INCOME TAXES - Schedule of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred income tax assets:
Deferred revenue	$ 38.0	$ 35.7
F&I chargeback liabilities	12.1	13.2
Other accrued liabilities	2.9	6.6
Stock-based compensation	3.7	3.1
Operating lease right-of-use assets	61.5	59.1
Other, net	12.9	9.4
Total deferred income tax assets	131.2	127.1
Deferred income tax liabilities:
Intangible asset amortization	110.8	91.0
Depreciation	56.9	52.1
Operating lease liabilities	59.9	57.5
Investments, net	20.0	24.0
Deferred sales commissions	18.3	0.0
Other, net	1.6	3.2
Total deferred income tax liabilities	267.6	227.8
Net deferred income tax liabilities	$ (136.4)	$ (100.7)