The percentage of investment ownership.

No definition available.

Name:	pag_InvestmentOwnershipPercentage
Namespace Prefix:	pag_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the ownership interest acquired by the entity during the period.

+ References

No definition available.

+ Details

Name:	pag_InvestmentOwnershipPercentageAcquired
Namespace Prefix:	pag_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum number of dealership locations wherein the vehicles were distributed and sold.

+ References

No definition available.

+ Details

Name:	pag_MinimumNumberOfDealershipLocations
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of franchises acquired.

+ References

No definition available.

+ Details

Name:	pag_NumberOfFranchisesAcquired
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of brands represented by franchises awarded to the reporting entity.

+ References

No definition available.

+ Details

Name:	pag_NumberOfFranchisesAwardedToReportingEntity
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of franchises disposed of during the period.

+ References

No definition available.

+ Details

Name:	pag_NumberOfFranchisesDisposedOf
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of full service retail locations acquired.

+ References

No definition available.

+ Details

Name:	pag_NumberOfFullServiceRetailLocationsAcquired
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of full service retail locations operated by the equity method investee.

+ References

No definition available.

+ Details

Name:	pag_NumberOfFullServiceRetailLocationsOperated
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of operating franchises.

+ References

No definition available.

+ Details

Name:	pag_NumberOfOperatingFranchises
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Total number of owned and operated franchises.

+ References

No definition available.

+ Details

Name:	pag_NumberOfOwnedAndOperatedFranchises
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of owned and operated franchises in domestic country.

+ References

No definition available.

+ Details

Name:	pag_NumberOfOwnedAndOperatedFranchisesInDomesticCountry
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of owned and operated franchises in foreign countries.

+ References

No definition available.

+ Details

Name:	pag_NumberOfOwnedAndOperatedFranchisesInForeignCountries
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of truck retail dealerships owned by the reporting entity.

+ References

No definition available.

+ Details

Name:	pag_NumberOfTruckRetailDealershipsOwnedByReportingEntity
Namespace Prefix:	pag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the total amount of receivables from manufacturers as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	pag_ReceivablesFromManufacturer
Namespace Prefix:	pag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	pag_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix:	pag_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ 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)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Definition

The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611443-123010

+ Details

Name:	us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=pag_GermanAutomotiveDealershipJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_PartnershipInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_RetailAutomotiveDealershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_RetailCommercialTruckDealershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=pag_PremierTruckGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_CommercialVehicleDistributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_BmwMiniMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_AudiVolkswagenPorscheBentleyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_ToyotaLexusScionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FranchisorDisclosureAxis=pag_MercedesBenzSprinterSmartMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	pag_TypesOfRevenueAxis=pag_RetailAutomotiveDealershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	pag_TypesOfRevenueAxis=pag_RetailCommercialTruckDealershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	pag_TypesOfRevenueAxis=pag_CommercialVehiclesDistributionAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Organization and Summary of Significant Accounting Policies (Details) $ in Millions		1 Months Ended		3 Months Ended								12 Months Ended
	Feb. 01, 2016 item	Sep. 30, 2015	Feb. 28, 2015 item	Dec. 31, 2015 USD ($) item	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Oct. 31, 2014
Organization and Summary of Significant Accounting Policies
Receivables from manufacturers \| $				$ 178.9				$ 172.0				$ 178.9	$ 172.0
Significant Accounting Policies
Total revenues \| $				$ 4,921.3	$ 4,960.1	$ 4,920.6	$ 4,482.9	$ 4,425.6	$ 4,396.7	$ 4,384.5	$ 4,025.2	$ 19,284.9	17,232.0	$ 14,482.5
German Automotive Dealership Group
Significant Accounting Policies
Number of acquired franchises												27
Ownership acquired (as a percentage)		10.00%										10.00%
Ownership interest (as a percent)				60.00%								60.00%
Penske Truck Leasing Co., L.P.
Significant Accounting Policies
Limited partnership interest (as a percent)												9.00%
Retail Automotive Dealership
Significant Accounting Policies
Total number of owned and operated franchises				355								355
Number of owned and operated franchises in US				181								181
Number of owned and operated franchises outside US				174								174
Number of acquired franchises												5
Number of franchises awarded to the reporting entity												1
Number of franchises disposed of												6
Retail Commercial Truck Dealership \| PTG
Significant Accounting Policies
Ownership acquired (as a percentage)												5.00%
Number of operating franchises	14
Ownership interest (as a percent)				96.00%								96.00%
Number of full service retail locations operated	10
Number of full service retail locations acquired			2
Ownership percentage of Equity Method Investment															32.00%
Commercial Vehicle Distribution
Significant Accounting Policies
Minimum number of dealership locations												70
Number of retail dealerships owned by the reporting entity												3
BMW/Mini \| Revenues
Significant Accounting Policies
Percentage of total												27.00%
Audi/Volkswagen/Porsche/Bentley \| Revenues
Significant Accounting Policies
Percentage of total												22.00%
Toyota/Lexus/Scion \| Revenues
Significant Accounting Policies
Percentage of total												15.00%
Mercedes-Benz/Sprinter/smart \| Revenues
Significant Accounting Policies
Percentage of total												10.00%
Retail Automotive Dealership
Significant Accounting Policies
Total revenues \| $												$ 17,896.3	16,657.5	14,329.9
Retail Commercial Truck Dealership
Significant Accounting Policies
Total revenues \| $												944.1	125.6
Commercial Vehicle Distribution and Other
Significant Accounting Policies
Total revenues \| $												$ 444.5	$ 448.9	$ 152.6