Annual report pursuant to Section 13 and 15(d)

Information by Business Segment (Details 2)

v3.10.0.1
Information by Business Segment (Details 2) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Reconciliation of segment revenues to total revenues                      
Construction contract and other service revenues                 $ 60,859 $ 102,840 $ 48,364
Total revenues $ 138,482 $ 137,411 $ 146,743 $ 155,476 $ 164,567 $ 157,017 $ 151,435 $ 139,801 578,112 612,820 574,328
Reconciliation of Operatiing Income from Unconsolidated Joint Ventures to Equity Method Investments [Abstract]                      
UJV NOI allocable to COPT                 4,818 4,805 2,145
Less: Income from UJV allocable to COPT attributable to depreciation and amortization expense and interest expense                 (3,314) (3,310) (1,413)
Add: Equity in income (loss) of unconsolidated non-real estate entities                 1,193 (5) 20
Equity in income of unconsolidated entities                 2,697 1,490 752
Computation of net operating income from service operations                      
Construction contract and other service revenues                 60,859 102,840 48,364
Construction contract and other service expenses                 (58,326) (99,618) (45,481)
Real estate operations [Member]                      
Reconciliation of segment revenues to total revenues                      
Total revenues                 517,253 509,980 525,964
Reconciliation of Operatiing Income from Unconsolidated Joint Ventures to Equity Method Investments [Abstract]                      
UJV NOI allocable to COPT                 4,818 4,805 2,145
Service operations [Member]                      
Computation of net operating income from service operations                      
NOI from service operations                 $ 2,533 $ 3,222 $ 2,883