BASIS OF PRESENTATION - Tax (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
BASIS OF PRESENTATION
Effective tax rate (as a percent)	16.20%	19.20%	41.50%	20.30%
Income tax expenses benefit from release of capital loss valuation allowance	$ 0.5		$ 0.5
Provision for the intercompany sale of assets			0.7
Increase (net) in unrecognized tax benefits recognized discretely			$ 0.5