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v3.25.4

Real Estate (Narrative) (Details) $ in Thousands |  | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 15, 2025 USD ($) ft² a | Dec. 31, 2025 USD ($) ft² | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) | Jul. 31, 2025 ft² floor | Jul. 17, 2025 ft² | Jul. 01, 2025 ft² | Jan. 16, 2025 ft²
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Acquisitions of real estate |  | $ 55,864 | $ 35,366 | $ 0 |  |  |  |
Gains on sales of real estate |  | 176,732 | 602 | 517 |  |  |  |
Impairment loss |  | 85,803 | 13,615 | 0 |  |  |  |
Boston Properties Limited Partnership |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Acquisitions of real estate |  | 55,864 | 35,366 | 0 |  |  |  |
Gains on sales of real estate |  | 179,322 | 602 | 517 |  |  |  |
Impairment loss |  | 82,890 | 13,615 | 0 |  |  |  |
Wholly Owned Properties |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Gains on sales of real estate |  | 176,700 | 600 | 500 |  |  |  |
Impairment loss |  | 85,800 | 13,600 |  |  |  |  |
Wholly Owned Properties | Boston Properties Limited Partnership |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Gains on sales of real estate |  | 179,300 | 600 | $ 500 |  |  |  |
Impairment loss |  | $ 82,900 | $ 13,600 |  |  |  |  |
Office Building [Member] |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  | 409,200 |  |  |  |  |  |
Gains on sales of real estate |  | $ 7,306 |  |  |  |  |  |
Office Building [Member] | Boston Properties Limited Partnership |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Gains on sales of real estate |  | $ 9,796 |  |  |  |  |  |
Reston Next Retail |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  |  | 30,000
1050 Winter Street |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  |  | 162,000 |
Reston Next Office Phase II |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  |  | 87,000 |  |
343 Madison Avenue |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  | 930,000 |  |  |
Number of floors | floor |  |  |  |  | 46 |  |  |
2100 M Street |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Acquisitions of real estate | $ 55,900 |  |  |  |  |  |  |
Area of Land | a | 1.0 |  |  |  |  |  |  |
2100 M Street | Office Building [Member] |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² | 320,000 |  |  |  |  |  |  |
2100 M Street | Retail Site [Member] |  |  |  |  |  |  |  |
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |
Net Rentable Area (in sf) | ft² | 10,000 |  |  |  |  |  |  |

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