costs of interest and real estate taxes, if applicable, during the construction period.
Properties Held For Sale	Properties Held For Sale. Assets and liabilities of properties that meet various held for sale criteria, including whether it is probable that a sale will occur within 12 months, are presented separately in the Consolidated Balance Sheets. The operating results of these properties are reflected as discontinued operations in the Consolidated Statements of Operations only if the sale of these assets represents a strategic shift in operations; if not, the operating results are included in continuing operations. Properties classified as held for sale are carried at the lower of net carrying value or estimated fair value less costs to sell and depreciation and amortization are no longer recognized. Properties that do not meet the held for sale criteria are accounted for as operating properties.
Deferred Expenses	Deferred Expenses. Deferred expenses consist primarily of revolving line of credit debt and leasing costs. Debt costs are amortized using the straight-line method, which approximates the interest method, over the terms of the debt instruments and leasing costs are amortized over the term of the related lease.
Derivative Financial Instruments	Derivative Financial Instruments. The Company accounts for its interest rate swap agreements in accordance with FASB ASC Topic 815, Derivatives and Hedging ("Topic 815"). In accordance with Topic 815, these agreements are carried on the balance sheet at their respective fair values, as an asset if fair value is positive, or as a liability if fair value is negative. If the interest rate swap is designated as a cash flow hedge, the effective portion of the interest rate swap's change in fair value is reported as a component of other comprehensive income (loss); the ineffective portion, if any, is recognized in earnings as an increase or decrease to interest expense. Upon entering into hedging transactions, the Company documents the relationship between the interest rate swap agreement and the hedged item. The Company also documents its risk-management policies, including objectives and strategies, as they relate to its hedging activities. The Company assesses, both at inception of a hedge and on an ongoing basis, whether or not the hedge is highly effective. The Company will discontinue hedge accounting on a prospective basis with changes in the estimated fair value reflected in earnings when (1) it is determined that the derivative is no longer effective in offsetting cash flows of a hedged item (including forecasted transactions), (2) it is no longer probable that the forecasted transaction will occur or (3) it is determined that designating the derivative as an interest rate swap is no longer appropriate. The Company does and may continue to utilize interest rate swap and cap agreements to manage interest rate risk, but does not anticipate entering into derivative transactions for speculative trading purposes.
Stock Compensation	Stock Compensation. The Company maintains an equity participation plan. Non-vested share grants generally vest either based upon (1) time, (2) performance and/or (3) market conditions. Options granted under the plan in 2010 vested over a five-year period and expire ten years from the date of grant. Options granted under the plan in 2008 vested upon attainment of certain market performance measures and expired ten years from the date of grant. All share-based payments to employees, including grants of employee stock options, are recognized in the Consolidated Statements of Operations based on their fair values.
Tax Status	Tax Status. The Company has made an election to qualify, and believes it is operating so as to qualify, as a REIT for federal income tax purposes. Accordingly, the Company generally will not be subject to federal income tax, provided that distributions to its shareholders equal at least the amount of its REIT taxable income as defined under Sections 856 through 860 of the Code. The Company is permitted to participate in certain activities from which it was previously precluded in order to maintain its qualification as a REIT, so long as these activities are conducted in entities which elect to be treated as taxable REIT subsidiaries under the Code. As such, the Company is subject to federal and state income taxes on the income from these activities. Income taxes, primarily related to the Company's taxable REIT subsidiaries, are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled.
Cash and Cash Equivalents	Cash and Cash Equivalents. The Company considers all highly liquid instruments with maturities of three months or less from the date of purchase to be cash equivalents.
Restricted Cash	Restricted Cash. Restricted cash is comprised primarily of cash balances held in escrow by lenders.
Environmental Matters	Environmental Matters. Under various federal, state and local environmental laws, statutes, ordinances, rules and regulations, an owner of real property may be liable for the costs of removal or remediation of certain hazardous or toxic substances at, on, in or under such property as well as certain other potential costs relating to hazardous or toxic substances. These liabilities may include government fines, penalties and damages for injuries to persons and adjacent property. Such laws often impose liability without regard to whether the owner knew of, or was responsible for, the presence or disposal of such substances. Although most of the tenants of properties in which the Company has an interest are primarily responsible for any environmental damage and claims related to the leased premises, in the event of the bankruptcy or inability of the tenant of such premises to satisfy any obligations with respect to such environmental liability, or if the tenant is not responsible, the Company's property owner subsidiary may be required to satisfy any such obligations, should they exist. In addition, the property owner subsidiary, as the owner of such a property, may be held directly liable for any such damages or claims irrespective of the provisions of any lease.
Segment Reporting	Segment Reporting. The Company operates generally in one industry segment, single-tenant real estate assets.
