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Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
Segment Information (Details) $ in Millions	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Apr. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Apr. 02, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2018 USD ($) item	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment information
Number of geographic segments									3	3
Revenue	$ 387.6	$ 390.9	$ 407.9	$ 378.5	$ 366.3	$ 364.7	$ 378.5	$ 347.2			$ 1,564.9	$ 1,456.7	$ 1,398.4
Consolidated operating income (loss)											188.4	162.3	145.0
Interest income											(0.8)	(1.0)	(1.0)
Interest expense											16.3	19.1	22.6
Other (income) expense, net											(1.7)	1.1	(4.4)
INCOME BEFORE INCOME TAXES											174.6	143.1	127.8
Capital Expenditures											35.9	29.4	36.0
Depreciation and Amortization											48.5	52.2	51.2
Identifiable assets (at end of period)	1,653.7				1,736.5				$ 1,653.7	$ 1,653.7	1,653.7	1,736.5	1,763.2
Property, plant and equipment, net (at end of period)	201.9				198.5				201.9	201.9	201.9	198.5	189.7
Goodwill impairment charge											0.0	0.0
Gain on disposition													8.7
Residential & commercial flow control
Segment information
Revenue											804.4
HVAC & gas
Segment information
Revenue											507.0
Drainage & water re-use
Segment information
Revenue											163.1
Water quality
Segment information
Revenue											90.4
Reportable segments
Segment information
Consolidated operating income (loss)											228.1	199.1	182.2
Corporate
Segment information
Consolidated operating income (loss)											(39.7)	(36.8)	(37.2)
Intersegment sales
Segment information
Revenue											115.3	96.4	101.0
Americas
Segment information
Revenue											1,032.1	951.9	900.9
Capital Expenditures											21.5	20.7	25.7
Depreciation and Amortization											29.1	30.8	28.8
Identifiable assets (at end of period)	1,028.1				1,069.2				1,028.1	1,028.1	1,028.1	1,069.2	1,054.7
Property, plant and equipment, net (at end of period)	115.0				109.3				115.0	115.0	115.0	109.3	106.2
Americas \| Residential & commercial flow control
Segment information
Revenue											582.0
Americas \| HVAC & gas
Segment information
Revenue											289.2
Americas \| Drainage & water re-use
Segment information
Revenue											73.1
Americas \| Water quality
Segment information
Revenue											87.8
Americas \| U.S.
Segment information
Revenue											964.2	886.2	839.2
Property, plant and equipment, net (at end of period)	111.0				105.1				111.0	111.0	111.0	105.1	102.5
Americas \| Reportable segments
Segment information
Consolidated operating income (loss)											171.1	146.8	127.1
Americas \| Intersegment sales
Segment information
Revenue											12.7	12.1	12.0
Europe
Segment information
Revenue											467.0	440.3	431.3
Capital Expenditures											12.7	8.0	8.9
Depreciation and Amortization											16.7	18.6	19.3
Identifiable assets (at end of period)	510.2				524.0				510.2	510.2	510.2	524.0	577.3
Property, plant and equipment, net (at end of period)	80.0				82.1				80.0	80.0	80.0	82.1	75.6
Europe \| Residential & commercial flow control
Segment information
Revenue											176.2
Europe \| HVAC & gas
Segment information
Revenue											201.6
Europe \| Drainage & water re-use
Segment information
Revenue											87.8
Europe \| Water quality
Segment information
Revenue											1.4
Europe \| Reportable segments
Segment information
Consolidated operating income (loss)											49.8	47.6	40.0
Europe \| Intersegment sales
Segment information
Revenue											14.2	14.6	12.3
APMEA
Segment information
Revenue											65.8	64.5	66.2
Capital Expenditures											1.7	0.7	1.4
Depreciation and Amortization											2.7	2.8	3.1
Identifiable assets (at end of period)	115.4				143.3				115.4	115.4	115.4	143.3	131.2
Property, plant and equipment, net (at end of period)	$ 6.9				$ 7.1				$ 6.9	$ 6.9	6.9	7.1	7.9
Gain on disposition													8.7
APMEA \| Residential & commercial flow control
Segment information
Revenue											46.2
APMEA \| HVAC & gas
Segment information
Revenue											16.2
APMEA \| Drainage & water re-use
Segment information
Revenue											2.2
APMEA \| Water quality
Segment information
Revenue											1.2
APMEA \| Reportable segments
Segment information
Consolidated operating income (loss)											7.2	4.7	15.1
APMEA \| Intersegment sales
Segment information
Revenue											$ 88.4	$ 69.7	$ 76.7