Annual report pursuant to Section 13 and 15(d)

Information by Business Segment (Details 3)

v3.6.0.2
Information by Business Segment (Details 3) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Reconciliation of segment assets to total assets      
Total COPT consolidated assets $ 3,780,885 $ 3,909,312  
Segment assets [Member]      
Reconciliation of segment assets to total assets      
Total COPT consolidated assets 3,004,247 3,265,469 $ 2,951,495
Non-operating property assets [Member]      
Reconciliation of segment assets to total assets      
Total COPT consolidated assets 418,171 450,679  
Other assets [Member]      
Reconciliation of segment assets to total assets      
Total COPT consolidated assets $ 358,467 $ 193,164