Leases - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) parcel property	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Leases [Abstract]
Number of properties subject to operating lease | property	5
Operating lease, weighted average remaining term	71 years
Number of properties subject to finance lease | property	1
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:RentalProperties us-gaap:DevelopmentInProcess cuz:LandHeld
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	cuz:LandHeld
Finance lease, weighted average remaining term	5 years
Operating ground leases, right-of-use asset	$ 55,800,000
Finance ground leases, right-of-use asset	3,700,000
Operating ground leases, liability	58,619,000	$ 59,379,000
Finance ground leases, liability	$ 3,555,000	$ 9,730,000
Finance Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Operating lease, weighted average discount rate	4.50%
Finance lease, weighted average discount rate	4.50%
Operating lease expense	$ 4,300,000	$ 3,900,000
Operating lease expense			$ 3,500,000
Variable lease expense	0
Interest expense related to finance lease	474,000
Operating lease payments	$ 3,500,000
Number of parcels of land purchased | parcel	1
Land purchased	$ 6,400,000