COPT Defense Properties Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Narrative (Details)

v3.23.3

Fair Value Measurements - Narrative (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($) land_parcel property	Dec. 31, 2019
Assets and liabilities measured at fair value on a recurring and nonrecurring basis
Number of impaired parcels of land \| land_parcel	1
Other segment
Assets and liabilities measured at fair value on a recurring and nonrecurring basis
Number of impaired operating real estate properties \| property	6
Impairment losses	$ 252,800
Real estate, fair value disclosure	311,300
Fair value measurement on a recurring basis
Assets and liabilities measured at fair value on a recurring and nonrecurring basis
Marketable securities in deferred compensation plan	1,748
Fair value measurement on a recurring basis \| Deferred compensation plan \| Trustees and Management
Assets and liabilities measured at fair value on a recurring and nonrecurring basis
Maximum percentage of participants' compensation which is deferrable		100.00%
Marketable securities in deferred compensation plan	$ 1,700

- Definition

Represents the maximum percentage of participants' compensation that is deferrable by participants under the deferred compensation plan.

+ References

No definition available.

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- Definition

Number Of Impaired Operating Real Estate Properties

+ References

No definition available.

+ Details

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- Definition

Number Of Impaired Parcels Of Land

+ References

No definition available.

+ Details

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- Definition

Real Estate, Fair Value Disclosure

+ References

No definition available.

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- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-3

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- Definition

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

+ 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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482099/360-10-50-2

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