Goodwill By Reportable Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 254,685	$ 241,975
Accumulated impairment of goodwill	(151,229)	(151,229)
Total	103,456	90,746
Laser Products
Goodwill [Line Items]
Goodwill	136,321	132,954
Accumulated impairment of goodwill	(102,461)	(102,461)
Total	33,860	30,493
Vision Technologies
Goodwill [Line Items]
Goodwill	84,401	82,730
Accumulated impairment of goodwill	(31,722)	(31,722)
Total	52,679	51,008
Precision Motion
Goodwill [Line Items]
Goodwill	33,963	26,291
Accumulated impairment of goodwill	(17,046)	(17,046)
Total	$ 16,917	$ 9,245