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Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
Segment Information (Details) $ in Millions	Dec. 31, 2019 USD ($)	Sep. 29, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Apr. 01, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment information
Number of geographic segments										3	3
Revenue	$ 400.3	$ 394.7	$ 416.8	$ 388.7	$ 387.6	$ 390.9	$ 407.9	$ 378.5	$ 1,600.5			$ 1,564.9	$ 1,456.7
Consolidated operating income (loss)									197.1			188.4	162.3
Interest income									(0.4)			(0.8)	(1.0)
Interest expense									14.1			16.3	19.1
Other expense, net									(0.5)			(1.7)	1.1
INCOME BEFORE INCOME TAXES									183.9			174.6	143.1
Capital Expenditures									29.2			35.9	29.4
Depreciation and Amortization									46.6			48.5	52.2
Identifiable assets (at end of period)	1,723.1				1,653.7				1,723.1	$ 1,723.1	$ 1,723.1	1,653.7	1,736.5
Property, plant and equipment, net (at end of period)	200.0				201.9				200.0	200.0	200.0	201.9	198.5
Goodwill impairment charge									0.0
Residential & Commercial Flow Control
Segment information
Revenue									827.5			804.4
HVAC & Gas Products
Segment information
Revenue									498.0			507.0
Drainage & Water Re-use Products
Segment information
Revenue									172.4			163.1
Water Quality Products
Segment information
Revenue									102.6			90.4
Reportable segments
Segment information
Consolidated operating income (loss)									244.2			228.1	199.1
Corporate
Segment information
Consolidated operating income (loss)									(47.1)			(39.7)	(36.8)
Intersegment sales
Segment information
Revenue									95.0			115.3	96.4
Americas
Segment information
Revenue									1,084.1			1,032.1	951.9
Capital Expenditures									18.3			21.5	20.7
Depreciation and Amortization									29.3			29.1	30.8
Identifiable assets (at end of period)	1,102.9				1,028.1				1,102.9	1,102.9	1,102.9	1,028.1	1,069.2
Property, plant and equipment, net (at end of period)	116.7				115.0				116.7	116.7	116.7	115.0	109.3
Americas \| Residential & Commercial Flow Control
Segment information
Revenue									610.5			582.0
Americas \| HVAC & Gas Products
Segment information
Revenue									294.6			289.2
Americas \| Drainage & Water Re-use Products
Segment information
Revenue									80.2			73.1
Americas \| Water Quality Products
Segment information
Revenue									98.8			87.8
Americas \| U.S.
Segment information
Revenue									1,014.0			964.2	886.2
Property, plant and equipment, net (at end of period)	112.6				111.0				112.6	112.6	112.6	111.0	105.1
Americas \| Reportable segments
Segment information
Consolidated operating income (loss)									187.4			171.1	146.8
Americas \| Intersegment sales
Segment information
Revenue									12.1			12.7	12.1
Europe
Segment information
Revenue									451.0			467.0	440.3
Capital Expenditures									10.3			12.7	8.0
Depreciation and Amortization									14.6			16.7	18.6
Identifiable assets (at end of period)	515.2				510.2				515.2	515.2	515.2	510.2	524.0
Property, plant and equipment, net (at end of period)	77.5				80.0				77.5	77.5	77.5	80.0	82.1
Europe \| Residential & Commercial Flow Control
Segment information
Revenue									171.3			176.2
Europe \| HVAC & Gas Products
Segment information
Revenue									188.2			201.6
Europe \| Drainage & Water Re-use Products
Segment information
Revenue									88.8			87.8
Europe \| Water Quality Products
Segment information
Revenue									2.7			1.4
Europe \| Reportable segments
Segment information
Consolidated operating income (loss)									49.9			49.8	47.6
Europe \| Intersegment sales
Segment information
Revenue									15.2			14.2	14.6
APMEA
Segment information
Revenue									65.4			65.8	64.5
Capital Expenditures									0.6			1.7	0.7
Depreciation and Amortization									2.7			2.7	2.8
Identifiable assets (at end of period)	105.0				115.4				105.0	105.0	105.0	115.4	143.3
Property, plant and equipment, net (at end of period)	$ 5.8				$ 6.9				5.8	$ 5.8	$ 5.8	6.9	7.1
APMEA \| Residential & Commercial Flow Control
Segment information
Revenue									45.7			46.2
APMEA \| HVAC & Gas Products
Segment information
Revenue									15.2			16.2
APMEA \| Drainage & Water Re-use Products
Segment information
Revenue									3.4			2.2
APMEA \| Water Quality Products
Segment information
Revenue									1.1			1.2
APMEA \| Reportable segments
Segment information
Consolidated operating income (loss)									6.9			7.2	4.7
APMEA \| Intersegment sales
Segment information
Revenue									$ 67.7			$ 88.4	$ 69.7