Depreciation and Amortization by Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Depreciation and Amortization
Depreciation and amortization	$ 20,973	$ 20,196	$ 24,421
Photonics
Depreciation and Amortization
Depreciation and amortization	6,738	6,083	6,481
Vision
Depreciation and Amortization
Depreciation and amortization	10,402	8,599	13,254
Precision Motion
Depreciation and Amortization
Depreciation and amortization	2,439	2,533	1,943
Unallocated Corporate and Shared Services
Depreciation and Amortization
Depreciation and amortization	$ 1,394	$ 2,981	$ 2,743