Summary of Restructuring Program By Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2020	Mar. 29, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 655	$ 1,236
2019 Restructuring
Restructuring Cost And Reserve [Line Items]
Restructuring costs	569	967
2019 Restructuring | Photonics
Restructuring Cost And Reserve [Line Items]
Restructuring costs	203	193
2019 Restructuring | Vision
Restructuring Cost And Reserve [Line Items]
Restructuring costs	289	350
2019 Restructuring | Precision Motion
Restructuring Cost And Reserve [Line Items]
Restructuring costs	64	47
2019 Restructuring | Unallocated Corporate and Shared Services
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 13	$ 377