Restructuring and Other - Multi-Employer Pension Plan Charges - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Restructuring Cost And Reserve [Line Items]
Multi-employer pension plan charges	$ 0.6	$ 0.6	$ 1.2	$ 1.2
Accrued liabilities	378.7		378.7		$ 447.5
Other noncurrent liabilities	207.8		207.8		$ 180.2
Multi-employer pension plan withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Accrued liabilities	5.1		5.1
Other noncurrent liabilities	$ 30.3		$ 30.3