Information by Business Segment (Details 4) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of segment assets to total assets
Total COPT consolidated assets	$ 3,854,453	$ 3,656,005
Operating properties lease liabilities included in segment assets	17,317
Segment assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	3,024,958	3,084,862
Operating properties lease liabilities included in segment assets	17,317	0
Non-operating property assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	621,630	410,671
Other assets
Reconciliation of segment assets to total assets
Total COPT consolidated assets	$ 190,548	$ 160,472