Segments (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Reconciling information between reportable segments' operating earnings before income taxes
Total segment operating earnings	$ 9,821,000	$ 9,544,000	$ 13,605,000	$ 11,476,000
Interest expense	(1,079,000)	(626,000)	(1,994,000)	(1,285,000)
Interest income	446,000	467,000	859,000	916,000
Other expense	(310,000)	(1,041,000)	(12,000)	(466,000)
Earnings before income taxes	783,000	4,513,000	3,541,000	6,810,000
Components and Sensors [Member]
Reconciling information between reportable segments' operating earnings before income taxes
Total segment operating earnings	11,367,000	5,364,000	15,770,000	8,384,000
Restructuring and restructuring-related charges	(7,667,000)	(1,239,000)	(7,894,000)	(1,239,000)
EMS [Member]
Reconciling information between reportable segments' operating earnings before income taxes
Total segment operating earnings	(1,546,000)	4,180,000	(2,165,000)	3,092,000
Restructuring and restructuring-related charges	$ (428,000)	$ (2,592,000)	$ (1,023,000)	$ (2,592,000)