Segment Information - Financial Information By Reportable Segment (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Identifiable assets	[1]	$ 6,868.8	$ 6,446.5	$ 6,563.3
Capital expenditures		68.8	74.4	76.0
Depreciation		59.6	60.3	59.5
Operating Segments
Segment Reporting Information [Line Items]
Identifiable assets		6,425.4	6,005.5	6,084.7
Capital expenditures		61.4	59.5	59.9
Depreciation		51.1	51.6	50.6
Corporate and other
Segment Reporting Information [Line Items]
Identifiable assets	[1]	443.4	441.0	478.6
Capital expenditures		7.4	14.9	16.1
Depreciation		8.5	8.7	8.9
Flow | Operating Segments
Segment Reporting Information [Line Items]
Identifiable assets	[1]	2,000.5	1,590.7	1,709.7
Capital expenditures		21.5	20.1	19.6
Depreciation		21.0	21.4	21.1
Water Solutions | Operating Segments
Segment Reporting Information [Line Items]
Identifiable assets		2,540.6	2,613.5	2,695.2
Capital expenditures		15.4	22.3	23.0
Depreciation		15.8	17.1	18.1
Pool | Operating Segments
Segment Reporting Information [Line Items]
Identifiable assets	[1]	1,884.3	1,801.3	1,679.8
Capital expenditures		24.5	17.1	17.3
Depreciation		$ 14.3	$ 13.1	$ 11.4

[1] All cash and cash equivalents are included in “Corporate and other.”