Weighted Average Number of Shares Outstanding Used to Compute Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Weighted Average Number of Shares Outstanding [Line Items]
Net earnings	$ 5,504	$ 5,507	$ 9,211	$ 7,897
Weighted-Average Number of Common Shares Outstanding
Basic weighted-average common shares outstanding	10,648	10,582	10,624	10,565
Dilutive potential common shares	142		107
Diluted weighted-average common shares outstanding	10,790	10,582	10,731	10,565
Basic	$ 0.52	$ 0.52	$ 0.87	$ 0.75
Diluted	$ 0.51	$ 0.52	$ 0.86	$ 0.75