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Investment in Unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands |  |  |  |  |  | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2021 USD ($) | Dec. 14, 2021 USD ($) ft² loanExtension yr Rate | Sep. 01, 2021 USD ($) ft² | Aug. 31, 2021 USD ($) ft² years loanExtension | Mar. 30, 2021 USD ($) ft² | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 15, 2021 | Oct. 29, 2021 ft² | Jun. 11, 2021 ft² | Feb. 25, 2021 ft²
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net |  | $ 3,267,914 |  |  |  |  |  | $ 3,267,914 |  | $ 2,909,081 |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 0.775% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Sale of Equity Method Investments |  |  |  |  |  |  |  | 17,789 |  | 0 |  | $ 0 |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  |  | 98,152 |  | 172,436 |  | 87,392 |  |  |  |
Income (Loss) from Equity Method Investments |  |  |  |  |  |  |  | (2,570) |  | (85,110) |  | 46,592 |  |  |  |
Capital distributions from unconsolidated joint ventures |  |  |  |  |  |  |  | 122 |  | 55,298 |  | 136,807 |  |  |  |
Proceeds from sales of real estate |  |  |  |  |  |  |  | 179,887 |  | 519,303 |  | 90,824 |  |  |  |
Repayments of Secured Debt |  |  |  |  |  |  |  | $ 832,296 |  | $ 17,168 |  | 46,173 |  |  |  |
7750 Wisconsin Avenue [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  | 733,000 |  |
360 Park South Avenue |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  | 42.21% |  |  |
Net Rentable Area (in sf) | ft² |  |  |  | 450,000 |  |  |  |  |  |  |  |  |  |  |  |
Number of floors |  |  |  | 20 |  |  |  |  |  |  |  |  |  |  |  |
number of investors |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |
Debt - Total loan amount |  |  |  | $ 220,000 |  |  |  |  |  |  |  |  |  |  |  |
360 Park South Avenue | Adjustable Rate Loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | Rate |  |  |  | 2.40% |  |  |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |
Extension Option (in years) | yr |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |
Debt - Total loan amount |  |  |  | $ 220,000 |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Issuance of Debt |  |  |  | $ 202,000 |  |  |  |  |  |  |  |  |  |  |  |
Gateway Commons Complex [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% | [1] |  |  |  |  | 50.00% | [1] | 55.00% |  |  |  |  |  | 54.00%
Gateway Commons Complex [Member] | Scenario, Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |
Gateway Commons Complex [Member] | Scenario, Plan | 751 Gateway |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 49.00% |  |  |  |  |  | 49.00% |  |  |  |  |  |  |  |
Gateway Commons Complex prior to deferred contribution [Member] [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  | 50.00% |  | 55.00% |  |  |  |  |  |
Platform 16 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [2] | 55.00% |  |  |  |  |  | 55.00% |  |  |  |  |  |  |  |
Annapolis Junction NFM, LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  | 50.00% |  |  | 50.00% | [3] |  |  |  |  |
Contractual Sales Price |  |  |  |  |  |  | $ 65,900 |  |  |  |  |  |  |  |  |
Proceeds from Sale of Equity Method Investments |  |  |  |  |  |  | 17,800 |  |  |  |  |  |  |  |  |
Capital distributions from unconsolidated joint ventures |  |  |  |  |  |  | 5,800 |  |  |  |  |  |  |  |  |
Gain on Sale of Investments |  |  |  |  |  |  | 10,300 | $ 10,300 |  |  |  |  |  |  |  |
Repayments of Secured Debt |  |  |  |  |  |  | $ 15,100 |  |  |  |  |  |  |  |  |
Annapolis Junction NFM, LLC [Member] | Annapolis Junction Building Six and Seven | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  | 247,000 |  |  |  |  |  |  |  |  |
100 Causeway Street [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |
100 Causeway Street [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 634,000 |
Safeco Plaza REIT LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 33.67% | [4] |  | 33.67% |  |  | 33.67% | [4] |  |  |  |  |  |  |
Mortgage notes payable, net |  |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  | 765,000 |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  | $ 72,600 |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  | variable rate equal to the greater of (x) 2.35% or (y) LIBOR plus 2.20% per annum |  |  |  |  |  |  |  |  |  |  |
Aggregate purchase price |  |  |  |  | $ 460,100 |  |  |  |  |  |  |  |  |  |  |
Number of floors |  |  |  |  | 50 |  |  |  |  |  |  |  |  |  |  |
number of investors |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |
