Disposal Group Including Discontinued Operation Expenses

No definition available.

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

- Definition

Impairment charges reversals net.

+ References

No definition available.

+ Details

Name:	cdr_ImpairmentChargesReversalsNet
Namespace Prefix:	cdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Impairment Reversals Of Discontinued Operations

+ References

No definition available.

+ Details

Name:	cdr_ImpairmentReversalsOfDiscontinuedOperations
Namespace Prefix:	cdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax of income (loss) from operations classified as a discontinued operation. Excludes gain (loss) on disposal and provision for gain (loss) until disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721523-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=65878427&loc=d3e957-107759

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Revenue from the sale of commercial, industrial, or residential property during the period. This element is more likely than not relevant to an entity for which real estate operations are a principal activity. If real estate operations are not a principal activity, the reporting entity would likely use a gain (loss) on sale of property, plant, or equipment type element.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=cdr_HuntingdonPlazaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementOperatingActivitiesSegmentAxis=us-gaap_SegmentDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Real Estate (Narrative) (Details) - USD ($)		12 Months Ended
Real Estate (Narrative) (Details) - USD ($)	Feb. 02, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Impairment reversal				$ 153,000
Discontinued operations, income				12,000
Huntingdon Plaza [Member] \| Discontinued Operations [Member]
Real Estate Properties [Line Items]
Sales price of real estate sold	$ 2,200,000
Impairment reversal	$ 153,000
Discontinued operations, revenues				39,000
Discontinued operations, expenses				27,000
Discontinued operations, income				12,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate Properties [Line Items]
Impairment charges/(reversal), net		$ 9,500,000	$ 6,300,000	$ (200,000)