BUSINESS SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013 item	Jun. 30, 2012
BUSINESS SEGMENT INFORMATION
Number of operating segments			3
Segment Reporting Information, by Segment
Sales to external customers	$ 134,234	$ 153,655	$ 266,841	$ 310,822
Segment income	16,867	23,842	33,266	48,994
Photonics
Segment Reporting Information, by Segment
Sales to external customers	55,449	60,497	113,816	120,629
Segment income	10,767	13,488	23,333	25,768
Lasers
Segment Reporting Information, by Segment
Sales to external customers	39,423	44,734	78,308	93,961
Segment income	4,225	2,905	7,358	9,588
Optics
Segment Reporting Information, by Segment
Sales to external customers	39,362	48,424	74,717	96,232
Segment income	$ 1,875	$ 7,449	$ 2,575	$ 13,638