ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 137.6	$ 131.6
Less—Allowance for doubtful accounts	(1.4)	(1.3)
Accounts receivable, net	136.2	130.3
Vehicle receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	44.8	45.7
Manufacturer receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	50.4	51.2
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 42.4	$ 34.7