Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Calculation of segment income
Sales to external customers	$ 153,655	$ 130,132	$ 310,822	$ 258,543
Segment, Continuing Operations [Member]
Calculation of segment income
Segment income	23,770	24,791	48,686	49,260
Photonics and Precision Technologies [Member]
Calculation of segment income
Sales to external customers	82,858	85,415	161,912	167,579
Segment income	18,987	20,746	34,982	40,411
Lasers [Member]
Calculation of segment income
Sales to external customers	44,734	44,717	93,961	90,964
Segment income	2,878	4,045	9,534	8,849
Ophir [Member]
Calculation of segment income
Sales to external customers	26,063		54,949
Segment income	$ 1,905		$ 4,170