INCOME TAXES - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Uncertain tax benefits, beginning balance	$ 2.7	$ 2.7	$ 2.7
Additions for tax positions related to current year	0.0	0.0	0.0
Additions for tax positions related to prior year	0.0	0.0	0.0
Reductions for tax positions related to prior years	0.0	0.0	0.0
Lapse of statute of limitations	0.0	0.0	0.0
Settlements	0.0	0.0	0.0
Uncertain tax benefits, ending balance	$ 2.7	$ 2.7	$ 2.7