Summary of Significant Accounting Policies - 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		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Accounting Policies [Abstract]
Net earnings	$ 2,622	$ 4,636	$ 13,723	$ 13,847
Weighted-average number of common shares outstanding
Basic weighted-average common shares outstanding	10,921	10,722	10,902	10,657
Dilutive potential common shares	229	195	300	128
Diluted weighted-average common shares outstanding	11,150	10,917	11,202	10,785
Earnings Per Share
Basic (in dollars per share)	$ 0.24	$ 0.43	$ 1.26	$ 1.30
Diluted (in dollars per share)	$ 0.24	$ 0.42	$ 1.23	$ 1.28