Revenues (Narrative) (Details) $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($)
Revenues [Abstract]
Reduction of net income due to recording of revenue on cash basis and write off outstanding straight-line receivable	$ 0.1
Unpaid billed charges of rent and tenant reimbursements	0.5
Unrecorded revenue from tenants	$ 0.5

Reduction of net income due to recording of revenue on cash basis and write off outstanding straight-line receivable .

No definition available.

Name:	cdr_ReductionOfNetIncomeDueToRecordingOfRevenueOnCashBasisAndWriteOffOutstandingStraightLineReceivable
Namespace Prefix:	cdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration