Operating Income (Loss) from Continuing Operations by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2015	Sep. 26, 2014	Oct. 02, 2015	Sep. 26, 2014
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ 9,007	$ 6,822	$ 24,719	$ 17,370
Laser Products
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	10,145	9,857	28,586	23,828
Vision Technologies
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	(388)	(1,115)	(1,056)	(1,194)
Precision Motion
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	4,417	2,796	14,357	9,525
Unallocated Corporate and Shared Services
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ (5,167)	$ (4,716)	$ (17,168)	$ (14,789)