Inventories and Floor Plan Payables - Floor Plan Outstanding (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jun. 30, 2023
Minimum
Floor Plan Payable
Floor plan payment due period	3 days	3 days	3 days
Maximum
Floor Plan Payable
Floor plan payment due period	10 days	10 days	10 days
Floor Plan Facility
Floor Plan Payable
Total commitment	$ 1,850,000	$ 1,700,000	$ 1,700,000	$ 1,700,000
Less: borrowings	(1,017,543)	(899,568)	(1,319,941)
Less: FLAIR offset account	(207,411)	(218,575)	(217,669)
Additional borrowing capacity	625,046	581,857	162,390
Less: short-term payable for sold inventory	(62,420)	(40,011)	(33,501)
Less: purchase commitments	(42,715)	(37,671)	(43,807)
Unencumbered borrowing capacity	519,911	504,175	85,082
Line of Credit | Floor Plan Facility
Floor Plan Payable
Total commitment	70,000	70,000	70,000
Less: borrowings	(20,885)	(20,885)	(20,885)
Additional borrowing capacity	49,115	49,115	49,115
Letters of credit | Floor Plan Facility
Floor Plan Payable
Total commitment	30,000	30,000	30,000
Less: outstanding letters of credit	(11,300)	(11,371)	(11,371)
Additional letters of credit capacity	$ 18,700	$ 18,629	$ 18,629