Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details 3)

v3.10.0.1
Summary of Significant Accounting Policies (Details 3) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture $ 40,806 $ 42,752 $ 40,806 $ 42,752 $ 41,787 $ 43,661
Cumulative distributions in excess of net income (822,270) (777,049) (822,270) (777,049) (802,085) (747,825)
Noncontrolling interests in subsidiaries 66,280 67,339 66,280 67,339 66,165 72,267
Common units 1,033   1,033   1,013  
Equity in income of unconsolidated entities 373 370 746 747    
Income before gain on sales of real estate 21,108 18,847 39,892 37,349    
Net income 21,085 18,859 39,865 41,599    
Net income attributable to noncontrolling interests - Common units in COPLP (608) (261) (1,152) (883)    
Net income attributable to COPT/COPLP 19,434 17,526 36,584 38,545    
Net income attributable to COPT/COPLP common share/unit holders 19,434 7,640 36,584 25,479    
Comprehensive income 22,950 18,039 46,651 42,187    
Comprehensive income attributable to COPT/ COPLP 21,242 16,733 43,153 39,113    
Corporate Office Properties, L.P.            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture 40,806 42,752 40,806 42,752 41,787 43,661
Noncontrolling interests in subsidiaries 12,875   12,875   12,312  
Common units 1,477,575 1,416,995 1,477,575 1,416,995 1,445,022 1,419,710
Equity in income of unconsolidated entities 373 370 746 747    
Income before gain on sales of real estate 21,108 18,847 39,892 37,349    
Net income 21,085 18,859 39,865 41,599    
Net income attributable to COPT/COPLP 20,207 17,952 38,066 39,758    
Net income attributable to COPT/COPLP common share/unit holders 20,042 7,901 37,736 26,362    
Comprehensive income 22,950 18,039 46,651 42,187    
Comprehensive income attributable to COPT/ COPLP $ 22,072 17,132 $ 44,852 40,346    
As Previously Reported            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture   25,335   25,335 25,066 25,548
Cumulative distributions in excess of net income   (793,828)   (793,828) (818,190) (765,276)
Noncontrolling interests in subsidiaries   66,701   66,701 65,549 71,605
Equity in income of unconsolidated entities   718   1,443    
Income before gain on sales of real estate   19,195   38,045    
Net income   19,207   42,295    
Net income attributable to noncontrolling interests - Common units in COPLP   (273)   (907)    
Net income attributable to COPT/COPLP   17,862   39,217    
Net income attributable to COPT/COPLP common share/unit holders   7,976   26,151    
Comprehensive income   18,387   42,883    
Comprehensive income attributable to COPT/ COPLP   17,069   39,785    
As Previously Reported | Corporate Office Properties, L.P.            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture   25,335   25,335 25,066 25,548
Common units   1,399,578   1,399,578 1,428,301 1,401,597
Equity in income of unconsolidated entities   718   1,443    
Income before gain on sales of real estate   19,195   38,045    
Net income   19,207   42,295    
Net income attributable to COPT/COPLP   18,300   40,454    
Net income attributable to COPT/COPLP common share/unit holders   8,249   27,058    
Comprehensive income   18,387   42,883    
Comprehensive income attributable to COPT/ COPLP   17,480   41,042    
Accounting Standards Update 2017-05            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture   17,417   17,417 16,721 18,113
Cumulative distributions in excess of net income   16,779   16,779 16,105 17,451
Noncontrolling interests in subsidiaries   638   638 616 662
Equity in income of unconsolidated entities   (348)   (696)    
Income before gain on sales of real estate   (348)   (696)    
Net income   (348)   (696)    
Net income attributable to noncontrolling interests - Common units in COPLP   12   24    
Net income attributable to COPT/COPLP   (336)   (672)    
Net income attributable to COPT/COPLP common share/unit holders   (336)   (672)    
Comprehensive income   (348)   (696)    
Comprehensive income attributable to COPT/ COPLP   (336)   (672)    
Accounting Standards Update 2017-05 | Corporate Office Properties, L.P.            
New Accounting Pronouncements or Change in Accounting Principle [Line Items]            
Investment in unconsolidated real estate joint venture   17,417   17,417 16,721 18,113
Common units   17,417   17,417 $ 16,721 $ 18,113
Equity in income of unconsolidated entities   (348)   (696)    
Income before gain on sales of real estate   (348)   (696)    
Net income   (348)   (696)    
Net income attributable to COPT/COPLP   (348)   (696)    
Net income attributable to COPT/COPLP common share/unit holders   (348)   (696)    
Comprehensive income   (348)   (696)    
Comprehensive income attributable to COPT/ COPLP   $ (348)   $ (696)