Segment Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 28, 2020 USD ($)	Jun. 28, 2020 USD ($) segment	Jun. 28, 2020 USD ($) item	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment information
Number of geographic segments				3	3
Revenue	$ 338.7	$ 416.8	$ 721.3			$ 805.5
Consolidated operating income	31.0	54.3	78.8			101.0
Interest income	(0.1)	(0.1)	(0.2)			(0.2)
Interest expense	4.0	3.7	7.0			7.3
Other (income) expense, net	(0.4)	(0.1)	(0.1)			0.4
INCOME BEFORE INCOME TAXES	27.5	50.8	72.1			93.5
Capital Expenditures	14.9	7.4	23.8			14.3
Depreciation and Amortization	11.5	11.4	22.9			22.8
Identifiable assets (at end of period)	1,648.3	1,678.4	1,648.3	$ 1,648.3	$ 1,648.3	1,678.4	$ 1,723.1
Property, plant and equipment, net (at end of period)	206.9	200.9	206.9	206.9	206.9	200.9	$ 200.0
Residential & Commercial Flow Control
Segment information
Revenue	170.3	216.5	368.1			420.1
HVAC & Gas Products
Segment information
Revenue	105.5	129.3	219.1			248.5
Drainage & Water Re-use Products
Segment information
Revenue	37.4	45.7	79.9			86.2
Water Quality Products
Segment information
Revenue	25.5	25.3	54.2			50.7
Reportable segments
Segment information
Consolidated operating income	39.5	64.7	96.5			122.2
Corporate
Segment information
Consolidated operating income	(8.5)	(10.4)	(17.7)			(21.2)
Intersegment sales
Segment information
Revenue	29.2	26.0	49.5			49.5
Americas
Segment information
Revenue	237.4	287.0	499.8			545.9
Capital Expenditures	11.1	3.6	17.7			7.5
Depreciation and Amortization	7.5	7.2	14.9			14.3
Identifiable assets (at end of period)	1,079.0	1,052.4	1,079.0	1,079.0	1,079.0	1,052.4
Property, plant and equipment, net (at end of period)	123.9	114.0	123.9	123.9	123.9	114.0
Americas | Residential & Commercial Flow Control
Segment information
Revenue	130.7	161.3	279.4			308.7
Americas | HVAC & Gas Products
Segment information
Revenue	63.0	79.8	130.6			148.5
Americas | Drainage & Water Re-use Products
Segment information
Revenue	19.3	21.6	37.8			39.7
Americas | Water Quality Products
Segment information
Revenue	24.4	24.3	52.0			49.0
Americas | U.S.
Segment information
Revenue	222.6	269.4	469.3			512.9
Property, plant and equipment, net (at end of period)	120.0	109.9	120.0	120.0	120.0	109.9
Americas | Reportable segments
Segment information
Consolidated operating income	29.5	50.7	72.9			93.8
Americas | Intersegment sales
Segment information
Revenue	2.9	3.0	5.5			5.9
Europe
Segment information
Revenue	88.1	113.2	198.3			229.5
Capital Expenditures	3.8	3.5	6.0			6.5
Depreciation and Amortization	3.5	3.5	6.9			7.1
Identifiable assets (at end of period)	479.7	516.3	479.7	479.7	479.7	516.3
Property, plant and equipment, net (at end of period)	77.8	80.5	77.8	77.8	77.8	80.5
Europe | Residential & Commercial Flow Control
Segment information
Revenue	30.7	43.6	71.7			89.1
Europe | HVAC & Gas Products
Segment information
Revenue	38.5	45.9	82.9			94.3
Europe | Drainage & Water Re-use Products
Segment information
Revenue	18.1	23.0	42.0			44.9
Europe | Water Quality Products
Segment information
Revenue	0.8	0.7	1.7			1.2
Europe | Reportable segments
Segment information
Consolidated operating income	9.2	12.8	22.9			26.0
Europe | Intersegment sales
Segment information
Revenue	5.3	4.2	9.5			7.9
APMEA
Segment information
Revenue	13.2	16.6	23.2			30.1
Capital Expenditures		0.3	0.1			0.3
Depreciation and Amortization	0.5	0.7	1.1			1.4
Identifiable assets (at end of period)	89.6	109.7	89.6	89.6	89.6	109.7
Property, plant and equipment, net (at end of period)	5.2	6.4	5.2	$ 5.2	$ 5.2	6.4
APMEA | Residential & Commercial Flow Control
Segment information
Revenue	8.9	11.6	17.0			22.3
APMEA | HVAC & Gas Products
Segment information
Revenue	4.0	3.6	5.6			5.7
APMEA | Drainage & Water Re-use Products
Segment information
Revenue		1.1	0.1			1.6
APMEA | Water Quality Products
Segment information
Revenue	0.3	0.3	0.5			0.5
APMEA | Reportable segments
Segment information
Consolidated operating income	0.8	1.2	0.7			2.4
APMEA | Intersegment sales
Segment information
Revenue	$ 21.0	$ 18.8	$ 34.5			$ 35.7