Aging of Recorded Investment in Loans by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	$ 4,872	$ 7,443
60-89 Days Past Due	1,237	1,220
Over 90 Days Past Due	2,580	2,852
Total Past Due	8,689	11,515
Current	271,061	269,841
Recorded investment in loans	279,750	281,356
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	3,814	5,205
60-89 Days Past Due	961	1,068
Over 90 Days Past Due	871	1,035
Total Past Due	5,646	7,308
Current	106,589	109,560
Recorded investment in loans	112,235	116,868
Land
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	172	442
60-89 Days Past Due	0	43
Over 90 Days Past Due	37	43
Total Past Due	209	528
Current	9,617	9,444
Recorded investment in loans	9,826	9,972
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Over 90 Days Past Due	265	247
Total Past Due	265	247
Current	7,702	6,732
Recorded investment in loans	7,967	6,979
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	260	676
60-89 Days Past Due	128	0
Over 90 Days Past Due	1,239	1,258
Total Past Due	1,627	1,934
Current	58,574	55,906
Recorded investment in loans	60,201	57,840
Commercial Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	20	256
60-89 Days Past Due	18	0
Over 90 Days Past Due	0	0
Total Past Due	38	256
Current	19,992	20,520
Recorded investment in loans	20,030	20,776
Home Equity and Second Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	368	558
60-89 Days Past Due	40	72
Over 90 Days Past Due	152	246
Total Past Due	560	876
Current	37,784	38,011
Recorded investment in loans	38,344	38,887
Other Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	238	306
60-89 Days Past Due	90	37
Over 90 Days Past Due	16	23
Total Past Due	344	366
Current	30,803	29,668
Recorded investment in loans	$ 31,147	$ 30,034