Segment Information - Summary of Net Sales, Operating Income (Loss), and Total Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total net sales	$ 334.7	$ 270.1	$ 613.5	$ 556.2
Total operating income	38.5	31.3	66.3	63.6
Interest expense	1.1	1.8	2.2	3.3
Other (income) expense, net	(0.3)	2.0	(0.8)	2.2
Income before income taxes	37.7	27.5	64.9	58.1
Total assets	1,289.4		1,289.4		$ 1,208.8
Continuing Operations
Segment Reporting Information [Line Items]
Total assets	1,289.2		1,289.2		1,208.6
Discontinued Operations
Segment Reporting Information [Line Items]
Total assets	0.2		0.2		0.2
Environmental Solutions
Segment Reporting Information [Line Items]
Total net sales	281.3	214.2	509.4	447.2
Total operating income	38.5	28.6	65.6	58.0
Environmental Solutions | Continuing Operations
Segment Reporting Information [Line Items]
Total assets	1,021.2		1,021.2		926.8
Safety and Security Systems
Segment Reporting Information [Line Items]
Total net sales	53.4	55.9	104.1	109.0
Total operating income	7.8	10.4	15.0	17.8
Safety and Security Systems | Continuing Operations
Segment Reporting Information [Line Items]
Total assets	221.2		221.2		225.5
Corporate And Eliminations
Segment Reporting Information [Line Items]
Total operating income	(7.8)	$ (7.7)	(14.3)	$ (12.2)
Corporate And Eliminations | Continuing Operations
Segment Reporting Information [Line Items]
Total assets	$ 46.8		$ 46.8		$ 56.3