Net Income Per Share - Summary of Net Income Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 4,700	$ 3,876	$ 9,040	$ 7,590
Weighted-average common shares outstanding	17,578,543	17,353,359	17,558,380	17,332,898
Basic earnings per share	$ 0.27	$ 0.22	$ 0.51	$ 0.44
Common stock equivalents due to effect of stock options	195,000	169,000	209,000	161,000
Total weighted-average common shares and equivalents	17,773,656	17,521,793	17,766,951	17,493,942
Diluted earnings per share	$ 0.26	$ 0.22	$ 0.51	$ 0.43