Inventories and Floor Plan Payables - Floor Plan Outstanding (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Feb. 28, 2025	Dec. 31, 2024	Sep. 30, 2024
Minimum
Notes payable - floor plan:
Floor plan payment due period	3 days
Maximum
Notes payable - floor plan:
Floor plan payment due period	10 days
Floor Plan Facility
Notes payable - floor plan:
Total commitment	$ 2,150,000	$ 2,150,000	$ 1,850,000	$ 1,850,000
Less: borrowings	(1,361,019)		(1,161,713)	(1,030,187)
Less: FLAIR offset account	(277)		(79,472)	(151,539)
Additional borrowing capacity	788,704		608,815	668,274
Less: short-term payable for sold inventory	(60,188)		(33,152)	(65,015)
Less: purchase commitments	(43,471)		(9,340)	(30,432)
Unencumbered borrowing capacity	685,045		566,323	572,827
Line of Credit | Floor Plan Facility
Notes payable - floor plan:
Total commitment	70,000		70,000	70,000
Less: borrowings				(31,885)
Additional borrowing capacity	70,000		70,000	38,115
Letters of credit | Floor Plan Facility
Notes payable - floor plan:
Total commitment	45,000	$ 45,000	30,000	30,000
Less: outstanding letters of credit	(14,300)		(14,300)	(12,300)
Additional letters of credit capacity	$ 30,700		$ 15,700	$ 17,700