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Balance Type:	debit
Period Type:	instant

The amount of liabilities held-for-sale, not part of disposal group.

No definition available.

Name:	cigi_LiabilitiesHeldforsaleNotPartOfDisposalGroup
Namespace Prefix:	cigi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of liabilities held-for-sale, not part of disposal group,classified as current.

No definition available.

Name:	cigi_LiabilitiesHeldforsaleNotPartOfDisposalGroupCurrentTotal
Namespace Prefix:	cigi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of liabilities held-for-sale, not part of disposal group, classified as noncurrent.

No definition available.

Name:	cigi_LiabilitiesHeldforsaleNotPartOfDisposalGroupNoncurrentTotal
Namespace Prefix:	cigi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of assets held-for-sale that are not part of a disposal group.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=123398962&loc=d3e400-110220

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup
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Balance Type:	debit
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Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=123398962&loc=d3e400-110220

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(f))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910