Depreciation and Amortization Expenses by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Depreciation and Amortization Expenses
Depreciation and amortization expenses	$ 10,890	$ 9,596	$ 30,613	$ 28,363
Unallocated Corporate and Shared Services
Depreciation and Amortization Expenses
Depreciation and amortization expenses	59	67	201	160
Photonics | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	2,901	2,864	8,703	8,303
Vision | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	5,239	5,296	15,793	15,845
Precision Motion | Operating Segments
Depreciation and Amortization Expenses
Depreciation and amortization expenses	$ 2,691	$ 1,369	$ 5,916	$ 4,055