Restructuring - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021 USD ($) Person	Mar. 31, 2020 USD ($)	Jun. 30, 2020 Person
Restructuring Cost and Reserve [Line Items]
Number of employees | Person	25		175
Total restructuring costs	$ 1.1	$ 2.7
Aquatic Systems
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	0.5	0.6
Filtration Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	0.5	0.9
Flow Technologies
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	$ 0.1	$ 1.2