INCOME TAXES - Components of the Company's provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0.6	$ (0.3)	$ (0.1)
State	(1.7)	3.7	4.0
Foreign	0.8
Total current taxes	(0.3)	3.4	3.9
Deferred:
Federal	0.1	(45.5)	(10.9)
State	(0.5)	(11.6)	(7.4)
Foreign	0.5	(0.9)	(1.5)
Total deferred taxes	0.1	(58.0)	(19.8)
Benefit for income taxes	$ (0.2)	$ (54.6)	$ (15.9)