Per Share Amounts and Common Shares Outstanding (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Per Share Amounts and Common Shares Outstanding [Abstract]
Net income	$ 9,416	$ 9,159	$ 8,845	$ 3,113
Basic weighted average shares	13,838,000	14,058,000	13,851,000	14,093,000
Exercise of stock options and awards	448,000	511,000	474,000	519,000
Diluted weighted-average shares	14,286,000	14,569,000	14,325,000	14,612,000
Net income per share, basic	$ 0.68	$ 0.65	$ 0.64	$ 0.22
Net income per share, diluted	$ 0.66	$ 0.63	$ 0.62	$ 0.21
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at January 1, 2012			13,845,635
Shares purchased			(394,390)
Shares sold			232,891
Options and awards exercised			129,081
Change in shares outstanding			(32,418)
Shares outstanding at June 30, 2012	13,813,217		13,813,217
Common shares, outstanding	13,813,217		13,813,217
Employee and director options exercisable	822,525		822,525