Leases - Lessee Arrangements (Details) $ in Millions	Sep. 30, 2023 USD ($)
Leases [Abstract]
Carrying value of lessee right-of-use asset	$ 43.1

Amount of lessee's right to use underlying asset under operating and finance leases.

No definition available.

Name:	ofc_LesseeRightOfUseAssetCarryingValue
Namespace Prefix:	ofc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant