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- Definition

Area of land held.

+ References

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
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-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-5

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
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-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

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The charge against earnings in the period to reduce the carrying amount of real property to fair value.

+ References

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Net rentable area for properties owned.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Real Estate (Narrative) (Details) $ in Thousands		12 Months Ended
Real Estate (Narrative) (Details) $ in Thousands	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