Segment Information - Total Assets, Equity Method Investments, and Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information
Capital expenditures	$ 79.1	$ 80.9	$ 226.5	$ 282.6
Retail Automotive
Segment Reporting Information
Capital expenditures	63.1	68.2	172.6	243.1
Retail Commercial Truck
Segment Reporting Information
Capital expenditures	14.0	10.7	49.3	33.3
Other
Segment Reporting Information
Capital expenditures	2.0	2.0	4.6	6.2
Non-Automotive Investments
Segment Reporting Information
Capital expenditures	$ 0.0	$ 0.0	$ 0.0	$ 0.0