INCOME TAXES - (Benefit) Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Current federal	$ 17.0	$ 12.5	$ 2.6
Current state	3.3	2.1	2.4
Current foreign	0.1	0.1	0.0
Total current	20.4	14.7	5.0
Deferred:
Deferred federal	(0.8)	1.1	7.7
Deferred state	0.3	0.3	0.6
Deferred foreign	0.0	0.0	0.1
Total deferred	(0.5)	1.4	8.4
Income tax	$ 19.9	$ 16.1	$ 13.4