Age Analysis of Past Due Loans, Segregated 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]
Total Gross Loans	$ 378,442	$ 389,466
Real Estate Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	295,469	312,766
Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	11,280	13,480
Real Estate Loans | Farmland
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	32,986	35,912
Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	119,297	133,987
Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	131,906	129,387
Business Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	40,014	38,160
Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	38,499	36,581
Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	1,515	1,579
Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	42,959	38,540
Consumer Loans | Credit Cards
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	976	995
Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	41,983	37,545
Class of Financing Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	10,078	13,991
Loans 90 or more Days Past Due	6,010	6,752
Total Past Due Loans	16,088	20,743
Current Loans	362,354	368,723
Total Gross Loans	378,442	389,466
Accruing Loans 90 or more Days Past Due	120	269
Class of Financing Receivable | Real Estate Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	8,284	11,806
Loans 90 or more Days Past Due	5,916	6,378
Total Past Due Loans	14,200	18,184
Current Loans	281,269	294,582
Total Gross Loans	295,469	312,766
Accruing Loans 90 or more Days Past Due	49	228
Class of Financing Receivable | Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	77	30
Loans 90 or more Days Past Due		562
Total Past Due Loans	77	592
Current Loans	11,203	12,888
Total Gross Loans	11,280	13,480
Accruing Loans 90 or more Days Past Due		39
Class of Financing Receivable | Real Estate Loans | Farmland
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	552	1,061
Loans 90 or more Days Past Due	347	139
Total Past Due Loans	899	1,200
Current Loans	32,087	34,712
Total Gross Loans	32,986	35,912
Class of Financing Receivable | Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	4,625	5,774
Loans 90 or more Days Past Due	897	822
Total Past Due Loans	5,522	6,596
Current Loans	113,775	127,391
Total Gross Loans	119,297	133,987
Accruing Loans 90 or more Days Past Due	49	80
Class of Financing Receivable | Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	3,030	4,941
Loans 90 or more Days Past Due	4,672	4,855
Total Past Due Loans	7,702	9,796
Current Loans	124,204	119,591
Total Gross Loans	131,906	129,387
Accruing Loans 90 or more Days Past Due		109
Class of Financing Receivable | Business Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	443	307
Loans 90 or more Days Past Due	8	105
Total Past Due Loans	451	412
Current Loans	51,866	37,748
Total Gross Loans	52,317	38,160
Class of Financing Receivable | Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	420	294
Loans 90 or more Days Past Due	8	99
Total Past Due Loans	428	393
Current Loans	50,374	36,188
Total Gross Loans	50,802	36,581
Class of Financing Receivable | Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	23	13
Loans 90 or more Days Past Due		6
Total Past Due Loans	23	19
Current Loans	1,492	1,560
Total Gross Loans	1,515	1,579
Class of Financing Receivable | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	1,351	1,878
Loans 90 or more Days Past Due	86	269
Total Past Due Loans	1,437	2,147
Current Loans	29,219	36,393
Total Gross Loans	30,656	38,540
Accruing Loans 90 or more Days Past Due	71	41
Class of Financing Receivable | Consumer Loans | Credit Cards
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	51	20
Loans 90 or more Days Past Due	28	17
Total Past Due Loans	79	37
Current Loans	897	958
Total Gross Loans	976	995
Accruing Loans 90 or more Days Past Due	28	17
Class of Financing Receivable | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-89 Days Past Due	1,300	1,858
Loans 90 or more Days Past Due	58	252
Total Past Due Loans	1,358	2,110
Current Loans	28,322	35,435
Total Gross Loans	29,680	37,545
Accruing Loans 90 or more Days Past Due	$ 43	$ 24