Carrying Value and Estimated Fair Value of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Carrying (Reported) Amount, Fair Value Disclosure
Financial assets:
Cash and cash equivalents	$ 29,038	$ 23,211
Securities available for sale	116,586	122,973
Securities held to maturity	11	12
Loans held for sale	4,918	3,609
Loans, net	275,674	280,407
FHLB stock	2,820	2,820
Accrued interest receivable	1,722	1,757
Financial liabilities:
Deposits	383,921	384,343
Retail repurchase agreements	10,579	14,092
Advances from FHLB	5,100	5,100
Accrued interest payable	260	290
Estimate of Fair Value, Fair Value Disclosure
Financial assets:
Cash and cash equivalents	29,038	23,211
Securities available for sale	116,586	122,973
Securities held to maturity	11	12
Loans held for sale	5,008	3,705
Loans, net	279,996	287,609
FHLB stock	2,820	2,820
Accrued interest receivable	1,722	1,757
Financial liabilities:
Deposits	384,656	385,212
Retail repurchase agreements	10,579	14,092
Advances from FHLB	5,100	5,100
Accrued interest payable	260	290
Level 1
Financial assets:
Cash and cash equivalents	29,038	23,211
Securities available for sale	4,341	4,237
Securities held to maturity	0	0
Loans held for sale	0	0
Loans, net	0	0
FHLB stock	0	0
Accrued interest receivable	0	0
Financial liabilities:
Deposits	0	0
Retail repurchase agreements	0	0
Advances from FHLB	0	0
Accrued interest payable	0	0
Level 2
Financial assets:
Cash and cash equivalents	0	0
Securities available for sale	112,245	118,736
Securities held to maturity	11	12
Loans held for sale	5,008	3,705
Loans, net	0	0
FHLB stock	2,820	2,820
Accrued interest receivable	1,722	1,757
Financial liabilities:
Deposits	0	0
Retail repurchase agreements	10,579	14,092
Advances from FHLB	5,100	5,100
Accrued interest payable	260	290
Level 3
Financial assets:
Cash and cash equivalents	0	0
Securities available for sale	0	0
Securities held to maturity	0	0
Loans held for sale	0	0
Loans, net	279,996	287,609
FHLB stock	0	0
Accrued interest receivable	0	0
Financial liabilities:
Deposits	384,656	385,212
Retail repurchase agreements	0	0
Advances from FHLB	0	0
Accrued interest payable	$ 0	$ 0