INCOME TAXES - Tax Effects of Temporary Differences Representing Deferred Tax Assets/Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Loss reserves and accruals	$ 53.5	$ 50.4
Interest rate swaps	0.0	10.0
U.S. state NOL carryforwards	30.8	34.5
Operating lease liabilities	79.5	55.8
Other	2.8	2.2
Deferred tax assets	166.6	152.9
Less: valuation allowance on deferred tax assets	24.2	30.9
Net deferred tax assets	142.4	122.0
Deferred tax liabilities:
Goodwill and intangible franchise rights	152.2	142.0
Depreciation expense	99.4	71.1
Interest rate swaps	0.6	0.0
Operating lease ROU assets	63.5	44.0
Other	1.7	2.0
Deferred tax liabilities	317.4	259.1
Net deferred tax liability	$ 175.0	$ 137.1