INCOME TAXES - ADDITIONAL INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Excess tax benefit recorded during period	$ 2.2	$ 6.3
Tax expense from release of valuation allowance	1.2
Tax expense related to enacted statutory rate changes	0.2	12.2
Tax benefit for other discrete tax matters	(7.2)	$ 1.4
Tax expense related to U.S. tax reform	3.4
Tax expense related to gain on sale of marketable securities	1.1
Tax expense related to transition tax for accumulated foreign earnings, provisional liability	$ 1.0