Impaired Loans, Segregated by Class of Loans (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 14,855,000	$ 13,592,000
Recorded Investment With No Allowance	4,429,000	2,513,000
Recorded Investment With Allowance	10,426,594	11,079,526
Total Recorded Investment	14,855,000	13,592,000
Related Allowance	2,636,352	2,296,603
Average Recorded Investment	14,281,000	14,007,000
Real Estate Loans
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	12,644,000	11,248,000
Recorded Investment With No Allowance	4,302,000	2,275,000
Recorded Investment With Allowance	8,342,000	8,973,000
Total Recorded Investment	12,644,000	11,248,000
Related Allowance	1,076,000	1,225,000
Average Recorded Investment	12,044,000	12,644,000
Real Estate Loans | Land Development and Construction
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	130,000	136,000
Recorded Investment With No Allowance	24,000	25,000
Recorded Investment With Allowance	106,000	111,000
Total Recorded Investment	130,000	136,000
Related Allowance	103,000	103,000
Average Recorded Investment	130,000	278,000
Real Estate Loans | Farmland
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	281,000	352,000
Recorded Investment With No Allowance	153,000	220,000
Recorded Investment With Allowance	128,000	132,000
Total Recorded Investment	281,000	352,000
Related Allowance	24,000	24,000
Average Recorded Investment	339,000	720,000
Real Estate Loans | 1-4 Family Mortgages
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,672,000	1,866,000
Recorded Investment With No Allowance	1,328,000	1,054,000
Recorded Investment With Allowance	344,000	812,000
Total Recorded Investment	1,672,000	1,866,000
Related Allowance	53,000	202,000
Average Recorded Investment	1,653,000	2,111,000
Real Estate Loans | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	10,561,000	8,894,000
Recorded Investment With No Allowance	2,797,000	976,000
Recorded Investment With Allowance	7,764,000	7,918,000
Total Recorded Investment	10,561,000	8,894,000
Related Allowance	896,000	896,000
Average Recorded Investment	9,922,000	9,535,000
Business Loans
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,131,000	2,224,000
Recorded Investment With No Allowance	47,000	118,000
Recorded Investment With Allowance	2,084,000	2,106,000
Total Recorded Investment	2,131,000	2,224,000
Related Allowance	1,560,000	1,072,000
Average Recorded Investment	2,136,000	1,197,000
Business Loans | Commercial and Industrial Loans
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,131,000	2,224,000
Recorded Investment With No Allowance	47,000	118,000
Recorded Investment With Allowance	2,084,000	2,106,000
Total Recorded Investment	2,131,000	2,224,000
Related Allowance	1,560,000	1,072,000
Average Recorded Investment	2,136,000	1,195,000
Business Loans | Farm Production and Other Farm Loans
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		2,000
Consumer Loans
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	80,000	120,000
Recorded Investment With No Allowance	80,000	120,000
Total Recorded Investment	80,000	120,000
Average Recorded Investment	100,000	166,000
Consumer Loans | Other Consumer Loans
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	80,000	120,000
Recorded Investment With No Allowance	80,000	120,000
Total Recorded Investment	80,000	120,000
Average Recorded Investment	$ 100,000	$ 166,000