Consolidated Statements of Operations (USD $)
In Thousands, except Per Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Revenues    
Rental revenue $ 98,238 $ 98,035
Tenant recoveries and other real estate operations revenue 24,472 26,842
Construction contract and other service revenues 38,324 21,790
Total revenues 161,034 146,667
Expenses    
Property operating expenses 50,681 49,772
Depreciation and amortization associated with real estate operations 31,599 43,596
Construction contract and other service expenses 37,498 18,624
General, administrative and leasing expenses 7,891 8,143
Business development expenses and land carry costs 2,790 1,326
Total operating expenses 130,459 121,461
Operating income 30,575 25,206
Interest expense (20,838) (20,827)
Interest and other income 1,283 1,285
Loss on early extinguishment of debt (3) 0
Income from continuing operations before equity in income of unconsolidated entities and income taxes 11,017 5,664
Equity in income of unconsolidated entities 25 60
Income tax expense (55) (64)
Income from continuing operations 10,987 5,660
Discontinued operations (238) 11
Income before gain on sales of real estate 10,749 5,671
Gain on sales of real estate 3,986 0
Net income 14,735 5,671
Net income attributable to noncontrolling interests:    
Common units in COPLP (398) (16)
Preferred units in COPLP (165) (165)
Other consolidated entities (817) (749)
Net income attributable to COPT 13,355 4,741
Preferred share/unit dividends/distributions (3,552) (4,490)
Net income attributable to COPT common shareholders 9,803 251
Net income attributable to COPT:    
Income from continuing operations 13,581 4,728
Discontinued operations, net (226) 13
Net income attributable to COPT 13,355 4,741
Basic earnings per common share    
Income from continuing operations (in dollars per share/unit) $ 0.10 [1] $ 0.00 [1]
Discontinued operations (in dollars per share/unit) $ 0.00 [1] $ 0.00 [1]
Net income attributable to COPT common shareholders (in dollars per share/unit) $ 0.10 [1] $ 0.00 [1]
Diluted earnings per common share    
Income from continuing operations (in dollars per share/unit) $ 0.10 [1] $ 0.00 [1]
Discontinued operations (in dollars per share/unit) $ 0.00 [1] $ 0.00 [1]
Net income attributable to COPT common shareholders (in dollars per share/unit) $ 0.10 [1] $ 0.00 [1]
Dividends declared per common share/unit $ 0.275 $ 0.275
Corporate Office Properties, L.P.    
Revenues    
Rental revenue 98,238 98,035
Tenant recoveries and other real estate operations revenue 24,472 26,842
Construction contract and other service revenues 38,324 21,790
Total revenues 161,034 146,667
Expenses    
Property operating expenses 50,681 49,772
Depreciation and amortization associated with real estate operations 31,599 43,596
Construction contract and other service expenses 37,498 18,624
General, administrative and leasing expenses 7,891 8,143
Business development expenses and land carry costs 2,790 1,326
Total operating expenses 130,459 121,461
Operating income 30,575 25,206
Interest expense (20,838) (20,827)
Interest and other income 1,283 1,285
Loss on early extinguishment of debt (3) 0
Income from continuing operations before equity in income of unconsolidated entities and income taxes 11,017 5,664
Equity in income of unconsolidated entities 25 60
Income tax expense (55) (64)
Income from continuing operations 10,987 5,660
Discontinued operations (238) 11
Income before gain on sales of real estate 10,749 5,671
Gain on sales of real estate 3,986 0
Net income 14,735 5,671
Net income attributable to noncontrolling interests:    
Net income attributable to noncontrolling interests in consolidated entities (818) (737)
Net income attributable to COPT 13,917 4,934
Preferred share/unit dividends/distributions (3,717) (4,655)
Net income attributable to COPT common shareholders 10,200 279
Net income attributable to COPT:    
Income from continuing operations 14,152 4,921
Discontinued operations, net (235) 13
Net income attributable to COPT $ 13,917 $ 4,934
Basic earnings per common share    
Income from continuing operations (in dollars per share/unit) $ 0.10 [2] $ 0.00 [2]
Discontinued operations (in dollars per share/unit) $ 0.00 [2] $ 0.00 [2]
Net income attributable to COPT common shareholders (in dollars per share/unit) $ 0.10 [2] $ 0.00 [2]
Diluted earnings per common share    
Income from continuing operations (in dollars per share/unit) $ 0.10 [2] $ 0.00 [2]
Discontinued operations (in dollars per share/unit) $ 0.00 [2] $ 0.00 [2]
Net income attributable to COPT common shareholders (in dollars per share/unit) $ 0.10 [2] $ 0.00 [2]
Dividends declared per common share/unit $ 0.275 $ 0.275
[1] Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.
[2] Basic and diluted earnings per common unit are calculated based on amounts attributable to common unitholders of Corporate Office Properties, L.P.