Segment Information - Financial Information By Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 796.0	$ 798.5	$ 713.3	$ 710.0	$ 755.2	$ 713.6	$ 799.5	$ 688.9	$ 3,017.8	[1]	$ 2,957.2	[1]	$ 2,965.1	[1]
Segment Income (Loss)									517.6		516.3		536.8
Identifiable assets	4,197.2				4,139.5				4,197.2		4,139.5		3,806.5
Capital expenditures									62.2		58.5		48.2
Depreciation									46.7		48.3		49.7
Consumer Solutions
Segment Reporting Information [Line Items]
Net sales									1,742.9		1,611.7		1,578.4
Segment Income (Loss)									419.1		379.6		392.9
Identifiable assets	2,327.9				2,329.9				2,327.9		2,329.9		1,952.2
Capital expenditures									27.4		31.2		22.7
Depreciation									21.4		21.8		20.9
Industrial & Flow Technologies
Segment Reporting Information [Line Items]
Net sales									1,273.6		1,344.1		1,385.4
Segment Income (Loss)									164.6		199.0		198.8
Identifiable assets	1,661.7				1,562.8				1,661.7		1,562.8		1,588.0
Capital expenditures									26.6		20.3		14.8
Depreciation									19.8		21.0		23.5
Corporate Segment
Segment Reporting Information [Line Items]
Net sales									1.3		1.4		1.3
Segment Income (Loss)									(66.1)		(62.3)		(54.9)
Identifiable assets	$ 207.6				$ 246.8				207.6		246.8		266.3
Capital expenditures									8.2		7.0		10.7
Depreciation									$ 5.5		$ 5.5		$ 5.3

[1] (1) One customer in the Consumer Solutions segment, Pool Corporation, represented approximately 15% of our consolidated net sales in 2020, 2019 and 2018.