COMMITMENTS AND CONTINGENCIES (Narrative) (Details) $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2017 USD ($)	Aug. 31, 2014 Claims	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Rental expense			$ 42.5	$ 36.8	$ 30.9
Sublease rental income			2.6	2.0	$ 1.4
Expected future sublease rental income	$ 6.5		$ 6.5
Number of lawsuits filed | Claims		2
Payroll tax audit liability				$ 0.5
Payments of tax settlements	$ 0.7