Depreciation and Amortization Expenses by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2021	Apr. 03, 2020
Depreciation and Amortization Expenses
Depreciation and amortization expenses	$ 9,849	$ 9,330
Unallocated Corporate and Shared Services
Depreciation and Amortization Expenses
Depreciation and amortization expenses	69	51
Photonics | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	2,898	2,649
Vision | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	5,275	5,277
Precision Motion | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	$ 1,607	$ 1,353