Basis of Presentation and Summary of Significant Accounting Policies - Net Sales Information (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	[1]	$ 2,957.2	$ 2,965.1	$ 2,845.7
Residential
Disaggregation of Revenue [Line Items]
Net sales		1,668.2	1,665.9	1,579.0
Commercial
Disaggregation of Revenue [Line Items]
Net sales		627.3	630.7	604.4
Industrial
Disaggregation of Revenue [Line Items]
Net sales		661.7	668.5	662.3
U.S.
Disaggregation of Revenue [Line Items]
Net sales		1,866.7	1,858.1	1,752.7
Western Europe
Disaggregation of Revenue [Line Items]
Net sales		401.6	402.7	381.9
Developing
Disaggregation of Revenue [Line Items]
Net sales		480.6	476.5	478.2
Other Developed
Disaggregation of Revenue [Line Items]
Net sales		$ 208.3	$ 227.8	$ 232.9

[1] ⁽¹⁾  One customer in the Aquatic Systems segment, Pool Corporation, represented approximately 15% of our consolidated net sales in 2019, 2018 and 2017.