Summary of Restructuring Costs for Each Segment and Unallocated Corporate and Shared Services (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Restructuring Cost And Reserve [Line Items]
Restructuring Costs	$ 37	$ 2,712
2016 Restructuring
Restructuring Cost And Reserve [Line Items]
Restructuring Costs	33	2,500
2016 Restructuring | Photonics
Restructuring Cost And Reserve [Line Items]
Restructuring Costs		469
2016 Restructuring | Vision
Restructuring Cost And Reserve [Line Items]
Restructuring Costs	32	1,739
2016 Restructuring | Precision Motion
Restructuring Cost And Reserve [Line Items]
Restructuring Costs		87
2016 Restructuring | Unallocated Corporate and Shared Services
Restructuring Cost And Reserve [Line Items]
Restructuring Costs	$ 1	$ 205