FLOOR PLAN NOTES PAYABLE - Schedule of Floor Plan Notes Payable (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Floor plan notes payable—trade (a)	$ 34.1	$ 39.3
Floor plan notes payable offset account	(14.0)	(2.0)
Floor plan notes payable—trade, net	20.1	37.3
Floor plan notes payable—non-trade	388.4	314.7
Floor plan notes payable—used non-trade	100.0	294.0
Floor plan notes payable offset account	(480.3)	(81.5)
Floor plan notes payable—non-trade, net	8.1	527.2
Floor plan notes payable—trade, liabilities associated with assets held for sale	2.0
Floor plan notes payable—non-trade, liabilities associated with assets held for sale	$ 18.8	$ 9.1