DISCONTINUED OPERATIONS AND OTHER DIVESTITURES - Assets and liabilities of discontinued operations (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Assets of discontinued operations — current	$ 100.3	$ 54.7
Assets of discontinued operations — non-current (1)	0.0	35.2
Liabilities of discontinued operations — current	49.9	31.3
Long-term liabilities classified as held for sale	0.0	15.7
Discontinued Operations | Brazil
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Cash and cash equivalents	3.7	18.3
Contracts-in-transit and vehicle receivables, net	2.3	0.6
Accounts and notes receivable, net	11.8	7.8
Inventories	37.2	21.5
Prepaid expenses	1.9	4.0
Assets of discontinued operations — current	56.9	52.3
Property and equipment, net	22.3	23.9
Operating lease assets	2.4	2.8
Other long-term assets	7.8	8.5
Assets of discontinued operations — non-current (1)	32.5	35.2
Total assets, before valuation allowance	89.5	87.5
Valuation allowance	(76.4)	0.0
Total assets, net of valuation allowance	13.0	87.5
Floorplan notes payable — credit facility and other	3.3	1.1
Floorplan notes payable — manufacturer affiliates	20.1	6.7
Current maturities of long-term debt	0.0	0.7
Current operating lease liabilities	2.5	1.6
Accounts payable	13.7	12.2
Accrued expenses and other current liabilities	8.7	9.0
Liabilities of discontinued operations — current	48.3	31.3
Long-term debt	0.0	14.1
Long-term operating lease liabilities	0.0	1.5
Long-term liabilities classified as held for sale	0.0	15.7
Total liabilities	48.3	47.0
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Assets of discontinued operations — current	100.3	54.7
Assets of discontinued operations — non-current (1)	0.0	35.2
Liabilities of discontinued operations — current	49.9	31.3
Long-term liabilities classified as held for sale	0.0	15.7
Held-for-sale | Prime Automotive Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Assets of discontinued operations — current	52.3	0.0
Liabilities of discontinued operations — current	1.6	0.0
Held-for-sale | Brazil
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Assets of discontinued operations — current	13.0	52.3
Assets of discontinued operations — non-current (1)	0.0	35.2
Liabilities of discontinued operations — current	48.3	31.3
Long-term liabilities classified as held for sale	0.0	15.7
Held-for-sale | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Assets of discontinued operations — current	34.9	2.4
Liabilities of discontinued operations — current	$ 0.0	$ 0.0