ACCUMULATED OTHER COMPREHENSIVE LOSS - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				$ (614.8)
Other comprehensive income		$ (1.4)	$ (5.3)	(15.8)	[1]	$ (13.7)
Ending balance		(701.9)		(701.9)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(251.7)
Other comprehensive income	[1]			(15.8)
Ending balance		(235.9)		(235.9)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(24.0)
Other comprehensive income				(5.3)
Ending balance		(18.7)		(18.7)
Other comprehensive income (loss), tax benefit (expense)				(1.5)
Actuarial (Loss) Gain on Post-retirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(224.4)
Other comprehensive income				(8.7)
Ending balance		(215.7)		(215.7)
Actuarial (Loss) Gain on Post-retirement Benefits - Amortization of pension related costs
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income				(6.1)
Other comprehensive income (loss), tax benefit (expense)				(1.3)
Actuarial (Loss) Gain on Post-retirement Benefits - Net gain (loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income				(2.6)
Other comprehensive income (loss), tax benefit (expense)				(0.3)
Deferred Gain (Loss) - Hedging
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(3.0)
Ending balance		(1.2)		(1.2)
Deferred Gain (Loss) - Hedging - amortization of deferred gains (losses) related to the de-designated 2013 Interest Rate Swap
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income				1.8
Other comprehensive income (loss), tax benefit (expense)				1.1
Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(0.3)
Other comprehensive income				0.0
Ending balance		$ (0.3)		$ (0.3)

[1] See Note 13, “Accumulated Other Comprehensive Loss,” regarding the changes in the accumulated balances for each component of other comprehensive loss during the nine months ended September 30, 2017.