INCOME TAXES - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Uncertain tax benefits, beginning balance	$ 2.7	$ 4.1
Additions for tax positions related to current year	0.0	0.0
Additions for tax positions related to prior year	0.0	0.0
Reductions for tax positions related to prior years	0.0	0.0
Lapse of statute of limitations	0.0	(0.3)
Change in statutory tax rate (1)	0.0	(1.1)
Settlements	0.0	0.0
Uncertain tax benefits, ending balance	$ 2.7	$ 2.7