Segments (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012 Segment	Jul. 03, 2011
Segments (Textual) [Abstract]
Segment operating earnings	$ 9,544	$ 5,221	$ 11,476	$ 10,980
Insurance recovery for property damage - casualties			1,769
Segments (Additional Textual) [Abstract]
Number of Reportable Segments			2
EMS [Member]
Segments (Textual) [Abstract]
Segment operating earnings	4,180	370	3,092	373
Insurance recovery for property damage - casualties			$ 1,769