Information by Business Segment - Reconciliation of NOI from Real Estate Operations and NOI from Service Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment financial information for real estate operations
Depreciation and other amortization associated with real estate operations	$ (38,351)	$ (36,995)
General, administrative, leasing and other expenses	(11,747)	(10,490)
Interest expense	(20,767)	(16,442)
Interest and other income, net	4,122	2,256
Gain on sales of real estate	0	49,378
Equity in income (loss) of unconsolidated entities	69	(64)
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,740)	(1,642)
Income tax expense	(168)	(125)
Net income	33,671	80,398
Real Estate Operations
Segment financial information for real estate operations
NOI from real estate operations	101,657	93,903
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,740)	(1,642)
Service Operations
Segment financial information for real estate operations
NOI from service operations	$ 596	$ 619