Information by Business Segment - Reconciliation of UJV NOI to Equity in Income (Loss) of Unconsolidated Entities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconciliation of UJV NOI allocable to COPT to equity income (loss) in unconsolidated entities
UJV NOI allocable to COPT Defense	$ 1,740	$ 1,642
Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense	(1,671)	(1,704)
Add: Equity in loss of unconsolidated non-real estate entities	0	(2)
Equity in income (loss) of unconsolidated entities	$ 69	$ (64)