CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (Parenthetical) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013
CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS
Dealership acquisitions net, repayment of sellers' floor plan notes payable	$ 23.0	$ 1.8

Repayment of sellers' floor plan notes payable, dealership acquisitions.

No definition available.

Name:	pag_RepaymentOfSellersFloorPlanNotesPayableDealershipAcquisitions
Namespace Prefix:	pag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration