Segment Information (Identifiable Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Identifiable assets	$ 3,913.2	$ 3,846.4
Operating Segments | Instrumentation
Segment Reporting Information [Line Items]
Identifiable assets	1,378.0	1,413.6
Operating Segments | Digital Imaging
Segment Reporting Information [Line Items]
Identifiable assets	1,613.8	1,606.5
Operating Segments | Aerospace and Defense Electronics
Segment Reporting Information [Line Items]
Identifiable assets	527.9	495.4
Operating Segments | Engineered Systems
Segment Reporting Information [Line Items]
Identifiable assets	118.2	107.0
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Identifiable assets	$ 275.3	$ 223.9