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Investments in Unconsolidated Joint Ventures (Tables) | 9 Months Ended
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Sep. 30, 2025
Schedule of Equity Method Investments [Line Items] |
Investments In Unconsolidated Joint Ventures | The investments in unconsolidated joint ventures consist of the following at September 30, 2025 and December 31, 2024:
|  |  |  |  |  | Carrying Value of Investment (1)
Entity |  | Properties |  | Nominal % Ownership |  | September 30, 2025 |  | December 31, 2024
|  |  |  |  |  | (in thousands)
Square 407 Limited Partnership |  | Market Square North |  | 50.00 | % |  | $ | (23,691) |  |  | $ | (11,924) |
WP Project Developer LLC |  | Wisconsin Place Land and Infrastructure |  | 33.33 | % | (2) | 29,209 |  |  | 29,775 |
500 North Capitol Venture LLC |  | 500 North Capitol Street, NW |  | 30.00 | % |  | (12,435) |  |  | (11,696) |
501 K Street LLC |  | 1001 6th Street |  | 50.00 | % |  | 45,772 |  |  | 45,903 |
Podium Venture LLC |  | The Hub on Causeway - Podium |  | 50.00 | % | (3) | 55,231 |  |  | 42,310 |
Residential Tower Developer LLC |  | Hub50House |  | 50.00 | % |  | 33,654 |  |  | 42,493 |
Hotel Tower Developer LLC |  | The Hub on Causeway - Hotel Air Rights |  | 50.00 | % |  | 11,849 |  |  | 14,271 |
Office Venture LLC |  | 100 Causeway Street |  | 50.00 | % | (3) | 48,833 |  |  | 55,810 |
1265 Main Office JV LLC |  | 1265 Main Street |  | 50.00 | % |  | 3,217 |  |  | 3,476 |
BNY Tower Holdings LLC |  | Dock 72 |  | 50.00 | % | (4) | (14,326) |  |  | (9,889) |
CA-Colorado Center, LLC |  | Colorado Center |  | 50.00 | % |  | 69,015 |  |  | 65,000 |
7750 Wisconsin Avenue LLC |  | 7750 Wisconsin Avenue |  | 50.00 | % |  | 47,363 |  |  | 48,423 |
BP-M 3HB Venture LLC |  | 3 Hudson Boulevard |  | 25.00 | % |  | 110,581 |  |  | 112,771 |
Platform 16 Holdings LP |  | Platform 16 |  | 55.00 | % |  | 58,076 |  |  | 56,265 |
Gateway Portfolio Holdings LLC |  | Gateway Commons |  | 50.00 | % | (5) | 125,090 |  |  | 272,000 |
Rosecrans-Sepulveda Partners 4, LLC |  | Beach Cities Media Campus |  | 50.00 | % | (6) | 98 |  |  | 27,051 |
Safeco Plaza REIT LLC |  | Safeco Plaza |  | 33.67 | % | (7) | 121 |  |  | — |
360 PAS Holdco LLC |  | 360 Park Avenue South |  | 71.11 | % | (8) | 93,988 |  |  | 74,592 |
PR II/BXP Reston Gateway LLC |  | Skymark - Reston Next Residential |  | 20.00 | % |  | 14,702 |  |  | 14,844 |
751 Gateway Holdings LLC |  | 751 Gateway |  | 49.00 | % |  | 118,509 |  |  | 99,701 |
200 Fifth Avenue JV LLC |  | 200 Fifth Avenue |  | 26.69 | % |  | 75,376 |  |  | 70,673 |
ABXP Worldgate Investments LLC |  | 13100 and 13150 Worldgate Drive |  | 50.00 | % |  | 19,855 |  |  | 18,225 |
CAB 290 Coles Venture LLC |  | 290 Coles Street - Common Equity |  | 19.46 | % | (9) | 19,813 |  |  | N/A
CAB 290 Coles Holdco LLC |  | 290 Coles Street - Preferred Equity |  | — | % | (9)(10) | 12,014 |  |  | N/A
17 Hartwell Avenue JV LLC |  | 17 Hartwell Avenue |  | 20.00 | % | (9) | 7,398 |  |  | N/A
|  |  |  |  |  | $ | 949,312 |  |  | $ | 1,060,074 |
_______________ (1)Investments with deficit balances aggregating approximately $50.5 million and $33.5 million at September 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)In conjunction with the execution of the mortgage loan signed on September 30, 2025 (described below), Podium Venture LLC and Office Venture LLC were created for structuring purposes and did not change any of the partner rights previously held by the partners of Podium Developer LLC or Office Tower Developer LLC, respectively. (4)This investment includes net equity balances from the amenity joint venture. (5)During the three months ended September 30, 2025, the Company recognized an other-than-temporary impairment loss on its investment. (6)On September 17, 2025, the joint venture completed the sale of Beach Cities Media Campus, a land parcel, located in El Segundo, California. (7)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. (8)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. (9)This entity is a VIE (See Note 2). (10)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 and accrue 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.
Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block] | The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows:
| September 30, 2025 |  | December 31, 2024
| (in thousands)
ASSETS |  |  |
Real estate and development in process, net (1) | $ | 5,781,519 |  |  | $ | 5,748,198 |
Other assets (2) | 708,615 |  |  | 703,096 |
Total assets | $ | 6,490,134 |  |  | $ | 6,451,294 |
LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY |  |  |
Mortgage and notes payable, net | $ | 3,186,295 |  |  | $ | 3,206,723 |
Other liabilities (3) | 252,689 |  |  | 292,125 |
Members’/Partners’ equity | 3,051,150 |  |  | 2,952,446 |
Total liabilities and members’/partners’ equity | $ | 6,490,134 |  |  | $ | 6,451,294 |
Company’s share of equity | $ | 1,365,565 |  |  | $ | 1,344,543 |
Basis differentials (4) | (416,253) |  |  | (284,469) |
Carrying value of the Company’s investments in unconsolidated joint ventures (5) | $ | 949,312 |  |  | $ | 1,060,074 |
_______________ (1)At September 30, 2025 and December 31, 2024, this amount included right of use assets - operating leases totaling approximately $18.1 million and $19.0 million, respectively. (2)At September 30, 2025 and December 31, 2024, this amount included sales-type lease receivable, net totaling approximately $14.3 million and $14.1 million, respectively. (3)At September 30, 2025 and December 31, 2024, this amount included lease liabilities - operating leases totaling approximately $30.5 million. (4)This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. During the thee months ended September 30, 2025, the Company recognized an other-than-temporary impairment loss on its investment in Gateway Commons of approximately $145.1 million. During the year ended December 31, 2024, the Company recognized an other-than-temporary impairment loss on its investments in Colorado Center, Gateway Commons and Safeco Plaza of approximately $168.4 million, $126.1 million, and $46.8 million, respectively. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. The Company’s basis differences include:
| September 30, 2025 |  | December 31, 2024
Property | (in thousands)
Colorado Center | $ | 130,440 |  |  | $ | 127,632 |
200 Fifth Avenue | 48,864 |  |  | 49,656 |
Gateway Commons | (216,170) |  |  | (74,500) |
Safeco Plaza | (73,275) |  |  | (75,576) |
Dock 72 | (89,347) |  |  | (92,054) |
360 Park Avenue South | (111,025) |  |  | (113,265) |
Platform 16 | (142,666) |  |  | (142,698) |
Other basis differentials | 36,926 |  |  | 36,336 |
Total basis differentials | $ | (416,253) |  |  | $ | (284,469) |
These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities. (5)Investments with deficit balances aggregating approximately $50.5 million and $33.5 million at September 30, 2025 and December 31, 2024, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
Statements Of Operations Of The Joint Ventures | The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows:
| Three months ended September 30, |  | Nine months ended September 30,
| 2025 |  | 2024 |  | 2025 |  | 2024 |  |
| (in thousands)
Total revenue (1) | $ | 128,190 |  |  | $ | 128,435 |  |  | $ | 384,309 |  |  | $ | 378,981 |  |  |
Expenses |  |  |  |  |  |  |  |  |
Operating | 56,578 |  |  | 53,280 |  |  | 165,497 |  |  | 148,929 |  |  |
Transaction costs | 2 |  |  | 53 |  |  | 173 |  |  | 61 |  |  |
Depreciation and amortization | 45,409 |  |  | 41,082 |  |  | 131,940 |  |  | 118,901 |  |  |
Total expenses | 101,989 |  |  | 94,415 |  |  | 297,610 |  |  | 267,891 |  |  |
Other income (expense) |  |  |  |  |  |  |  |  |
Loss from early extinguishment of debt | — |  |  | — |  |  | (62) |  |  | — |  |  |
Interest expense | (47,202) |  |  | (45,244) |  |  | (136,738) |  |  | (132,106) |  |  |
Unrealized loss on derivative instruments | (1,403) |  |  | (19,172) |  |  | (14,632) |  |  | (8,212) |  |  |
Gain on sale of real estate (2) | 4,762 |  |  | — |  |  | 4,762 |  |  | — |  |  |
Net loss | $ | (17,642) |  |  | $ | (30,396) |  |  | $ | (59,971) |  |  | $ | (29,228) |  |  |
Company’s share of net loss (2) | $ | (6,613) |  |  | $ | (9,319) |  |  | $ | (20,099) |  |  | $ | (9,105) |  |  |
Gain on sale / consolidation (3) | — |  |  | — |  |  | — |  |  | 21,696 |  |  |
Impairment loss on investment (4) | (145,133) |  |  | — |  |  | (145,133) |  |  | — |  |  |
Basis differential (2)(5) | 3,417 |  |  | 2,308 |  |  | 11,440 |  |  | (6,215) |  |  |
Income (loss) from unconsolidated joint ventures | $ | (148,329) |  |  | $ | (7,011) |  |  | $ | (153,792) |  |  | $ | 6,376 |  |  |
_______________ (1)Includes straight-line rent adjustments of approximately $3.7 million and $2.6 million for the three months ended September 30, 2025 and 2024, respectively, and approximately $12.4 million and $16.5 million for the nine months ended September 30, 2025 and 2024, respectively. (2)During the three and nine months ended September 30, 2025, the joint venture recorded a gain on sale of real estate related to the Beach Cities Media Campus. As a result of the historical basis difference, the Company recognized a gain on sale of real estate totaling approximately $2.2 million, which consists of its share of the gain on sale reported by the joint venture as well as an adjustment for a basis differential. (3)During the nine months ended September 30, 2024, the Company acquired its joint venture partner’s 50% economic interest in 901 New York Avenue. (4)During the three and nine months ended September 30, 2025, the Company recognized an other-than-temporary impairment loss on its investment in Gateway Commons of approximately $145.1 million. (5)Includes depreciation and amortization of approximately $(3.1) million and $3.9 million for the three months ended September 30, 2025 and 2024, respectively, and approximately $(7.4) million and $6.8 million for the nine months ended September 30, 2025 and 2024, respectively. Includes unrealized losses on derivative instruments of approximately $0.4 million and $5.1 million for the three months ended September 30, 2025 and 2024, respectively, and approximately $3.9 million and $4.9 million for the nine months ended September 30, 2025 and 2024, respectively.

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