Inventories and Floor Plan Payables - Floor Plan Outstanding (Details) - Floor Plan Facility - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Floor Plan Payable
Total commitment	$ 1,700,000	$ 1,700,000
Less: borrowings, net	(899,568)	(1,011,345)
Less: flooring line aggregate interest reduction account	(218,575)	(92,108)
Additional borrowing capacity	581,857	596,547
Less: short-term payable for sold inventory	(40,011)	(28,036)
Less: purchase commitments	37,671	34,612
Unencumbered borrowing capacity	504,175	533,899
Line of Credit
Floor Plan Payable
Total commitment	70,000	70,000
Less: borrowings, net	(20,885)	(20,885)
Additional borrowing capacity	49,115	49,115
Letters of credit
Floor Plan Payable
Total commitment	30,000	30,000
Less: outstanding letters of credit	(11,371)	(11,500)
Additional letters of credit capacity	$ 18,629	$ 18,500