Stockholders' Equity (Deficit), Accumulated Other Comprehensive Income (Loss) and Noncontrolling Interest - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Amortization of Defined Benefit Pension and Other Post-retirement Benefit Plan Items, Actuarial Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications out of AOCI	$ 1.9	$ 2.1	$ 3.8	$ 4.1
Foreign Currency Translation [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications out of AOCI	0.2		0.2
Net of tax	0.2		0.2
Amortization of Defined Benefit Pension and Other Post-retirement Benefit Plan Items, Prior Service Credits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications out of AOCI	(0.8)	(0.8)	(1.5)	(1.5)
Cash Flow Hedge - Interest Rate Swap [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net of tax			0.5
Realized swap interest loss	(0.3)	(0.1)	(0.6)	(0.1)
Tax provision			0.1
Net of tax	(0.3)	(0.1)	(0.5)	(0.1)
Amortization of Defined Benefit Pension and Other Post-retirement Benefit Plan Items [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications out of AOCI	1.1	1.3	2.3	2.6
Tax provision (benefit)	(0.3)	(0.4)	(0.6)	(0.7)
Net of tax	$ 0.8	$ 0.9	$ 1.7	$ 1.9