Segments - Geographic Information Additional (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	$ 1,260.3	$ 1,186.2	$ 1,155.2	$ 1,131.0	$ 1,227.8	$ 1,131.3	$ 1,070.3	$ 1,032.2	$ 4,732.7	$ 4,461.6	$ 4,211.3
Non-US
Entity Wide Information Revenue From External Customer [Line Items]
Maximum percentage of net sales in any one non-U.S. country	10.00%				10.00%				10.00%	10.00%	10.00%
Maximum percentage of long-lived assets in any one non-U.S. country	10.00%				10.00%				10.00%	10.00%	10.00%
U.S.program
Entity Wide Information Revenue From External Customer [Line Items]
Net sales									$ 2,402.8	$ 2,278.6	$ 2,112.1