Depreciation and Amortization by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Depreciation and Amortization
Depreciation and amortization	$ 9,120	$ 7,094	$ 18,187	$ 13,576
Photonics
Depreciation and Amortization
Depreciation and amortization	2,966	3,783	6,033	7,027
Vision
Depreciation and Amortization
Depreciation and amortization	5,097	2,477	10,271	4,914
Precision Motion
Depreciation and Amortization
Depreciation and amortization	841	592	1,344	1,158
Unallocated Corporate and Shared Services
Depreciation and Amortization
Depreciation and amortization	$ 216	$ 242	$ 539	$ 477