Segment Information (Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Net sales:
Net sales	$ 784.6	$ 745.2
Net sales, percentage change	5.30%
Operating income:
Operating income	$ 104.0	97.3
Total segment operating profit, percentage change	6.90%
Corporate, Non-Segment
Operating income:
Operating income	$ (15.4)	(18.1)
Total segment operating profit, percentage change	(14.90%)
Intersegment Eliminations
Net sales:
Net sales	$ 6.9	6.4
Instrumentation
Net sales:
Net sales	285.1	256.5
Instrumentation | Operating Segments
Net sales:
Net sales	$ 285.1	256.5
Net sales, percentage change	11.20%
Operating income:
Operating income	$ 50.8	39.9
Total segment operating profit, percentage change	27.30%
Digital Imaging
Net sales:
Net sales	$ 246.7	232.4
Digital Imaging | Operating Segments
Net sales:
Net sales	$ 246.7	232.4
Net sales, percentage change	6.20%
Operating income:
Operating income	$ 43.8	36.6
Total segment operating profit, percentage change	19.70%
Aerospace and Defense Electronics
Net sales:
Net sales	$ 156.3	166.6
Aerospace and Defense Electronics | Operating Segments
Net sales:
Net sales	$ 156.3	166.6
Net sales, percentage change	(6.20%)
Operating income:
Operating income	$ 13.4	32.5
Total segment operating profit, percentage change	(58.80%)
Engineered Systems
Net sales:
Net sales	$ 96.5	89.7
Engineered Systems | Operating Segments
Net sales:
Net sales	$ 96.5	89.7
Net sales, percentage change	7.60%
Operating income:
Operating income	$ 11.4	$ 6.4
Total segment operating profit, percentage change	78.10%