INCOME TAXES - UNRECOGNIZED TAX BENEFITS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at beginning of the period	$ 16.4	$ 15.1	$ 15.9
Changes in tax positions of prior years, net			(0.3)
Changes in tax positions of prior years, net	2.1	2.1
Reductions for lapse of statute of limitations	(0.2)	(0.8)	(0.5)
Balance at the end	18.3	16.4	$ 15.1
Unrecognized tax benefits that, if recognized, would impact the effective rate	18.3
Interest accrued related to unrecognized tax benefits	$ 0.1	$ 0.1