Summary of Restructuring Costs for Each Segment and Unallocated Corporate and Shared Services Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 1,466	$ 137	$ 4,836	$ 1,125
2019 Restructuring
Restructuring Cost And Reserve [Line Items]
Restructuring costs	1,115		4,047
2019 Restructuring | Unallocated Corporate and Shared Services
Restructuring Cost And Reserve [Line Items]
Restructuring costs	(67)		465
2019 Restructuring | Photonics
Restructuring Cost And Reserve [Line Items]
Restructuring costs	475		2,025
2019 Restructuring | Vision
Restructuring Cost And Reserve [Line Items]
Restructuring costs	367		1,023
2019 Restructuring | Precision Motion
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 340		$ 534