Asset impairment charge on disposition

No definition available.

Name:	gpi_Assetimpairmentchargeondisposition
Namespace Prefix:	gpi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net Gain (Loss) on Real Estate and Dealership Transactions

+ References

No definition available.

+ Details

Name:	gpi_NetGainLossonRealEstateandDealershipTransactions
Namespace Prefix:	gpi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of Dealerships Disposed

+ References

No definition available.

+ Details

Name:	gpi_NumberofDealershipsDisposed
Namespace Prefix:	gpi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=51824106&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16373-109275

+ Details

Name:	us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	gpi_TaxeffectedAxis=gpi_PretaxMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	gpi_TaxeffectedAxis=gpi_NetoftaxesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=country_GB
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=country_BR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Selected Quarterly Financial Data (Unaudited) (Details Textual) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS	$ 20,000	$ 10,900	$ 1,000	$ 900	$ 85,700	$ 900	$ 1,000	$ 32,838	$ 87,562	$ 41,520
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 19,200	$ 10,600		$ 200	$ 85,500			30,000	30,100	31,000
Net Gain (Loss) on Real Estate and Dealership Transactions								2,200	8,200
Asset impairment charge on disposition								600
U.S.
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS								21,794	$ 18,983	15,570
Number of Dealerships Disposed									2
Net Gain (Loss) on Real Estate and Dealership Transactions								2,700	$ 9,400
U.S. \| Pre-tax [Member]
Condensed Financial Statements, Captions [Line Items]
Net Gain (Loss) on Real Estate and Dealership Transactions								2,700	8,900	13,800
U.S. \| Net of taxes [Member]
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS								13,500	12,000
Net Gain (Loss) on Real Estate and Dealership Transactions								1,700	5,500
U.K.
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS								201	330	0
Net Gain (Loss) on Real Estate and Dealership Transactions								(300)
Brazil
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS								10,843	68,249	$ 25,950
Net Gain (Loss) on Real Estate and Dealership Transactions								(800)
Brazil \| Pre-tax [Member]
Condensed Financial Statements, Captions [Line Items]
Net Gain (Loss) on Real Estate and Dealership Transactions								(800)
Brazil \| Net of taxes [Member]
Condensed Financial Statements, Captions [Line Items]
ASSET IMPAIRMENTS								$ 6,900	$ 62,400