Note 7 - Loans and Allowance for Loan Losses (Detail) - Additional Information Regarding Impaired Loans (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Real Estate Construction And Land Development [Member]
Cash Basis Interest Income Recognized	$ 126	$ 169	$ 225	$ 406
Real Estate Mortgage Residential [Member]
Cash Basis Interest Income Recognized	166	454	398	814
Real Estate Mortgage Farmland And Other Commercial Enterprises [Member]
Cash Basis Interest Income Recognized	469	656	828	1,375
Commercial And Industrial [Member]
Cash Basis Interest Income Recognized		52	14	102
Consumer Secured [Member]
Cash Basis Interest Income Recognized			5	2
Consumer Unsecured [Member]
Cash Basis Interest Income Recognized	1		5
Total [Member]
Cash Basis Interest Income Recognized	762	1,331	1,475	2,699
Real Estate Construction And Land Development [Member]
Interest Income Recognized During Impairment	128	265	236	536
Real Estate Mortgage Residential [Member]
Interest Income Recognized During Impairment	159	469	401	851
Real Estate Mortgage Farmland And Other Commercial Enterprises [Member]
Interest Income Recognized During Impairment	498	657	1,001	1,478
Commercial And Industrial [Member]
Interest Income Recognized During Impairment		58	14	108
Consumer Secured [Member]
Interest Income Recognized During Impairment			5	3
Consumer Unsecured [Member]
Interest Income Recognized During Impairment	1		5
Total [Member]
Interest Income Recognized During Impairment	786	1,449	1,662	2,976
Real Estate Construction And Land Development [Member]
Average Of Individually Impaired Loans	41,044	54,107	38,297	56,041
Real Estate Mortgage Residential [Member]
Average Of Individually Impaired Loans	21,571	40,513	22,852	35,914
Real Estate Mortgage Farmland And Other Commercial Enterprises [Member]
Average Of Individually Impaired Loans	40,761	62,088	40,934	67,566
Commercial And Industrial [Member]
Average Of Individually Impaired Loans	301	4,553	533	4,434
Consumer Secured [Member]
Average Of Individually Impaired Loans	70	112	88	74
Consumer Unsecured [Member]
Average Of Individually Impaired Loans	186		189
Total [Member]
Average Of Individually Impaired Loans	$ 103,933	$ 161,373	$ 102,893	$ 164,029