Summary of Restructuring Charges by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 698	$ 2,134	$ 1,353	$ 3,370
2019 Restructuring
Restructuring Cost And Reserve [Line Items]
Restructuring costs	30	1,965	599	2,932
2019 Restructuring | Photonics
Restructuring Cost And Reserve [Line Items]
Restructuring costs	8	1,357	211	1,550
2019 Restructuring | Vision
Restructuring Cost And Reserve [Line Items]
Restructuring costs	2	306	291	656
2019 Restructuring | Precision Motion
Restructuring Cost And Reserve [Line Items]
Restructuring costs	14	147	78	194
2019 Restructuring | Unallocated Corporate and Shared Services
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 6	$ 155	$ 19	$ 532