Allowance for Loan Losses - Summary of Performing and Nonperforming Loans by Class (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 312,148	$ 329,183	[1]
Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	305,946	319,703
Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	6,202	9,480
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	46,001	41,390
Commercial [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	45,694	40,953
Commercial [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	307	437
Real Estate - Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	96,745	103,304
Real Estate - Commercial [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	94,486	100,272
Real Estate - Commercial [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,259	3,032
Other Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	19,435	25,052
Other Real Estate Construction [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	17,854	22,107
Other Real Estate Construction [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,581	2,945
Real Estate 1-4 Family Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,610	3,080
Real Estate 1-4 Family Construction [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,610	3,080
Real Estate 1-4 Family Construction [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans
Real Estate - Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	90,777	94,032
Real Estate - Residential [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	88,935	91,524
Real Estate - Residential [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,842	2,507
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	46,133	48,517
Home Equity [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	45,920	47,960
Home Equity [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	213	558
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	8,757	12,986
Consumer Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	8,757	12,985
Consumer Loans [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans		1
Other Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	690	822
Other Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	690	822
Other Loans [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans

[1] Derived from audited consolidated financial statements