Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Carrying (Reported) Amount, Fair Value Disclosure
Financial assets:
Cash and cash equivalents	$ 22,695	$ 18,923
Securities available for sale	123,375	111,440
Securities held to maturity	14	16
Loans held for sale	2,306	2,909
Loans, net	280,967	276,047
Federal Home Loan Bank stock	2,820	2,820
Accrued interest receivable	1,782	1,801
Financial liabilities:
Deposits	384,067	364,374
Retail repurchase agreements	9,112	9,125
Advances from Federal Home Loan Bank	10,100	12,350
Accrued interest payable	320	413
Off-balance-sheet financial instruments:
Asset related to commitments to extend credit	0	0
Estimate of Fair Value, Fair Value Disclosure
Financial assets:
Cash and cash equivalents	22,695	18,923
Securities available for sale	123,375	111,440
Securities held to maturity	14	16
Loans held for sale	2,364	2,966
Loans, net	285,564	287,624
Federal Home Loan Bank stock	2,820	2,820
Accrued interest receivable	1,782	1,801
Financial liabilities:
Deposits	385,147	367,359
Retail repurchase agreements	9,112	9,125
Advances from Federal Home Loan Bank	10,100	12,840
Accrued interest payable	320	413
Off-balance-sheet financial instruments:
Asset related to commitments to extend credit	$ 0	$ 48