Significant Accounting Policies, Recent Accounting Pronouncements, Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	6 Months Ended
	Aug. 31, 2011	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Accounting Policies [Line Items]
Commitment to extend credit		$ 114,000,000
Commitment related to standby letters of credit		1,000,000
Unrealized fair value gain from interest rate contracts and TBA security hedges		327,000	726,000
Punitive damages	900,000
Attorney fees and cost	540,000	339,000
Required ratio of adjusted tangible shareholders' equity to tangible assets by January 31, 2011				9.00%
Maximum possible reduction in tangible assets, in percent				15.00%
Proceed from sale of series B preferred stock	11,200,000
Series B Preferred stock, dividend rate percentage	8.40%
Ratio of adjusted tangible shareholders' equity to tangible assets	9.00%	10.75%
Compensatory damages awarded to plaintiff before the case went to the jury for a decision
Significant Accounting Policies [Line Items]
Amount of compensatory damage awarded to plaintiff	100,000
Jury imposed compensatory damages
Significant Accounting Policies [Line Items]
Amount of compensatory damage awarded to plaintiff	150,000
Interest Rate Contracts and TBA security hedges
Significant Accounting Policies [Line Items]
Unrealized fair value gain from interest rate contracts and TBA security hedges		$ 1,500,000