INCOME TAXES - (Benefit) Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current federal	$ 2.6	$ 0.7	$ 0.1
Current state	2.4	1.1	1.2
Current foreign	0.0	0.1	0.2
Total current	5.0	1.9	1.5
Deferred federal	7.7	(18.3)	0.0
Deferred state	0.6	(3.6)	1.1
Deferred foreign	0.1	0.0	0.0
Total deferred	8.4	(21.9)	1.1
Income tax	$ 13.4	$ (20.0)	$ 2.6