BUSINESS SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013 item	Mar. 31, 2012
BUSINESS SEGMENT INFORMATION
Number of operating segments	3
Segment Reporting Information, by Segment
Sales to external customers	$ 132,607	$ 157,167
Segment income	16,399	25,152
Photonics
Segment Reporting Information, by Segment
Sales to external customers	58,367	60,132
Segment income	12,566	12,280
Lasers
Segment Reporting Information, by Segment
Sales to external customers	38,885	49,227
Segment income	3,133	6,683
Optics
Segment Reporting Information, by Segment
Sales to external customers	35,355	47,808
Segment income	$ 700	$ 6,189