Equity method investment summarized financial information debt.

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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- Definition

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 21, 2020	Jul. 31, 2013
Schedule of Equity Method Investments [Line Items]
Carrying Amount	$ 411,110	$ 389,811
Company's Share of unconsolidated real estate venture Income (Loss)	(26,697)	(18,584)	$ (9,922)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 961,509	963,018
Commerce Square Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	70.00%
Carrying Amount	$ 247,798	253,128
Company's Share of unconsolidated real estate venture Income (Loss)	(15,501)	(9,150)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 213,069	219,168
Mid-Atlantic Office Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	40.00%			40.00%
Carrying Amount	$ 31,680	32,996
Company's Share of unconsolidated real estate venture Income (Loss)	932	96
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 123,015	120,831
Brandywine - AI Venture LLC
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	50.00%
Carrying Amount	$ 0	10,302
Company's Share of unconsolidated real estate venture Income (Loss)	(721)	185	(2,800)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 0	0
Herndon Innovation Center Metro Portfolio Venture, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	15.00%
Carrying Amount	$ 15,844	16,019
Company's Share of unconsolidated real estate venture Income (Loss)	(174)	(358)	(498)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 207,302	207,302
MAP Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	50.00%
Carrying Amount	$ (24,396)	(11,516)
Company's Share of unconsolidated real estate venture Income (Loss)	(8,683)	(6,570)	(6,102)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 184,263	185,000
PJP VII
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	25.00%
Company's Share of unconsolidated real estate venture Income (Loss)			190
PJP II
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	30.00%
Company's Share of unconsolidated real estate venture Income (Loss)			81
PJP VI
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	25.00%
Company's Share of unconsolidated real estate venture Income (Loss)			(185)
4040 Wilson Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	50.00%				50.00%
Carrying Amount	$ 31,059	34,454
Company's Share of unconsolidated real estate venture Income (Loss)	(2,258)	(2,162)	(368)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 145,000	141,857
1919 Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	50.00%
Carrying Amount	$ 13,791	15,434
Company's Share of unconsolidated real estate venture Income (Loss)	427	59	328
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 88,860	88,860
3025 JFK Venture
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	55.00%
Carrying Amount	$ 56,370	0
Company's Share of unconsolidated real estate venture Income (Loss)	(118)	0	0
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 0	0
JBG 51 N Street
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	70.00%
Carrying Amount	$ 21,213	21,237
Company's Share of unconsolidated real estate venture Income (Loss)	(402)	(457)	(313)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 0	0
JBG 1250 First Street Office
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	70.00%
Carrying Amount	$ 17,751	17,757
Company's Share of unconsolidated real estate venture Income (Loss)	(199)	(227)	$ (255)
Unconsolidated Real Estate Venture Debt at 100%, gross	$ 0	$ 0