Inventories - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Inventory Disclosure [Abstract]
Interest credits and advertising assistance	$ 14.4	$ 13.3

Floor plan interest credits and advertising assistance received from vendors, which reduce the cost of sales.

No definition available.

Name:	pag_FloorPlanInterestCreditsAndAdvertisingAssistance
Namespace Prefix:	pag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration