Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 28, 2021 USD ($)	Mar. 28, 2021 USD ($) segment	Mar. 28, 2021 USD ($) item	Mar. 29, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment information
Number of geographic segments		3	3
Net sales	$ 413.3			$ 382.6
Operating income	59.6			47.8
Interest income				(0.1)
Interest expense	2.0			3.0
Other expense (income), net	(0.3)			0.3
INCOME BEFORE INCOME TAXES	57.9			44.6
Capital expenditures	4.9			8.9
Depreciation and amortization	11.8			11.4
Identifiable assets (at end of period)	1,784.4	$ 1,784.4	$ 1,784.4	1,767.4	$ 1,738.2
Property, plant and equipment, net (at end of period)	205.8	205.8	205.8	201.8	$ 212.3
Residential & Commercial Flow Control
Segment information
Net sales	224.2			197.7
HVAC & Gas Products
Segment information
Net sales	122.4			113.6
Drainage & Water Re-use Products
Segment information
Net sales	39.3			42.7
Water Quality Products
Segment information
Net sales	27.4			28.6
U.S.
Segment information
Net sales	254.4			246.7
Reportable segments
Segment information
Operating income	70.3			57.0
Corporate
Segment information
Operating income	(10.7)			(9.2)
Intersegment sales
Segment information
Net sales	36.4			20.1
Americas
Segment information
Net sales	272.8			262.4
Capital expenditures	2.5			6.6
Depreciation and amortization	7.7			7.4
Identifiable assets (at end of period)	1,105.0	1,105.0	1,105.0	1,155.4
Property, plant and equipment, net (at end of period)	120.3	120.3	120.3	121.0
Americas | Residential & Commercial Flow Control
Segment information
Net sales	162.3			148.7
Americas | HVAC & Gas Products
Segment information
Net sales	65.9			67.6
Americas | Drainage & Water Re-use Products
Segment information
Net sales	18.6			18.5
Americas | Water Quality Products
Segment information
Net sales	26.0			27.6
Americas | U.S.
Segment information
Property, plant and equipment, net (at end of period)	116.2	116.2	116.2	117.2
Americas | Reportable segments
Segment information
Operating income	48.5			43.4
Americas | Intersegment sales
Segment information
Net sales	2.5			2.4
Europe
Segment information
Net sales	122.9			110.2
Capital expenditures	2.4			2.2
Depreciation and amortization	3.3			3.4
Identifiable assets (at end of period)	549.4	549.4	549.4	519.6
Property, plant and equipment, net (at end of period)	80.4	80.4	80.4	75.4
Europe | Residential & Commercial Flow Control
Segment information
Net sales	47.2			41.0
Europe | HVAC & Gas Products
Segment information
Net sales	54.2			44.4
Europe | Drainage & Water Re-use Products
Segment information
Net sales	20.3			23.9
Europe | Water Quality Products
Segment information
Net sales	1.2			0.9
Europe | Reportable segments
Segment information
Operating income	19.5			13.7
Europe | Intersegment sales
Segment information
Net sales	7.6			4.1
APMEA
Segment information
Net sales	17.6			10.0
Capital expenditures				0.1
Depreciation and amortization	0.8			0.6
Identifiable assets (at end of period)	130.0	130.0	130.0	92.4
Property, plant and equipment, net (at end of period)	5.1	$ 5.1	$ 5.1	5.4
APMEA | Residential & Commercial Flow Control
Segment information
Net sales	14.7			8.0
APMEA | HVAC & Gas Products
Segment information
Net sales	2.3			1.6
APMEA | Drainage & Water Re-use Products
Segment information
Net sales	0.4			0.3
APMEA | Water Quality Products
Segment information
Net sales	0.2			0.1
APMEA | Reportable segments
Segment information
Operating income	2.3			(0.1)
APMEA | Intersegment sales
Segment information
Net sales	$ 26.3			$ 13.6