Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Rental revenue	$ 101,347	$ 107,524	$ 201,962	$ 212,906
Tenant recoveries and other real estate operations revenue	26,950	26,400	53,102	54,105
Construction contract and other service revenues	23,138	12,003	36,172	23,223
Total revenues	151,435	145,927	291,236	290,234
Expenses
Property operating expenses	48,628	48,141	97,147	100,016
Depreciation and amortization associated with real estate operations	32,793	33,248	65,852	67,775
Construction contract and other service expenses	22,315	11,478	34,801	22,172
Impairment losses	1,625	69,692	1,625	72,138
General, administrative and leasing expenses	7,859	8,026	16,470	19,909
Business development expenses and land carry costs	1,597	2,363	3,290	4,781
Total operating expenses	114,817	172,948	219,185	286,791
Operating income (loss)	36,618	(27,021)	72,051	3,443
Interest expense	(19,163)	(22,639)	(38,157)	(46,198)
Interest and other income	1,583	1,330	3,309	2,486
(Loss) gain on early extinguishment of debt	(513)	5	(513)	22
Income (loss) before equity in income of unconsolidated entities and income taxes	18,525	(48,325)	36,690	(40,247)
Equity in income of unconsolidated entities	718	10	1,443	20
Income tax (expense) benefit	(48)	(1)	(88)	7
Income (loss) before gain on sales of real estate	19,195	(48,316)	38,045	(40,220)
Gain on sales of real estate	12	0	4,250	0
Net income (loss)	19,207	(48,316)	42,295	(40,220)
Net (income) loss attributable to noncontrolling interests:
Common units in COPLP	(273)	1,976	(907)	1,849
Preferred units in COPLP	(165)	(165)	(330)	(330)
Other consolidated entities	(907)	(914)	(1,841)	(1,892)
Net income (loss) attributable to COPT	17,862	(47,419)	39,217	(40,593)
Preferred share/unit dividends/distributions	(3,039)	(3,553)	(6,219)	(7,105)
Issuance costs associated with redeemed preferred shares	(6,847)	0	(6,847)	0
Net income (loss) attributable to COPT common shareholders	$ 7,976	$ (50,972)	$ 26,151	$ (47,698)
Earnings per common share:
Net income (loss) attributable to COPT common shareholders - basic (in dollars per share/unit)	$ 0.08	$ (0.54)	$ 0.26	$ (0.51)
Net income (loss) attributable to COPT common shareholders - diluted (in dollars per share/unit)	0.08	(0.54)	0.26	(0.51)
Dividends declared per common share/unit (in dollars per share)	$ 0.2750	$ 0.275	$ 0.55	$ 0.55
Corporate Office Properties, L.P.
Revenues
Rental revenue	$ 101,347	$ 107,524	$ 201,962	$ 212,906
Tenant recoveries and other real estate operations revenue	26,950	26,400	53,102	54,105
Construction contract and other service revenues	23,138	12,003	36,172	23,223
Total revenues	151,435	145,927	291,236	290,234
Expenses
Property operating expenses	48,628	48,141	97,147	100,016
Depreciation and amortization associated with real estate operations	32,793	33,248	65,852	67,775
Construction contract and other service expenses	22,315	11,478	34,801	22,172
Impairment losses	1,625	69,692	1,625	72,138
General, administrative and leasing expenses	7,859	8,026	16,470	19,909
Business development expenses and land carry costs	1,597	2,363	3,290	4,781
Total operating expenses	114,817	172,948	219,185	286,791
Operating income (loss)	36,618	(27,021)	72,051	3,443
Interest expense	(19,163)	(22,639)	(38,157)	(46,198)
Interest and other income	1,583	1,330	3,309	2,486
(Loss) gain on early extinguishment of debt	(513)	5	(513)	22
Income (loss) before equity in income of unconsolidated entities and income taxes	18,525	(48,325)	36,690	(40,247)
Equity in income of unconsolidated entities	718	10	1,443	20
Income tax (expense) benefit	(48)	(1)	(88)	7
Income (loss) before gain on sales of real estate	19,195	(48,316)	38,045	(40,220)
Gain on sales of real estate	12	0	4,250	0
Net income (loss)	19,207	(48,316)	42,295	(40,220)
Net (income) loss attributable to noncontrolling interests:
Net income attributable to noncontrolling interests in consolidated entities	(907)	(911)	(1,841)	(1,890)
Net income (loss) attributable to COPT	18,300	(49,227)	40,454	(42,110)
Preferred share/unit dividends/distributions	(3,204)	(3,718)	(6,549)	(7,435)
Issuance costs associated with redeemed preferred shares	(6,847)	0	(6,847)	0
Net income (loss) attributable to COPT common shareholders	$ 8,249	$ (52,945)	$ 27,058	$ (49,545)
Earnings per common share:
Net income (loss) attributable to COPT common shareholders - basic (in dollars per share/unit)	$ 0.08	$ (0.54)	$ 0.26	$ (0.51)
Net income (loss) attributable to COPT common shareholders - diluted (in dollars per share/unit)	0.08	(0.54)	0.26	(0.51)
Dividends declared per common share/unit (in dollars per share)	$ 0.275	$ 0.275	$ 0.55	$ 0.55