INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	10.60%	(35.40%)	(2.30%)	(35.20%)
Provisional income tax expense, Tax Cuts and Jobs Act of 2017			$ 1.5		$ 5.5
Excess tax benefit from share-based compensation		$ 4.1		$ 4.0
Income tax expense, to be paid within one year, Tax Cuts and Jobs Act of 2017					0.4
Tax benefit, re-measurement of net deferred tax liabilities, Tax Cuts and Jobs Act of 2017					$ 43.4