Borrowing - Additional Information (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Short-term Debt [Line Items]
Federal home loan bank additional borrowings capacity	$ 30,100,000	$ 25,100,000
Loans pledged as collateral	110,700,000	98,000,000
Cash management lines of credit, additional borrowings	15,000,000	15,000,000
Securities sold under agreements to repurchase	10,681,000	9,968,000
Security owned and pledged as collateral, fair value	$ 9,200,000	$ 15,200,000
Federal Home Loan one
Short-term Debt [Line Items]
Federal home loan bank, advances, branch of FHLB bank, interest rate, range from	3.08%
Federal home loan bank, advances, branch of FHLB bank, interest rate, range to	6.65%
Federal home loan bank, advances, branch of FHLB bank, weighted average interest rate	4.95%
Federal Home Loan two
Short-term Debt [Line Items]
Federal home loan bank, advances, branch of FHLB bank, interest rate, range from		3.08%
Federal home loan bank, advances, branch of FHLB bank, interest rate, range to		7.20%
Federal home loan bank, advances, branch of FHLB bank, weighted average interest rate		3.62%

Describes the weighted average interest rate applicable to the specific advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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- Definition

The carrying value as of the balance sheet date of securities that an institution sells and agrees to repurchase (the identical or substantially the same securities) as a seller-borrower at a specified date for a specified price, also known as a repurchase agreement, or repo. Most repos involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances, and negotiable certificates of deposit, are sometimes used in repos.

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- Definition

Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

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