Inventories - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Interest credits and advertising assistance	$ 69.4	$ 49.1	$ 53.3

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