Restructuring and Other - Schedule of Changes in the Restructuring Reserve (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost And Reserve [Line Items]
Balance at the beginning			$ 23.5
Restructuring Charges	$ 9.0	$ 3.5	13.8	$ 11.5
Foreign Exchange and Other			(0.4)
Cash Paid			(14.0)
Balance at the end	22.9		22.9
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning			9.6
Restructuring Charges			8.4
Foreign Exchange and Other			(0.4)
Cash Paid			(8.7)
Balance at the end	8.9		8.9
Multi-employer pension plan withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning			11.0
Restructuring Charges			0.3
Cash Paid			(0.7)
Balance at the end	10.6		10.6
Lease terminations and other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning			2.9
Restructuring Charges			5.1
Cash Paid			(4.6)
Balance at the end	$ 3.4		$ 3.4