Detailed Amount of Gross Loans by Loan Grade and Class (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 378,442	$ 389,466
Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	295,469	312,766
Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	11,280	13,480
Real Estate Loans | Farmland
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	32,986	35,912
Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	119,297	133,987
Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	131,906	129,387
Business Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	40,014	38,160
Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	38,499	36,581
Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,515	1,579
Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	42,959	38,540
Consumer Loans | Credit Cards
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	976	995
Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	41,983	37,545
Satisfactory 1, 2, 3, 4
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	324,869	331,052
Satisfactory 1, 2, 3, 4 | Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	246,594	264,764
Satisfactory 1, 2, 3, 4 | Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	8,946	9,647
Satisfactory 1, 2, 3, 4 | Real Estate Loans | Farmland
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	28,574	31,405
Satisfactory 1, 2, 3, 4 | Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	100,826	115,365
Satisfactory 1, 2, 3, 4 | Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	108,248	108,347
Satisfactory 1, 2, 3, 4 | Business Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	38,119	29,451
Satisfactory 1, 2, 3, 4 | Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	36,686	27,970
Satisfactory 1, 2, 3, 4 | Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,433	1,481
Satisfactory 1, 2, 3, 4 | Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	41,476	36,837
Satisfactory 1, 2, 3, 4 | Consumer Loans | Credit Cards
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	948	978
Satisfactory 1, 2, 3, 4 | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	40,528	35,859
Special Mention 5,6
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	18,802	26,350
Special Mention 5,6 | Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	17,351	18,305
Special Mention 5,6 | Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,906	2,290
Special Mention 5,6 | Real Estate Loans | Farmland
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	2,797	3,043
Special Mention 5,6 | Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	5,783	5,784
Special Mention 5,6 | Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	6,865	7,188
Special Mention 5,6 | Business Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,137	7,720
Special Mention 5,6 | Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,108	7,712
Special Mention 5,6 | Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	29	8
Special Mention 5,6 | Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	314	325
Special Mention 5,6 | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	314	325
Substandard 7
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	33,392	31,882
Substandard 7 | Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	31,524	29,608
Substandard 7 | Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	428	1,481
Substandard 7 | Real Estate Loans | Farmland
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,615	1,464
Substandard 7 | Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	12,688	12,811
Substandard 7 | Real Estate Loans | Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	16,793	13,852
Substandard 7 | Business Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	728	953
Substandard 7 | Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	675	863
Substandard 7 | Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	53	90
Substandard 7 | Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,140	1,321
Substandard 7 | Consumer Loans | Credit Cards
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	28	17
Substandard 7 | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,112	1,304
Doubtful 8
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	59	116
Doubtful 8 | Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		27
Doubtful 8 | Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		27
Doubtful 8 | Business Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	30	36
Doubtful 8 | Business Loans | Commercial and Industrial Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	30	36
Doubtful 8 | Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	29	53
Doubtful 8 | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	29	53
Loss 9
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		66
Loss 9 | Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		62
Loss 9 | Real Estate Loans | Land Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		62
Loss 9 | Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		4
Loss 9 | Consumer Loans | Other Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Total gross loans		$ 4