FLOORPLAN NOTES PAYABLE - Schedule of Floorplan Notes Payable (Details) - Line of Credit - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Revolving Credit Facility — floorplan notes payable
Line of Credit Facility
Long-term debt, gross	$ 1,022.3	$ 833.5
Long-term debt, offset	(191.7)	(140.2)
Long-term debt	830.6	693.3
Other non-manufacturer facilities
Line of Credit Facility
Long-term debt	58.4	68.8
Floorplan notes payable — credit facility and other, net
Line of Credit Facility
Long-term debt	889.0	762.1
FMCC Facility
Line of Credit Facility
Long-term debt, gross	95.4	55.1
Long-term debt, offset	(19.0)	(13.4)
Long-term debt	76.4	41.8
Other manufacturer affiliate facilities
Line of Credit Facility
Long-term debt	276.9	201.3
Floorplan notes payable — manufacturer affiliates, net
Line of Credit Facility
Long-term debt	$ 353.3	$ 243.1