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Investment in Unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 Months Ended | 4 Months Ended | 12 Months Ended |  |
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Dec. 31, 2022 USD ($) | Dec. 23, 2022 ft² loanExtension | Dec. 22, 2022 USD ($) loanExtension | Dec. 07, 2022 ft² | Dec. 06, 2022 USD ($) loanExtension | Nov. 17, 2022 USD ($) ft² floor | Sep. 09, 2022 USD ($) ft² | Sep. 08, 2022 USD ($) | Sep. 01, 2022 USD ($) ft² | Aug. 08, 2022 USD ($) ft² | Aug. 07, 2022 USD ($) | Jun. 17, 2022 USD ($) | Jun. 16, 2022 USD ($) ft² | May 13, 2022 USD ($) loanExtension years | Apr. 18, 2022 USD ($) ft² | Mar. 28, 2022 USD ($) years loanExtension | Mar. 27, 2022 USD ($) years loanExtension | Dec. 31, 2022 USD ($) | Sep. 06, 2023 | Sep. 05, 2023 | Apr. 30, 2023 | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Feb. 02, 2022 ft² | Jan. 18, 2022 ft²
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  | $ 3,272,368 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 3,272,368 |  |  |  | $ 3,272,368 |  | $ 3,267,914 |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 0.775% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payment for Debt Extinguishment or Debt Prepayment Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 43,036 | $ 0 |  |  |
Losses from early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  | (45,182) | 0 |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 277,581 |  | 98,152 | 172,436 |  |  |
Assumption of mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  | 200,311 | 0 |  |  |
Gateway Commons Complex [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [1] | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  | 50.00% |  |  |  |  |  |
Gateway Commons Complex [Member] | 651 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%
Platform 16 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [2] | 55.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55.00% |  |  |  | 55.00% |  |  |  |  |  |
Platform 16 | Platform 16 | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55.00% |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,100,000 |
BP/CRF Metropolitan Square LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  | 20.00% |  |  |  |  |  |
BP/CRF Metropolitan Square LLC [Member] | Metropolitan Square | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  | 657,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 420,000 | $ 294,100 |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | the greater of (x) LIBOR or (y) 0.65% |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.75% | 4.75% |  |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 | 2 |  |  |  |  |  |  |  |  |  |  |
Extension Option (in years) | years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 | 1 |  |  |  |  |  |  |  |  |  |  |
Payment for Debt Extinguishment or Debt Prepayment Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |  |  |  |  |
Losses from early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (1,300) |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,500 |  |  |  |  |  |  |  |  |  |  |  |
BP/CRF Metropolitan Square LLC [Member] | Metropolitan Square | Unconsolidated Properties | Interest Rate Cap |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  |  |  |  |  | SOFR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  |  |  |  |  |  |  |  |  | $ 420,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Cap Interest Rate |  |  |  |  |  |  |  |  |  | 4.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Residential Tower Developer LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  | 50.00% |  |  |  |  |  |
Residential Tower Developer LLC [Member] | Hub50House [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  |  | $ 6,800 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Residential Tower Developer LLC [Member] | Hub50House [Member] | Unconsolidated Properties | Interest Rate Swap |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 185,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Forward Interest Rate |  |  |  |  |  |  |  |  |  |  |  |  | 4.432% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Residential Tower Developer LLC [Member] | Hub50House [Member] | Unconsolidated Properties | Adjustable Rate Loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  |  |  |  |  |  |  |  |  |  | $ 185,000 | $ 176,700 |  | $ 176,500 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  | 1.35% |  |  | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |
PR II BXP Reston Gateway LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [3] | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  | 20.00% |  |  |  |  |  |
751 Gateway Holdings LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [1] | 49.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 49.00% |  |  |  | 49.00% |  |  |  |  |  |
BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [4] | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  | 50.00% |  |  |  |  |  |
BNY Tower Holdings LLC [Member] | Dock 72 [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  | 669,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  | $ 198,400 |  |  |  |  |  |  | $ 198,400 | $ 198,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  | the greater of (x) SOFR or (y) 0.25% |  |  |  |  |  |  | the greater of (x) SOFR or (y) 0.25% | LIBOR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  | 2.50% |  |  |  |  |  |  | 3.10% | 3.35% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 0.25% |  |  |  |  |  |  | 0.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, borrowing capacity |  |  |  |  |  |  |  |  |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment loss on investment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 50,700 |  |  |  |  |  |  |  |  |  |
Capitalization Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.75% |  |  |  |  |  |  |  |  |  |
Investment in Unconsolidated Joint Venture, Measurement Input |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7.00% |  |  |  |  |  |  |  |  |  |
Equity Method Investment, impairment information |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | The Company determined that its valuation of the investment was categorized within Level 3 of the fair value hierarchy, as it utilized significant unobservable inputs in its assessment including an exit capitalization rate of 5.75%, a discount rate on the Company’s equity investment (the property is encumbered by mortgage debt) of 7.0% and leasing the currently available space over the period of 2023-2026. |  |  |  |  |  |  |  |  |  |
Safeco Plaza REIT LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage | [5] | 33.67% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 33.67% |  |  |  | 33.67% |  |  |  |  |  |
Safeco Plaza REIT LLC | Safeco Plaza | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  | 33.67% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  | 765,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  |  |  |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  |  |  | the greater of (x) 2.35% or (y) SOFR | the greater of (x) 2.35% or (y) LIBOR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  | 2.32% | 2.20% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Safeco Plaza REIT LLC | Safeco Plaza | Unconsolidated Properties | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  | 2.35% | 2.35% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Safeco Plaza REIT LLC | Safeco Plaza | Unconsolidated Properties | Interest Rate Cap |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  |  |  | SOFR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  |  |  |  |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Cap Interest Rate |  |  |  |  |  |  |  | 2.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
200 Fifth Avenue JV LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 26.69% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 26.69% |  |  |  | 26.69% |  |  |  |  |  |
200 Fifth Avenue JV LLC | 200 Fifth Avenue | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  | 26.69% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  | 855,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  | 1.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Noncash or Part Noncash Acquisition, Value of Assets Acquired |  |  |  |  |  |  | $ 280,200 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  | 120,100 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Assumption of mortgage notes payable |  |  |  |  |  |  | $ 160,100 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of floors | floor |  |  |  |  |  |  | 14 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
