INCOME TAXES - Activities Related to Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 17.6	$ 17.0	$ 18.0
Increase in balance related to tax positions taken during current year	0.3	0.3	0.2
Decrease in balance as a result of a lapse of the applicable statutes of limitations	(0.2)	0.0	(0.1)
Increase in balance related to tax positions taken during prior years	0.0	0.3	0.0
Decrease in balance related to tax positions taken during prior years	(3.9)	0.0	(1.1)
Balance at end of period	$ 13.8	$ 17.6	$ 17.0