Restructuring and Transformation Programs - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Person	Sep. 30, 2020 USD ($)	Dec. 31, 2020 Person
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	$ 4.0	$ 1.8	$ 11.2	$ 5.6
Number of employees | Person			50		175
Aquatic Systems
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	0.1	0.4	$ 0.8	2.4
Filtration Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	(0.2)	1.1	0.3	1.7
Flow Technologies
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	$ 4.1	$ 0.3	$ 10.1	$ 1.5