200 Fifth Avenue JV LLC | 200 Fifth Avenue | Unconsolidated Properties | Interest Rate Swap |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  |  |  |  |  |  | $ 600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Forward Interest Rate |  |  |  |  |  |  | 4.34% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Square 407 Limited Partnership [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  | 50.00% |  |  |  |  |  |
Square 407 Limited Partnership [Member] | Market Square North | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  | 418,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  |  |  | $ 125,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  | the greater of (1) the sum of (x) the “benchmark rate”, (y) 2.30% and (z) the adjustment applicable to such “benchmark rate” (approximately 0.11% for Term SOFR), or (2) 2.80% | the greater of (x) LIBOR or (y) 0.50%, |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Extension Option (in years) |  |  |  |  | 1 | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Square 407 Limited Partnership [Member] | Market Square North | Unconsolidated Properties | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 2.80% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Podium Developer LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  | 50.00% |  |  |  |  |  |
Joint Venture Partner [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Interest in Joint Venture |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 500 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Joint Venture Partner [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties | Scenario, Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 80.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Interest in Joint Venture |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 58,700 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Joint Venture Partner [Member] | 751 Gateway Holdings LLC | 751 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 51.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contribution of Property |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 53,900 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Interest in Joint Venture |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,900 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  | $ 4,022,746 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,022,746 |  |  |  | $ 4,022,746 |  | 3,214,961 |  |  |  |
Losses from early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (1,327) |  | 0 | 0 |  |  |
Impairment loss on investment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (50,705) | [6] | $ 0 | $ (60,524) | [6] |  |
Unconsolidated Joint Ventures [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contribution of Property |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 11,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties | Scenario, Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Interest in Joint Venture |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 3,500 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties | Adjustable Rate Loans |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  |  |  |  |  |  |  |  |  |  | SOFR |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Extension Option (in years) | years |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Unused Borrowing Capacity, Amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 140,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | 751 Gateway Holdings LLC | 751 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 49.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contribution of Property |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 53,900 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Interest in Joint Venture |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Podium Developer LLC [Member] | The Hub on Causeway - Podium | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  | 380,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  | $ 174,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Podium Developer LLC [Member] | The Hub on Causeway - Podium | Unconsolidated Properties | London Interbank Offered Rate (LIBOR) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  | 2.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.25% |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Podium Developer LLC [Member] | The Hub on Causeway - Podium | Unconsolidated Properties | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.35% |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Office Tower Developer LLC | 100 Causeway Street [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  | 630,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $3,272,368 and $3,267,914 at December 31, 2022 and December 31, 2021, respectively) |  |  |  | $ 337,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of extensions | loanExtension |  |  | 2 | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Extension Option (in years) |  |  | 1 | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Office Tower Developer LLC | 100 Causeway Street [Member] | Unconsolidated Properties | London Interbank Offered Rate (LIBOR) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  | 1.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.50% |  |  |  |  |  |  |
Unconsolidated Joint Ventures [Member] | Office Tower Developer LLC | 100 Causeway Street [Member] | Unconsolidated Properties | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.60% |  |  |  |  |  |  |  |
Company's Share [Member] | BP/CRF Metropolitan Square LLC [Member] | Metropolitan Square |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 20,100 |  |  |  |  |  |  |  |  |  |  |  |
Company's Share [Member] | Residential Tower Developer LLC [Member] | Hub50House [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  |  | $ 3,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Company's Share [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 96.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Company's Share [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties | Scenario, Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Construction | Gateway Commons Complex [Member] | 651 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 327,000
Construction | Platform 16 | Platform 16 | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 390,000 |
Construction | 751 Gateway Holdings LLC | 751 Gateway | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  | 231,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Construction | Unconsolidated Joint Ventures [Member] | PR II BXP Reston Gateway LLC | Reston Next Residential | Unconsolidated Properties | Scenario, Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Units in Real Estate Property |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 508 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Residential Building | Residential Tower Developer LLC [Member] | Hub50House [Member] | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 320,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Units in Real Estate Property |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 440 |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | On June 16, 2022, in accordance with the Gateway Commons joint venture agreement, 751 Gateway was segregated into a new single-purpose joint venture.
[2] | This entity is a VIE (See Note 2).
[3] | The Company’s partner will fund required capital until its aggregate investment is approximately 80% of all capital contributions; thereafter, the partners will fund required capital according to their percentage interests.
[4] | This property includes net equity balances from the amenity joint venture.
[5] | 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 through which each partner owns its interest in the joint venture.
[6] | During the years ended December 31, 2022 and 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 $50.7 million and $60.5 million, respectively.

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