SUPPLEMENTAL GUARANTOR FINANCIAL INFORMATION (Statements of Comprehensive Income)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Guarantor Financial Information Statements Of Comprehensive Income [Line Items]
Net (loss) income	$ 17.5	$ 17.5	$ (1.0)	$ (37.9)	$ (62.7)	$ 5.9	$ 42.3	$ 13.1	$ (3.9)	$ (1.4)	$ 105.7
Foreign currency translation adjustments, net									(12.0)	(9.8)	(1.8)
Unrealized gains (losses) on derivative contracts, net									19.7	(2.7)	(5.1)
Pension and postretirement liability adjustments, net									(37.5)	(78.8)	(86.6)
Amortization of prior service costs and actuarial losses, net									12.3	41.9	15.5
Other comprehensive (loss) income									(17.5)	(49.4)	(78.0)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(21.4)	(50.8)	27.7
Parent Guarantor
Supplemental Guarantor Financial Information Statements Of Comprehensive Income [Line Items]
Net (loss) income									(3.9)	(1.4)	105.7
Foreign currency translation adjustments, net									0.0	0.0	0.0
Unrealized gains (losses) on derivative contracts, net									19.7	(2.7)	(5.1)
Pension and postretirement liability adjustments, net									(25.3)	(73.7)	(83.4)
Amortization of prior service costs and actuarial losses, net									10.9	39.6	14.1
Other comprehensive (loss) income									5.3	(36.8)	(74.4)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									1.4	(38.2)	31.3
Issuer
Supplemental Guarantor Financial Information Statements Of Comprehensive Income [Line Items]
Net (loss) income									42.7	(4.6)	0.0
Foreign currency translation adjustments, net									0.0	0.0	0.0
Unrealized gains (losses) on derivative contracts, net									0.0	0.0	0.0
Pension and postretirement liability adjustments, net									0.0	0.0	0.0
Amortization of prior service costs and actuarial losses, net									0.0	0.0	0.0
Other comprehensive (loss) income									0.0	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									42.7	(4.6)	0.0
Subsidiary Non-Guarantor
Supplemental Guarantor Financial Information Statements Of Comprehensive Income [Line Items]
Net (loss) income									112.5	114.5	48.8
Foreign currency translation adjustments, net									(12.0)	(9.8)	(1.8)
Unrealized gains (losses) on derivative contracts, net									0.0	0.0	0.0
Pension and postretirement liability adjustments, net									(12.2)	(5.1)	(3.2)
Amortization of prior service costs and actuarial losses, net									1.4	2.3	1.4
Other comprehensive (loss) income									(22.8)	(12.6)	(3.6)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									89.7	101.9	45.2
Eliminations
Supplemental Guarantor Financial Information Statements Of Comprehensive Income [Line Items]
Net (loss) income									(155.2)	(109.9)	(48.8)
Foreign currency translation adjustments, net									0.0	0.0	0.0
Unrealized gains (losses) on derivative contracts, net									0.0	0.0	0.0
Pension and postretirement liability adjustments, net									0.0	0.0	0.0
Amortization of prior service costs and actuarial losses, net									0.0	0.0	0.0
Other comprehensive (loss) income									0.0	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									$ (155.2)	$ (109.9)	$ (48.8)