Recorded Investment in Nonperforming Loans by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	$ 7,992	$ 7,401
Loans 90+ Days Past Due Still Accruing	99	363
Total Nonperforming Loans	9,569	11,515
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	2,698	2,281
Loans 90+ Days Past Due Still Accruing	67	143
Total Nonperforming Loans	7,117	7,308
Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	4	5
Loans 90+ Days Past Due Still Accruing	0	38
Total Nonperforming Loans	305	528
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	394	247
Loans 90+ Days Past Due Still Accruing	0	0
Total Nonperforming Loans	254	247
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	2,986	2,853
Loans 90+ Days Past Due Still Accruing	0	0
Total Nonperforming Loans	687	1,934
Commercial Business
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	1,809	1,928
Loans 90+ Days Past Due Still Accruing	0	0
Total Nonperforming Loans	25	256
Home Equity and Second Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	101	87
Loans 90+ Days Past Due Still Accruing	0	159
Total Nonperforming Loans	793	876
Other Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	0	0
Loans 90+ Days Past Due Still Accruing	32	23
Total Nonperforming Loans	388	366
Nonperforming Financing Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	8,091	7,764
Nonperforming Financing Receivable | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	2,765	2,424
Nonperforming Financing Receivable | Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	4	43
Nonperforming Financing Receivable | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	394	247
Nonperforming Financing Receivable | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	2,986	2,853
Nonperforming Financing Receivable | Commercial Business
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	1,809	1,928
Nonperforming Financing Receivable | Home Equity and Second Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	101	246
Nonperforming Financing Receivable | Other Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Nonperforming Loans	$ 32	$ 23