Purchase and Assumption - Narrative (Detail) (USD $)	Feb. 10, 2012
Business Acquisition [Line Items]
Assets acquired, discount	$ 29,000,000
Difference between the purchase price of the assets acquired and the value of the liabilities assumed	17,200,000
Loans Receivable
Business Acquisition [Line Items]
Loans	86,300,000
Loan portfolio acquired, fair value discount	19,200,000
Performing portion of loan portfolio, fair value	76,500,000
Book value of assets and liabilities acquired
Business Acquisition [Line Items]
Assets Acquired	147,700,000
Cash and cash equivalents	11,900,000
Marketable securities	18,900,000
Federal Home Loan Bank stock	1,800,000
Loans	113,000,000
Premises and equipment	2,100,000
Liabilities absorbed	135,700,000
Customer deposits	125,900,000
Other Borrowed money	9,600,000
Other Liabilities	$ 402,000