Preferred Stock - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended				12 Months Ended						1 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Aug. 25, 2011	Dec. 31, 2012 First quarter of 2013	Dec. 31, 2012 Fourth through ninth calendar quarters after closing Minimum	Dec. 31, 2012 Fourth through ninth calendar quarters after closing Maximum	Dec. 31, 2012 Tenth calendar quarter through four and one half years after issuance Minimum	Dec. 31, 2012 Tenth calendar quarter through four and one half years after issuance Maximum	Dec. 31, 2012 After four and one half years from issuance	Aug. 25, 2011 Senior Non-Cumulative Perpetual Preferred Stock, Series A	Dec. 31, 2012 Fixed Rate Cumulative Perpetual Preferred Stock, Series A
Class of Stock [Line Items]
Stock issued, shares												28,923
Proceeds from issuance of preferred stock												$ 28,923,000
Fund established under Small Business Jobs Act of 2010					30,000,000,000
Assets of qualified community banks under Small Business Jobs Act of 2010					10,000,000,000
Preferred stock, liquidation preference		$ 1,000	$ 1,000		$ 1,000
Preferred stock dividend payment term		The SBLF Preferred Stock is entitled to receive non-cumulative dividends, payable quarterly, on each January 1, April 1, July 1 and October 1, beginning October 1, 2011.
Preferred Stock, dividend rate		5.00%	5.00%	5.00%		5.00%	1.00%	5.00%	1.00%	7.00%	9.00%
Quarterly lending incentive fee											0.50%
Aggregate liquidation amount of preferred stock		25,000,000
Preferred stock redemption price percentage		100.00%
Preferred stock, shares redeemed													32,382
Warrant issued to purchase common stock		625,135
Common stock per share		$ 7.77
Warrant to purchase common stock, term		10 years
Repurchased price of warrant	$ 901,000
Dollar amount of Company's Tier 1 Capital as a percentage of Signing Date Tier 1 Capital, minimum percentage		90.00%
Tier 1 Dividend Threshold reduction for each one percent increase in QSBL		10.00%