Segment Information (Sales) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Revenue from External Customer [Line Items]
Net sales	$ 782.0	$ 732.5	$ 1,527.2	$ 1,428.1
Instrumentation
Revenue from External Customer [Line Items]
Net sales	264.1	262.6	520.6	501.6
Operating Segments | Instrumentation
Revenue from External Customer [Line Items]
Net sales	264.1	262.6	520.6	501.6
Operating Segments | Instrumentation | Marine Instrumentation
Revenue from External Customer [Line Items]
Net sales	111.4	118.7	216.6	222.9
Operating Segments | Instrumentation | Environmental Instrumentation
Revenue from External Customer [Line Items]
Net sales	87.4	85.7	173.8	166.9
Operating Segments | Instrumentation | Test and Measurement Instrumentation
Revenue from External Customer [Line Items]
Net sales	$ 65.3	$ 58.2	$ 130.2	$ 111.8