PENSION AND POST-RETIREMENT BENEFITS - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Expected Net Periodic Benefit Cost In Current Fiscal Year			$ (2.4)
Net periodic benefit (income) costs:
Defined Benefit Plan, Net Periodic Benefit Cost	$ (0.7)	$ (1.3)	(1.3)	$ (2.6)	$ (5.4)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0.2	0.2	0.4	0.4
Net periodic benefit (income) costs:
Defined Benefit Plan, Interest Cost	7.1	7.6	14.3	15.1
Defined Benefit Plan, Expected Return on Plan Assets	(10.2)	(10.3)	(20.3)	(20.7)
Amortization of actuarial loss	2.1	1.0	4.1	2.2
Defined Benefit Plan Net Periodic Benefit Cost Before Portion Allocated To Affiliate	(0.8)	(1.5)	(1.5)	(3.0)
Defined Benefit Plan Net Periodic Benefit Cost Portion Allocated To Affiliate	(0.1)	0.0	(0.1)	0.0
Defined Benefit Plan, Net Periodic Benefit Cost	(0.9)	(1.5)	(1.6)	(3.0)
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0.0	0.0	0.0	0.0
Net periodic benefit (income) costs:
Defined Benefit Plan, Interest Cost	0.1	0.1	0.2	0.3
Defined Benefit Plan, Expected Return on Plan Assets	0.0	0.0	0.0	0.0
Amortization of actuarial loss	0.1	0.1	0.1	0.1
Defined Benefit Plan Net Periodic Benefit Cost Before Portion Allocated To Affiliate	0.2	0.2	0.3	0.4
Defined Benefit Plan Net Periodic Benefit Cost Portion Allocated To Affiliate	0.0	0.0	0.0	0.0
Defined Benefit Plan, Net Periodic Benefit Cost	$ 0.2	$ 0.2	$ 0.3	$ 0.4