ACCUMULATED OTHER COMPREHENSIVE LOSS - Reclassification out of Accumulated Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 1.4	$ 5.3	$ 15.8	[1]	$ 13.7
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(614.8)
Ending balance	(701.9)		(701.9)
Interest rate swap
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Ending balance	(1.2)		(1.2)
Deferred gain - hedging
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(3.0)
Ending balance	(1.2)		(1.2)
Deferred gain - hedging | Interest rate swap
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1.8)	(4.5)			(3.8)
Ending balance	(1.2)	(3.7)	(1.2)		(3.7)
Deferred gain - hedging | Interest rate swap | Reclassification out of Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Change in fair value, net of tax		0.1			(1.9)
Other Comprehensive Income (Loss), Tax [Abstract]
Change in fair value - tax expense (benefit)		0.1			1.1
Deferred gain - hedging | Interest rate swap | Interest Expense | Reclassification out of Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			1.8
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassifications into earnings, net of tax		0.7			2.0
Other Comprehensive Income (Loss), Tax [Abstract]
Reclassifications into earnings - tax expense (benefit)	0.4	$ 0.4	$ 1.1		$ (1.2)
Designated as Hedging Instrument [Member] | Deferred gain - hedging | Interest rate swap | Interest Expense | Reclassification out of Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassifications into earnings, net of tax	$ 0.6

[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.