EMPLOYEE BENEFIT PLANS - Summary of Amounts Recognized on the Consolidated Balance Sheets and in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Amounts recognized on the consolidated balance sheets [Abstract]
Non-current liabilities	$ (64.8)	$ (59.7)
Pension Benefits
Amounts recognized on the consolidated balance sheets [Abstract]
Current liabilities	0.0	0.0
Non-current liabilities	(53.9)	(48.4)
Total	(53.9)	(48.4)
Amounts recognized in accumulated other comprehensive loss [Abstract]
Net loss (net of taxes)	45.6	47.3
Unrecognized prior service credit (net of taxes)	(1.8)	(2.6)
Total	43.8	44.7
Other Post-retirement Benefits
Amounts recognized on the consolidated balance sheets [Abstract]
Current liabilities	(1.0)	(0.9)
Non-current liabilities	(10.9)	(11.3)
Total	(11.9)	(12.2)
Amounts recognized in accumulated other comprehensive loss [Abstract]
Net loss (net of taxes)	0.6	0.6
Unrecognized prior service credit (net of taxes)	0.0	0.0
Total	$ 0.6	$ 0.6