Depreciation and Amortization by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016
Depreciation and Amortization
Depreciation and amortization	$ 8,864	$ 5,164	$ 22,440	$ 15,933
Photonics
Depreciation and Amortization
Depreciation and amortization	3,666	1,820	10,693	5,123
Vision
Depreciation and Amortization
Depreciation and amortization	4,362	2,460	9,276	7,861
Precision Motion
Depreciation and Amortization
Depreciation and amortization	588	603	1,746	1,845
Unallocated Corporate and Shared Services
Depreciation and Amortization
Depreciation and amortization	$ 248	$ 281	$ 725	$ 1,104