Net Income Per Share - Net Income Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Net Income Per Share Basic And Diluted [Abstract]
Net income	$ 2,580	$ 2,307	$ 7,312	$ 6,959	$ 9,351
Weighted average common shares outstanding	14,433,695	14,311,900	14,469,077	14,297,888
Dilutive effect of common stock options, warrants and restricted stock	310,463	404,600	304,186	372,109
Shares used in computation of net income per common share - diluted	14,744,158	14,716,500	14,773,263	14,669,997
Net income per common share - basic	$ 0.18	$ 0.16	$ 0.51	$ 0.49
Net income per common share - diluted	$ 0.18	$ 0.16	$ 0.49	$ 0.47