Segment Information (Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Oct. 02, 2016	Sep. 27, 2015
Net sales:
Net sales	$ 526.8	$ 551.7	$ 1,586.9	$ 1,686.8
Net sales, percentage change	(4.50%)		(5.90%)
Operating income:
Operating income	$ 70.5	71.8	$ 185.8	208.5
Total segment operating profit, percentage change	(1.80%)		(10.90%)
Corporate, Non-Segment
Operating income:
Operating income	$ (11.1)	(8.9)	$ (32.7)	(30.1)
Total segment operating profit, percentage change	24.70%		8.60%
Intersegment Eliminations
Net sales:
Net sales	$ 4.2	4.8	$ 16.2	14.7
Instrumentation | Operating Segments
Net sales:
Net sales	$ 208.3	243.2	$ 652.1	784.8
Net sales, percentage change	(14.40%)		(16.90%)
Operating income:
Operating income	$ 28.1	38.6	$ 79.6	126.4
Total segment operating profit, percentage change	(27.20%)		(37.00%)
Digital Imaging | Operating Segments
Net sales:
Net sales	$ 98.5	95.7	$ 287.8	276.9
Net sales, percentage change	2.90%		3.90%
Operating income:
Operating income	$ 11.7	10.4	$ 30.6	28.5
Total segment operating profit, percentage change	12.50%		7.40%
Aerospace and Defense Electronics | Operating Segments
Net sales:
Net sales	$ 153.5	147.6	$ 454.0	428.2
Net sales, percentage change	4.00%		6.00%
Operating income:
Operating income	$ 33.2	25.8	$ 86.1	66.3
Total segment operating profit, percentage change	28.70%		29.90%
Engineered Systems | Operating Segments
Net sales:
Net sales	$ 66.5	65.2	$ 193.0	196.9
Net sales, percentage change	2.00%		(2.00%)
Operating income:
Operating income	$ 8.6	$ 5.9	$ 22.2	$ 17.4
Total segment operating profit, percentage change	45.80%		27.60%