Restructuring, Impairment and Other Charges - Schedule of Changes in the Restructuring Reserve (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 21.0	$ 21.1
Restructuring Charges	28.3	25.4	$ 31.6
Foreign Exchange and Other	1.1	(3.7)
Cash Paid	(26.9)	(21.8)
Balance at the end	23.5	21.0	21.1
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	7.6	6.1
Restructuring Charges	23.5	21.9
Foreign Exchange and Other	0.1	(3.6)
Cash Paid	(21.6)	(16.8)
Balance at the end	9.6	7.6	6.1
Multi-employer pension plan withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	11.8	12.7
Restructuring Charges	0.7	0.7
Cash Paid	(1.5)	(1.6)
Balance at the end	11.0	11.8	12.7
Lease terminations and other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	1.6	2.3
Restructuring Charges	4.1	2.8
Foreign Exchange and Other	1.0	(0.1)
Cash Paid	(3.8)	(3.4)
Balance at the end	$ 2.9	$ 1.6	$ 2.3