Restructuring, Impairment and Other Charges - Other Charges - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Restructuring Cost And Reserve [Line Items]
Other Charges	$ 0.5	$ 0.6	$ 1.7	$ 1.7
Accrued liabilities	463.9		463.9		$ 541.7
Other noncurrent liabilities	175.8		175.8		$ 193.1
Multi-employer pension plan withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Other Charges	0.5	$ 0.6	1.7	$ 1.7
Accrued liabilities	5.1		5.1
Other noncurrent liabilities	$ 32.4		$ 32.4