ACQUISITIONS AND DIVESTITURES - Schedule of LMH Acquisition, Purchase Consideration (Details) - USD ($) $ in Millions	Dec. 17, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill		$ 1,783.4	$ 2,271.7	$ 562.2
Total liabilities assumed		$ 21.3	$ 16.2
LHM Acquisition
Business Acquisition [Line Items]
Cash, net of cash acquired	$ 195.0
Common stock offering	666.9
Payable to sellers	6.0
Purchase price, net of cash acquired	3,193.9
Cash and cash equivalents	287.4
Investments	133.5
Contracts-in-transit, net	99.5
Accounts receivable, net	110.0
Inventories, net	282.1
Other current assets	25.0
Total current assets	937.5
Property and equipment, net	805.6
Goodwill	1,205.3
Intangible franchise rights	1,309.7
Operating lease right-of-use assets	34.1
Deferred income taxes	139.7
Other long-term assets	5.6
Total assets acquired	4,437.6
Accounts payable and accrued liabilities	229.5
Operating lease liabilities	34.1
Deferred revenue	667.6
Other long-term liabilities	25.2
Total liabilities assumed	956.4
Net assets acquired	3,481.2
LHM Acquisition | Senior Notes
Business Acquisition [Line Items]
Purchase price holdbacks	1,378.5
LHM Acquisition | Revolving Credit Facility
Business Acquisition [Line Items]
Purchase price holdbacks	200.0
LHM Acquisition | 2021 Real Estate Facility
Business Acquisition [Line Items]
Purchase price holdbacks	513.0
LHM Acquisition | New Vehicle Floor Plan Facility
Business Acquisition [Line Items]
Purchase price holdbacks	183.5
LHM Acquisition | Used Vehicle Floor Plan Facility
Business Acquisition [Line Items]
Purchase price holdbacks	$ 51.0