v3.25.2
Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) - USD ($)
$ in Thousands
 4 Months Ended 6 Months Ended
Jun. 27, 2025
Mar. 05, 2025
Jun. 30, 2025
Jun. 30, 2025
Jun. 30, 2024
Feb. 27, 2025
Dec. 31, 2024
Schedule of Equity Method Investments [Line Items]              
Other Liabilities     $ (416,838) $ (416,838)     $ (450,796)
Investments in unconsolidated joint ventures     1,161,036 1,161,036     1,093,583
Investments In Affiliates Subsidiaries Associates And Joint Ventures net [1]     1,112,904 1,112,904     1,060,074
Payments to Acquire Equity Method Investments       84,432 $ 60,461    
Unconsolidated Joint Ventures [Member]              
Schedule of Equity Method Investments [Line Items]              
Other Liabilities     $ (48,100) $ (48,100)     (33,500)
Square 407 Limited Partnership [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Market Square North      
Ownership Percentage     50.00% 50.00%      
Other Liabilities [1]     $ (23,685) $ (23,685)     (11,924)
WP Project Developer LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Wisconsin Place Land and Infrastructure      
Ownership Percentage [2]     33.33% 33.33%      
Investments in unconsolidated joint ventures [1]     $ 29,534 $ 29,534     29,775
500 North Capitol Venture LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       500 North Capitol Street, NW      
Ownership Percentage     30.00% 30.00%      
Other Liabilities [1]     $ (12,486) $ (12,486)     (11,696)
501 K Street LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       1001 6th Street      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 45,837 $ 45,837     45,903
Podium Developer LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       The Hub on Causeway - Podium      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 40,492 $ 40,492     42,310
Residential Tower Developer LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Hub50House      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 39,498 $ 39,498     42,493
Hotel Tower Developer LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       The Hub on Causeway - Hotel Air Rights      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 14,662 $ 14,662     14,271
Office Tower Developer LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       100 Causeway Street      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 55,852 $ 55,852     55,810
1265 Main Office JV LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       1265 Main Street      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 3,340 $ 3,340     3,476
BNY Tower Holdings LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Dock 72      
Ownership Percentage [3]     50.00% 50.00%      
Other Liabilities [1]     $ (11,961) $ (11,961)     (9,889)
CA-Colorado Center LLC[Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Colorado Center      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 70,222 $ 70,222     65,000
7750 Wisconsin Avenue LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       7750 Wisconsin Avenue      
Ownership Percentage     50.00% 50.00%   50.00%  
Investments in unconsolidated joint ventures [1]     $ 48,072 $ 48,072     48,423
BP-M 3HB Venture LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       3 Hudson Boulevard      
Ownership Percentage     25.00% 25.00%      
Investments in unconsolidated joint ventures [1]     $ 111,471 $ 111,471     112,771
Platform 16 Holdings LP [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Platform 16      
Ownership Percentage     55.00% 55.00%      
Investments in unconsolidated joint ventures [1]     $ 57,805 $ 57,805     56,265
Gateway Portfolio Holdings LLC [Member]              
Schedule of Equity Method Investments [Line Items]              
Properties       Gateway Commons      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 271,454 $ 271,454     272,000
Rosecrans-Sepulveda Partners 4, LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       Beach Cities Media Campus      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 27,068 $ 27,068     27,051
Safeco Plaza REIT LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       Safeco Plaza      
Ownership Percentage [4]     33.67% 33.67%      
Investments in unconsolidated joint ventures [1]     $ 43 $ 43     0
Safeco Plaza REIT LLC | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     33.00% 33.00%      
360 PAS Holdco LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       360 Park Avenue South      
Ownership Percentage [5]     71.11% 71.11%      
Investments in unconsolidated joint ventures [1]     $ 89,769 $ 89,769     74,592
360 PAS Holdco LLC | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     35.79% 35.79%      
PR II BXP Reston Gateway LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       Skymark - Reston Next Residential      
Ownership Percentage     20.00% 20.00%      
Investments in unconsolidated joint ventures [1]     $ 14,900 $ 14,900     14,844
751 Gateway Holdings LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       751 Gateway      
Ownership Percentage     49.00% 49.00%      
Investments in unconsolidated joint ventures [1]     $ 119,634 $ 119,634     99,701
200 Fifth Avenue JV LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       200 Fifth Avenue      
Ownership Percentage     26.69% 26.69%      
Investments in unconsolidated joint ventures [1]     $ 74,446 $ 74,446     70,673
ABXP Worldgate Investments LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       13100 and 13150 Worldgate Drive      
Ownership Percentage     50.00% 50.00%      
Investments in unconsolidated joint ventures [1]     $ 19,632 $ 19,632     $ 18,225
Entity Owning Land And Infrastructure Of Project [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     33.33% 33.33%      
Safeco Partner Entity One [Member] | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     1.00% 1.00%      
Safeco Partner Entity Two | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     1.00% 1.00%      
360 Park Avenue South Partners Entity | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     1.00% 1.00%      
360 PAS Holdco LLC (indirect ownership) | Company's Share [Member]              
Schedule of Equity Method Investments [Line Items]              
Ownership Percentage     35.02% 35.02%      
CAB 290 Coles Venture LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       290 Coles Street - Common Equity      
Ownership Percentage   19.46% 19.46% [6] 19.46% [6]      
Investments in unconsolidated joint ventures [1]     $ 19,625 $ 19,625      
Payments to Acquire Equity Method Investments   $ 20,000          
CAB 290 Coles Holdco LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       290 Coles Street - Preferred Equity      
Ownership Percentage [6],[7]     0.00% 0.00%      
Investments in unconsolidated joint ventures [1]     $ 1,615 $ 1,615      
Payments to Acquire Equity Method Investments     $ 1,600        
CAB 290 Coles Holdco LLC | Maximum [Member]              
Schedule of Equity Method Investments [Line Items]              
Payments to Acquire Equity Method Investments       $ 65,000      
Internal Rate of return on preferred equity       13.00%      
17 Hartwell Avenue JV LLC              
Schedule of Equity Method Investments [Line Items]              
Properties       17 Hartwell Avenue      
Ownership Percentage 20.00%   20.00% [6] 20.00% [6]      
Investments in unconsolidated joint ventures [1]     $ 6,065 $ 6,065      
17 Hartwell Avenue JV LLC | Joint Venture Partner [Member]              
Schedule of Equity Method Investments [Line Items]              
Payments to Acquire Equity Method Investments $ 23,000            
[1] Investments with deficit balances aggregating approximately $48.1 million and $33.5 million at June 30, 2025 and December 31, 2024, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets.
[2] The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.33% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project.
[3] This property includes net equity balances from the amenity joint venture.
[4] The Company’s ownership includes (1) a 33.0% direct interest in the joint venture, and (2) an additional 1.0% interest in each of the two entities 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 35.02% indirect ownership in the joint venture, and (3) an additional 1.0% interest in the entity through which the partner owns its interest in the joint venture.
[6] This entity is a VIE (See Note 2).
[7] The Company agreed to fund up to $65.0 million of the required capital through its preferred equity investment. The Company’s preferred equity investment will earn a 13.0% internal rate of return (“IRR”) and is to be redeemed, in full, upon the earlier of two years after stabilization of the property or March 5, 2030.