Segment Information (Reconciliation) (Details) $ in Millions	3 Months Ended
	Apr. 02, 2017 USD ($) product_line	Apr. 03, 2016 USD ($)
Net sales:
Net sales	$ 566.1	$ 530.5
Net sales, percentage change	6.70%
Operating income(b):
Operating income	$ 58.1	60.9
Total segment operating profit, percentage change	(4.60%)
Corporate, Non-Segment
Operating income(b):
Operating income	$ (22.7)	(10.8)
Total segment operating profit, percentage change	110.20%
Intersegment Eliminations
Net sales:
Net sales	$ 3.9	5.1
Instrumentation
Segment Reporting Information [Line Items]
Number of product lines | product_line	3
Instrumentation | Operating Segments
Net sales:
Net sales	$ 232.8	223.7
Net sales, percentage change	4.10%
Operating income(b):
Operating income	$ 30.4	31.4
Total segment operating profit, percentage change	(3.20%)
Digital Imaging
Segment Reporting Information [Line Items]
Number of product lines | product_line	1
Digital Imaging | Operating Segments
Net sales:
Net sales	$ 113.8	89.9
Net sales, percentage change	26.60%
Operating income(b):
Operating income	$ 15.3	8.2
Total segment operating profit, percentage change	86.60%
Aerospace and Defense Electronics
Segment Reporting Information [Line Items]
Number of product lines | product_line	1
Aerospace and Defense Electronics | Operating Segments
Net sales:
Net sales	$ 151.9	152.6
Net sales, percentage change	(0.50%)
Operating income(b):
Operating income	$ 26.2	24.1
Total segment operating profit, percentage change	8.70%
Engineered Systems
Segment Reporting Information [Line Items]
Number of product lines | product_line	1
Engineered Systems | Operating Segments
Net sales:
Net sales	$ 67.6	64.3
Net sales, percentage change	5.10%
Operating income(b):
Operating income	$ 8.9	$ 8.0
Total segment operating profit, percentage change	11.30%
e2v
Operating income(b):
Operating income	$ (2.5)
e2v | Cost Of Sales And Sales General And Administrative Expenses
Operating income(b):
Transaction costs	12.9
e2v | Cost Of Sales And Sales General And Administrative Expenses | Corporate, Non-Segment
Operating income(b):
Transaction costs	10.4
e2v | Cost Of Sales And Sales General And Administrative Expenses | Digital Imaging
Operating income(b):
Transaction costs	$ 2.5