XML 54 R43.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Business Combinations - Activity (Details) - item | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
The Car People |  |
Business combinations |  |
Number of retail locations acquired | 4 |
CarSense |  |
Business combinations |  |
Number of retail locations acquired |  | 5
CarShop |  |
Business combinations |  |
Number of retail locations acquired |  | 5
Retail Automotive Dealership |  |
Business combinations |  |
Number of acquired franchises | 4 | 4

X
- 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

X
- Definition Represents the number of retail locations acquired. + References No definition available. + Details
Name: | pag_NumberOfRetailLocationsAcquired
Namespace Prefix: | pag_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=pag_CarPeopleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=pag_CarSenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=pag_CarShopMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=pag_RetailAutomotiveDealershipOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |