Segment Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 27, 2021 USD ($)	Jun. 28, 2020 USD ($)	Jun. 27, 2021 USD ($)	Jun. 27, 2021 USD ($) segment	Jun. 27, 2021 USD ($) item	Jun. 28, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment information
Number of geographic segments				3	3
Net sales	$ 467.0	$ 338.7	$ 880.3			$ 721.3
Operating income	52.7	31.0	112.3			78.8
Interest income		(0.1)				(0.2)
Interest expense	1.5	4.0	3.5			7.0
Other expense (income), net	(0.5)	(0.4)	(0.8)			(0.1)
INCOME BEFORE INCOME TAXES	51.7	27.5	109.6			72.1
Capital expenditures	8.3	14.9	13.0			23.8
Depreciation and amortization	11.5	11.5	23.3			22.9
Identifiable assets (at end of period)	1,855.3	1,648.3	1,855.3	$ 1,855.3	$ 1,855.3	1,648.3	$ 1,738.2
Property, plant and equipment, net (at end of period)	207.0	206.9	207.0	207.0	207.0	206.9	$ 212.3
Residential & Commercial Flow Control
Segment information
Net sales	247.6	170.3	471.9			368.1
HVAC & Gas Products
Segment information
Net sales	142.1	105.5	264.5			219.1
Drainage & Water Re-use Products
Segment information
Net sales	48.2	37.4	87.4			79.9
Water Quality Products
Segment information
Net sales	29.1	25.5	56.5			54.2
U.S.
Segment information
Net sales	285.0	222.6	539.4			469.3
Reportable segments
Segment information
Operating income	64.9	39.5	135.2			96.5
Corporate
Segment information
Operating income	(12.2)	(8.5)	(22.9)			(17.7)
Intersegment sales
Segment information
Net sales	48.1	29.2	84.5			49.5
Americas
Segment information
Net sales	307.1	237.4	579.9			499.8
Capital expenditures	4.8	11.1	7.2			17.7
Depreciation and amortization	7.4	7.5	15.1			14.9
Identifiable assets (at end of period)	1,127.2	1,079.0	1,127.2	1,127.2	1,127.2	1,079.0
Property, plant and equipment, net (at end of period)	120.6	123.9	120.6	120.6	120.6	123.9
Americas | Residential & Commercial Flow Control
Segment information
Net sales	177.2	130.7	339.5			279.4
Americas | HVAC & Gas Products
Segment information
Net sales	77.6	63.0	143.5			130.6
Americas | Drainage & Water Re-use Products
Segment information
Net sales	25.2	19.3	43.8			37.8
Americas | Water Quality Products
Segment information
Net sales	27.1	24.4	53.1			52.0
Americas | U.S.
Segment information
Property, plant and equipment, net (at end of period)	116.0	120.0	116.0	116.0	116.0	120.0
Americas | Reportable segments
Segment information
Operating income	55.2	29.5	103.7			72.9
Americas | Intersegment sales
Segment information
Net sales	2.5	2.9	4.9			5.5
Europe
Segment information
Net sales	136.8	88.1	259.7			198.3
Capital expenditures	2.9	3.8	5.2			6.0
Depreciation and amortization	3.0	3.5	6.3			6.9
Identifiable assets (at end of period)	586.7	479.7	586.7	586.7	586.7	479.7
Property, plant and equipment, net (at end of period)	81.5	77.8	81.5	81.5	81.5	77.8
Europe | Residential & Commercial Flow Control
Segment information
Net sales	51.8	30.7	99.1			71.7
Europe | HVAC & Gas Products
Segment information
Net sales	60.9	38.5	115.1			82.9
Europe | Drainage & Water Re-use Products
Segment information
Net sales	22.5	18.1	42.7			42.0
Europe | Water Quality Products
Segment information
Net sales	1.6	0.8	2.8			1.7
Europe | Reportable segments
Segment information
Operating income	5.4	9.2	24.9			22.9
Europe | Intersegment sales
Segment information
Net sales	8.5	5.3	16.2			9.5
APMEA
Segment information
Net sales	23.1	13.2	40.7			23.2
Capital expenditures	0.6		0.6			0.1
Depreciation and amortization	1.1	0.5	1.9			1.1
Identifiable assets (at end of period)	141.4	89.6	141.4	141.4	141.4	89.6
Property, plant and equipment, net (at end of period)	4.9	5.2	4.9	$ 4.9	$ 4.9	5.2
APMEA | Residential & Commercial Flow Control
Segment information
Net sales	18.6	8.9	33.3			17.0
APMEA | HVAC & Gas Products
Segment information
Net sales	3.6	4.0	5.9			5.6
APMEA | Drainage & Water Re-use Products
Segment information
Net sales	0.5		0.9			0.1
APMEA | Water Quality Products
Segment information
Net sales	0.4	0.3	0.6			0.5
APMEA | Reportable segments
Segment information
Operating income	4.3	0.8	6.6			0.7
APMEA | Intersegment sales
Segment information
Net sales	$ 37.1	$ 21.0	$ 63.4			$ 34.5