Share-Based Compensation (Schedule Of Share-Based Compensation Information) (Parenthetical) (Details)	6 Months Ended
Jun. 30, 2016 USD ($)
Share Based Compensation [Abstract]
Expense reduction related to forfeiture of restricted shares	$ 267,000

Share-based compensation arrangement by share-based payment award, net of expense reduction related to forfeiture.

No definition available.

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