Nature of Operations and Summary of Significant Accounting Policies - Summary of Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Basic earnings per share
Net income	$ 4,115	$ 4,785	$ 5,665	$ 5,311	$ 5,170	$ 4,850	$ 4,910	$ 4,613	$ 19,876	$ 19,543	$ 12,797
Less: Preferred stock dividends and accretion of discount									370	481	1,325
Net income available to common shareholders	4,052	4,719	5,569	5,165	5,014	4,787	4,804	4,457	19,506	19,062	11,472
Weighted average common shares outstanding	8,623,360	8,618,969	8,617,466	8,617,466	8,617,466	8,503,475	7,434,537	7,422,860	8,619,330	7,974,241	7,407,258
Basic Earnings Per Share	$ 0.47	$ 0.55	$ 0.65	$ 0.60	$ 0.58	$ 0.56	$ 0.65	$ 0.60	$ 2.26	$ 2.39	$ 1.55
Diluted earnings per share
Net income available to common shareholders									$ 19,506	$ 19,062	$ 11,472
Weighted average common shares outstanding	8,623,360	8,618,969	8,617,466	8,617,466	8,617,466	8,503,475	7,434,537	7,422,860	8,619,330	7,974,241	7,407,258
Effect of dilutive securities:
Warrants									303,970	245,514	161,922
Weighted average shares outstanding	9,020,289	9,019,211	8,974,103	8,980,655	8,964,315	8,838,659	7,728,519	7,598,490	9,000,963	8,271,177	7,588,394
Diluted Earnings Per Share	$ 0.45	$ 0.52	$ 0.62	$ 0.58	$ 0.56	$ 0.54	$ 0.62	$ 0.59	$ 2.17	$ 2.30	$ 1.51
Restricted Stock [Member]
Effect of dilutive securities:
Effect of dilutive securities									40,160	23,181	4,361
Stock Options [Member]
Effect of dilutive securities:
Effect of dilutive securities									37,503	28,241	14,853