Per Share Amounts and Common Shares Outstanding (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Per Share Amounts and Common Shares Outstanding [Abstract]
Net income	$ 8,296	$ 6,962	$ 17,141	$ 10,075
Weighted-average shares outstanding, basic	14,039,000	13,993,000	13,914,000	14,059,000
Weighted-average shares, partially-paid share subscriptions	94,000	0	94,000	0
Basic weighted average shares	14,133,000	13,993,000	14,008,000	14,059,000
Incremental shares from assumed exercise of stock subscription purchase rights	17,000	0	6,000	0
Incremental shares from assumed exercise of stock options and awards	616,000	589,000	521,000	543,000
Diluted weighted-average shares	14,766,000	14,582,000	14,535,000	14,602,000
Net income per share, basic	$ 0.59	$ 0.50	$ 1.22	$ 0.72
Net income per share, diluted	$ 0.56	$ 0.48	$ 1.18	$ 0.69
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at January 1, 2012			13,845,635
Shares purchased			(486,832)
Shares sold			246,611
Stock Issued during period, stock subscription cash sales			76,465
Options and awards exercised			133,206
Change in shares outstanding			(30,550)
Shares outstanding at September 29, 2012	13,815,085		13,815,085
Employee and director options exercisable	818,400		818,400
Partially-paid subscriptions	561,374		561,374
Purchase rights outstanding	211,675		211,675