XML 35 R61.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2

Revenues - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Charge back reserve	$ 49.7	$ 46.4
Adjustment due to Topic 606 | Maintenance and Repair Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustments to retained earnings			$ 4.8
Adjustment due to Topic 606 | Vehicle Financing, Sale of Service and Insurance Contracts
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustments to retained earnings			$ 6.6

X

- Definition

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 27
-URI http://asc.fasb.org/extlink&oid=118944142&loc=SL49130611-203046-203046

+ Details

Name:	us-gaap_ContractWithCustomerRefundLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

+ References

No definition available.

+ Details

Name:	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

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

X

- Details

Name:	us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis=us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ProductOrServiceAxis=gpi_MaintenanceAndRepairMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ProductOrServiceAxis=us-gaap_FinancialServiceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: