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Segment Information (Details) $ in Millions	3 Months Ended
Segment Information (Details) $ in Millions	Mar. 31, 2019 USD ($) segment	Mar. 31, 2019 USD ($) item	Mar. 31, 2019 USD ($)	Apr. 01, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment information
Number of geographic segments	3	3
Revenue			$ 388.7	$ 378.5
Consolidated operating income (loss)			46.7	43.9
Interest income			(0.1)	(0.4)
Interest expense			3.6	4.3
Other expense, net			0.5	0.7
INCOME BEFORE INCOME TAXES			42.7	39.3
Capital Expenditures			6.9	7.3
Depreciation and Amortization			11.4	12.7
Identifiable assets (at end of period)	$ 1,683.4	$ 1,683.4	1,683.4	1,688.5	$ 1,653.7
Property, plant and equipment, net (at end of period)	199.6	199.6	199.6	201.1	$ 201.9
Residential & commercial flow control
Segment information
Revenue			203.5	196.6
HVAC & gas
Segment information
Revenue			119.3	120.7
Drainage & water re-use
Segment information
Revenue			40.5	38.4
Water quality
Segment information
Revenue			25.4	22.8
U.S.
Segment information
Property, plant and equipment, net (at end of period)	110.3	110.3	110.3	106.2
Reportable segments
Segment information
Consolidated operating income (loss)			57.6	52.7
Corporate
Segment information
Consolidated operating income (loss)			(10.9)	(8.8)
Intersegment sales
Segment information
Revenue			23.4	22.7
Americas
Segment information
Revenue			258.9	241.1
Capital Expenditures			3.9	4.6
Depreciation and Amortization			7.1	7.1
Identifiable assets (at end of period)	1,050.1	1,050.1	1,050.1	1,001.9
Property, plant and equipment, net (at end of period)	114.3	114.3	114.3	110.3
Americas \| Residential & commercial flow control
Segment information
Revenue			147.4	139.9
Americas \| HVAC & gas
Segment information
Revenue			68.7	62.5
Americas \| Drainage & water re-use
Segment information
Revenue			18.1	16.5
Americas \| Water quality
Segment information
Revenue			24.7	22.2
Americas \| U.S.
Segment information
Revenue			243.5	225.2
Americas \| Reportable segments
Segment information
Consolidated operating income (loss)			43.1	36.4
Americas \| Intersegment sales
Segment information
Revenue			2.9	2.6
Europe
Segment information
Revenue			116.3	123.0
Capital Expenditures			3.0	2.5
Depreciation and Amortization			3.6	4.9
Identifiable assets (at end of period)	524.9	524.9	524.9	548.2
Property, plant and equipment, net (at end of period)	78.7	78.7	78.7	83.7
Europe \| Residential & commercial flow control
Segment information
Revenue			45.4	47.2
Europe \| HVAC & gas
Segment information
Revenue			48.5	53.9
Europe \| Drainage & water re-use
Segment information
Revenue			21.9	21.6
Europe \| Water quality
Segment information
Revenue			0.5	0.3
Europe \| Reportable segments
Segment information
Consolidated operating income (loss)			13.2	14.9
Europe \| Intersegment sales
Segment information
Revenue			3.6	3.4
APMEA
Segment information
Revenue			13.5	14.4
Capital Expenditures				0.2
Depreciation and Amortization			0.7	0.7
Identifiable assets (at end of period)	108.4	108.4	108.4	138.4
Property, plant and equipment, net (at end of period)	$ 6.6	$ 6.6	6.6	7.1
APMEA \| Residential & commercial flow control
Segment information
Revenue			10.7	9.5
APMEA \| HVAC & gas
Segment information
Revenue			2.1	4.3
APMEA \| Drainage & water re-use
Segment information
Revenue			0.5	0.3
APMEA \| Water quality
Segment information
Revenue			0.2	0.3
APMEA \| Reportable segments
Segment information
Consolidated operating income (loss)			1.3	1.4
APMEA \| Intersegment sales
Segment information
Revenue			$ 16.9	$ 16.7