Acquisition Costs, Period Cost |  |  |  |  | $ 4,900 |  |  |  |  |  |  |  |  |  |  |
Podium Developer LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  | 50.00% |  | 50.00% |  |  |  |  |  |  |  |
Mortgage notes payable, net |  |  |  |  |  | $ 174,300 |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.25% |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  | 382,000 |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |
Extension Option (in years) | years |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |
360 PAS Holdco LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 42.21% | [5] |  |  |  |  | 42.21% | [5] |  |  |  | 42.21% |  |  |
number of investors |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |
Unconsolidated Joint Ventures [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net |  | $ 3,214,961 |  |  |  |  |  | $ 3,214,961 |  | $ 2,637,911 |  |  |  |  |  |
Income (Loss) from Equity Method Investments |  |  |  |  |  |  |  | (2,570) |  | (85,110) |  | 46,592 |  |  |  |
Impairment loss on investment |  |  |  |  |  |  |  | 0 |  | 60,524 | [6] | 0 |  |  |  |
Gain on Sale of Investments |  |  |  |  |  |  |  | $ 10,257 | [7] | 0 |  | $ 0 |  |  |  |
Unconsolidated Joint Ventures [Member] | Dock 72 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment loss on investment |  |  |  |  |  |  |  |  |  | $ 60,500 |  |  |  |  |  |
Construction in Progress | Gateway Commons Complex [Member] | 751 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 231,000
Company's Share [Member] | Safeco Plaza REIT LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 33.00% |  |  |  |  |  | 33.00% |  |  |  |  |  |  |  |
Company's Share [Member] | Safeco Partner Entity One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |  |  |  |  |
Company's Share [Member] | Safeco Partner Entity Two |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |  |  |  |  |
Company's Share [Member] | 360 Park Avenue South Partners Entity Two |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |  | 1.00% |  |  |
Company's Share [Member] | 360 Park Avenue South Partners Entity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |  | 1.00% |  |  |
Company's Share [Member] | 360 PAS Holdco LLC (indirect ownership) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 5.837% |  |  |  |  |  | 5.837% |  |  |  |  | 5.837% |  |  |
Company's Share [Member] | 360 PAS Holdco LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 35.79% |  |  |  |  |  | 35.79% |  |  |  |  | 35.79% |  |  |
Institutional investor number one | Safeco Plaza REIT LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  | 33.165% |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  | $ 71,900 |  |  |  |  |  |  |  |  |  |  |
Institutional investor number two | Safeco Plaza REIT LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  | 33.165% |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  | $ 71,900 |  |  |  |  |  |  |  |  |  |  |
Institutional investors | 360 PAS Holdco LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  | 58.00% |  |  |
[1] | As a result of the partner’s deferred contribution, the Company owned an approximately 50% and 55% interest in the joint venture at December 31, 2021 and December 31, 2020, respectively.
[2] | This entity is a VIE (See Note 2).
[3] | On March 30, 2021, the Company sold its interest in the joint venture to the partner. See below for additional details.
[4] | The Company’s ownership includes (1) a 33.0% direct interest in the joint venture, and (2) an additional 1% interest in each of the two entities (each, a “Safeco Partner Entity”) through which each partner owns its interest in the joint venture.
[5] | The Company’s ownership includes (1) a 35.79% direct interest in the joint venture, (2) an additional 5.837% indirect ownership in the joint venture, and (3) an additional 1% interest in each of the two entities (each, a “360 Park Avenue South Partner Entity”) through which each partner owns its interest in the joint venture.
[6] | During the year ended December 31, 2020, the Company recognized an other-than-temporary impairment loss on its investment in the unconsolidated joint venture that owns Dock 72 in Brooklyn, New York totaling approximately $60.5 million.
[7] | During the year ended December 31, 2021, the Company completed the sale of its 50% ownership interest in Annapolis Junction NFM LLC. The Company recognized a gain on sale of investment of approximately $10.3 million.

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