Information by Business Segment (Details 4) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Reconciliation of segment assets to total assets
Total COPT consolidated assets	$ 3,803,469	$ 3,656,005	$ 3,612,362
Operating properties lease liabilities included in segment assets	16,640
Segment assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	3,036,140		3,042,452
Operating properties lease liabilities included in segment assets	16,502		0
Non-operating property assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	523,801		431,661
Other assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	$ 227,026		$ 138,249