Summary of Significant Accounting Policies (Details 2)	12 Months Ended
Dec. 31, 2019 form
Share-Based Compensation
Number of forms of share based compensation plans	4
Corporate Office Properties, L.P
Noncontrolling Interest [Abstract]
Interests in several real estate entities owned directly by COPT	1.00%

Percentage of ownership in noncontrolling interests generally not exceeded by Parent.

No definition available.

Name:	ofc_NoncontrollingInterestPercentageGenerallyOwnedbyParent
Namespace Prefix:	ofc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant