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

Interest Rate Derivatives - Effect of Interest Rate Derivatives on Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income Recognized in AOCI on Derivatives	$ 2,042	$ 1,101	$ 6,816	$ 4,646
Amount of Income (Loss) Reclassified from AOCI into Interest Expense on Statement of Operations	1,146	77	2,711	(1,680)
Interest rate swaps
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income Recognized in AOCI on Derivatives	2,042	1,101	6,816	4,646
Interest rate swaps \| Interest expense
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income (Loss) Reclassified from AOCI into Interest Expense on Statement of Operations	$ 1,146	$ 77	$ 2,711	$ (1,680)