Reclassification	Reclassifications. Certain amounts included in prior years' financial statements have been reclassified to conform to the current year's presentation.
Recently Issued Accounting Guidance	New Accounting Standards Adopted in 2018. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which addresses how certain cash receipts and cash payments are presented and classified in the statement of cash flows. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which clarifies guidance on the classification and presentation of changes in restricted cash. Restricted cash balances are now included along with cash and cash equivalents as of the end of the period and beginning of period, respectively, in the Company's consolidated statement of cash flows for all periods presented. In addition, separate line items showing changes in restricted cash balances are now eliminated from the Company's consolidated statement of cash flows. These ASUs were effective for fiscal years beginning after December 15, 2017, including interim periods within those years. Entities must apply the guidance retrospectively to all periods presented but may apply it prospectively if retrospective application would be impracticable. The Company adopted these ASUs effective January 1, 2018 on a retrospective basis. The effect of the adoption resulted in (1) a $109 and $4,537 change in cash flows from operating activities for 2017 and 2016, respectively, (2) a $(23,958) and $21,571 change in cash flows from investing activities for 2017 and 2016, respectively, and (3) a $(2,899) and $(5,603) change in cash flows from financing activities for 2017 and 2016, respectively. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which clarifies the definition of a business when evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The ASU was effective for reporting periods beginning after December 15, 2017. The Company expects that acquisitions of real estate or in-substance real estate will not meet the revised definition of a business and thus will be treated as asset acquisitions. Acquisition costs for those acquisitions that are not businesses will be capitalized rather than expensed. The Company adopted this guidance effective January 1, 2018 on a prospective basis. The Company's property acquisitions in 2018 were accounted for as asset acquisitions. The Company's adoption of this guidance did not have a material impact on its consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), as subsequently amended, which amends the guidance for revenue recognition to eliminate the industry-specific revenue recognition guidance and replace it with a principle based approach for determining revenue recognition. The new guidance was effective for reporting periods beginning after December 15, 2017. The Company’s revenue-producing contracts are primarily leases that are not within the scope of this standard as leases are excluded from ASU 2014-09. Under ASU 2014-09, revenue recognition for real estate sales is largely based on the transfer of control and the buyer having the ability to direct the use of, or obtain substantially all of the remaining benefit from, the asset (which generally will occur on the closing date); the factor of continuing involvement is no longer a specific consideration for the timing of recognition. The Company adopted ASU 2014-09 effective January 1, 2018 using the modified retrospective approach. As the majority of the Company’s revenue is from rental income related to leases, the adoption of the ASU did not have a material impact on its consolidated financial statements. In February 2017, the FASB issued ASU 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Topic 610-20), which requires that all entities account for the derecognition of a business in accordance with ASC 810, including instances in which the business is considered in-substance real estate. The ASU requires the Company to measure at fair value any retained interest in a partial sale of real estate. The Company adopted ASU 2017-05 effective January 1, 2018 using the modified retrospective approach, however there was no impact to prior balances as there were no open contracts at the date of adoption. During 2018, the Company entered into a transaction in which it contributed consolidated properties to a newly-formed joint venture and acquired a 20% interest in the joint venture. See note 7. Recently Issued Accounting Guidance. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize a right of use asset and related lease liability for those leases classified as operating leases at the commencement date that have lease terms of more than 12 months and amends certain lessor guidance. The Company expects the ASU to result in the recognition of a right-of-use asset and related liability to primarily account for the Company's future obligations under its ground lease arrangements for which the Company is the lessee. The Company estimates that its initial right-of-use asset and lease liability will be within a range of $35,000 to $45,000 at adoption. From a lessor perspective, the Company expects that lease components will primarily be recognized on a straight-line basis over the lease term. ASU 2016-02 originally stated that companies would be required to bifurcate certain lease revenues between lease and non-lease components; however, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements in July 2018, which allows lessors a practical expedient by class of underlying assets to account for lease and non-lease components as a single lease component if certain criteria are met. Additionally, ASU 2016-02 requires that the Company capitalize, as initial direct costs, only those costs that are incurred due to the execution of a lease. Historically, the Company has capitalized lease commissions and "other" lease related costs, primarily legal expenses. Effective January 1, 2019, the Company will not capitalize these "other" costs, however, the Company does not believe these will be material. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those years. ASU 2016-02 originally required a modified retrospective method of adoption; however, under ASU 2018-11 companies may elect to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company will adopt this new guidance on January 1, 2019 utilizing the cumulative-effect adjustment outlined in ASU 2018-11. In addition, the Company will elect several practical expedients afforded to it at implementation. In August 2017, the FASB issued ASU-2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, which amends the hedge accounting recognition and presentation requirements in Topic 815. The adoption of this guidance on January 1, 2019 did not have a material impact on the Company's consolidated financial statements.