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

Income Taxes (Details) (Taxable REIT Subsidiary, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Taxable REIT Subsidiary
Deferred income tax (expense) benefit
Federal	$ (83)	$ (20)	$ (215)	$ (50)
State	(18)	(4)	(42)	(11)
Total income tax expense	$ (101)	$ (24)	$ (257)	$ (61)
Effective tax rate (as a percent)	37.70%	36.70%	37.70%	36.70%

Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.