CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS
Repayment of Sellers' Floor Plan Notes Payable Dealership Acquisitions	$ 41.2	$ 22.4

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