Loans (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Receivables [Line Items]
Loans, gross	$ 293,630		$ 289,247
Deferred loan origination fees, net	255		202
Undisbursed portion of loans in process	(5,890)		(4,306)
Allowance for loan losses	(4,835)	(4,792)	(4,736)	(4,432)	(4,228)	(4,182)
Loans, net	283,160		280,407
Real Estate Portfolio Segment | Residential
Receivables [Line Items]
Loans, gross	107,773		108,097
Real Estate Portfolio Segment | Land
Receivables [Line Items]
Loans, gross	10,155		9,607
Real Estate Portfolio Segment | Residential Construction
Receivables [Line Items]
Loans, gross	14,823		12,753
Real Estate Portfolio Segment | Commercial Real Estate
Receivables [Line Items]
Loans, gross	70,306		68,731
Real Estate Portfolio Segment | Real Estate Construction
Receivables [Line Items]
Loans, gross	3,135		3,299
Commercial Business
Receivables [Line Items]
Loans, gross	21,395		18,612
Deferred loan origination fees, net	(9)		(10)
Allowance for loan losses	(1,260)	(1,226)	(1,223)	(1,154)	(1,175)	(1,160)
Other Consumer
Receivables [Line Items]
Deferred loan origination fees, net	0		0
Allowance for loan losses	(352)	(330)	(291)	(297)	(284)	(399)
Other Consumer | Home Equity and Second Mortgage
Receivables [Line Items]
Loans, gross	33,821		36,962
Other Consumer | Automobile Loan
Receivables [Line Items]
Loans, gross	23,113		21,922
Other Consumer | Loans Secured by Savings Accounts
Receivables [Line Items]
Loans, gross	1,042		770
Other Consumer | Unsecured Loan
Receivables [Line Items]
Loans, gross	3,134		3,191
Other Consumer | Other Consumer Loan
Receivables [Line Items]
Loans, gross	$ 4,933		$ 5,303