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Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
Segment Information (Details) $ in Millions	Sep. 29, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 29, 2019 USD ($) segment	Sep. 29, 2019 USD ($) item	Sep. 29, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment information
Number of geographic segments			3	3
Revenue	$ 394.7	$ 390.9			$ 1,200.2	$ 1,177.3
Consolidated operating income (loss)	48.8	46.9			149.8	143.0
Interest income	(0.1)	(0.1)			(0.3)	(0.6)
Interest expense	3.5	3.9			10.8	12.6
Other expense, net	(0.8)	(0.9)			(0.4)	(2.0)
INCOME BEFORE INCOME TAXES	46.2	44.0			139.7	133.0
Capital Expenditures	4.7	8.9			19.1	24.1
Depreciation and Amortization	11.6	11.7			34.3	36.7
Identifiable assets (at end of period)	1,696.3	1,649.6	$ 1,696.3	$ 1,696.3	1,696.3	1,649.6	$ 1,653.7
Property, plant and equipment, net (at end of period)	195.8	198.5	195.8	195.8	195.8	198.5	$ 201.9
Residential & commercial flow control
Segment information
Revenue	202.7	195.8			622.7	601.3
HVAC & gas
Segment information
Revenue	122.5	130.8			370.9	386.5
Drainage & water re-use
Segment information
Revenue	43.5	42.2			129.8	122.5
Water quality
Segment information
Revenue	26.0	22.1			76.8	67.0
U.S.
Segment information
Property, plant and equipment, net (at end of period)	109.6	109.0	109.6	109.6	109.6	109.0
Reportable segments
Segment information
Consolidated operating income (loss)	62.0	56.9			184.3	170.8
Corporate
Segment information
Consolidated operating income (loss)	(13.2)	(10.0)			(34.5)	(27.8)
Intersegment sales
Segment information
Revenue	24.3	34.7			73.8	89.0
Americas
Segment information
Revenue	270.3	262.7			816.2	775.8
Capital Expenditures	3.1	5.1			10.5	15.0
Depreciation and Amortization	7.3	7.4			21.6	21.7
Identifiable assets (at end of period)	1,098.1	1,024.2	1,098.1	1,098.1	1,098.1	1,024.2
Property, plant and equipment, net (at end of period)	113.5	113.0	113.5	113.5	113.5	113.0
Americas \| Residential & commercial flow control
Segment information
Revenue	151.0	144.4			459.7	435.3
Americas \| HVAC & gas
Segment information
Revenue	73.4	77.1			221.9	220.2
Americas \| Drainage & water re-use
Segment information
Revenue	20.7	19.8			60.4	55.2
Americas \| Water quality
Segment information
Revenue	25.2	21.4			74.2	65.1
Americas \| U.S.
Segment information
Revenue	252.0	245.5			764.9	725.1
Americas \| Reportable segments
Segment information
Consolidated operating income (loss)	48.5	45.0			142.3	128.1
Americas \| Intersegment sales
Segment information
Revenue	3.2	3.7			9.1	9.7
Europe
Segment information
Revenue	107.9	111.6			337.4	351.7
Capital Expenditures	1.5	3.4			8.1	8.1
Depreciation and Amortization	3.6	3.7			10.7	13.1
Identifiable assets (at end of period)	504.6	520.2	504.6	504.6	504.6	520.2
Property, plant and equipment, net (at end of period)	76.4	78.9	76.4	76.4	76.4	78.9
Europe \| Residential & commercial flow control
Segment information
Revenue	41.1	40.2			130.1	132.2
Europe \| HVAC & gas
Segment information
Revenue	44.7	49.4			139.0	152.7
Europe \| Drainage & water re-use
Segment information
Revenue	21.5	21.7			66.4	65.9
Europe \| Water quality
Segment information
Revenue	0.6	0.3			1.9	0.9
Europe \| Reportable segments
Segment information
Consolidated operating income (loss)	12.1	9.4			38.1	37.2
Europe \| Intersegment sales
Segment information
Revenue	3.4	3.7			11.3	10.6
APMEA
Segment information
Revenue	16.5	16.6			46.6	49.8
Capital Expenditures	0.1	0.4			0.5	1.0
Depreciation and Amortization	0.7	0.6			2.0	1.9
Identifiable assets (at end of period)	93.6	105.2	93.6	93.6	93.6	105.2
Property, plant and equipment, net (at end of period)	5.9	6.6	$ 5.9	$ 5.9	5.9	6.6
APMEA \| Residential & commercial flow control
Segment information
Revenue	10.6	11.2			32.9	33.8
APMEA \| HVAC & gas
Segment information
Revenue	4.4	4.3			10.0	13.6
APMEA \| Drainage & water re-use
Segment information
Revenue	1.3	0.7			3.0	1.4
APMEA \| Water quality
Segment information
Revenue	0.2	0.4			0.7	1.0
APMEA \| Reportable segments
Segment information
Consolidated operating income (loss)	1.4	2.5			3.9	5.5
APMEA \| Intersegment sales
Segment information
Revenue	$ 17.7	$ 27.3			$ 53.4	$ 68.7