Note 3 - Loans/Leases Receivable (Detail) - Aging of the Loan/Lease Portfolio (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current	$ 1,263,095,879	$ 1,257,131,874
30-59 Days Past Due	4,847,540	7,387,450
60-89 Days Past Due	2,268,068	1,599,934
Accruing Past Due 90 Days or More	519	159,481
Nonacrrual Loans/Loans	18,040,278	17,932,495
Total	1,288,252,284	1,284,211,234
Current as a percentage of total loan/lease portfolio	98.05%	97.89%
30-59 Days Past Due as a percentage of total loan/lease portfolio	0.38%	0.58%
60-89 Days Past Due as a percentage of total loan/lease portfolio	0.18%	0.12%
Accruing Past Due 90 Days or More as a percentage of total loan/lease portfolio	0.00%	0.01%
Nonacrrual Loans/Loans as a percentage of total loan/lease portfolio	1.40%	1.40%
Total as a percentage of total loan/lease portfolio	100.00%	100.00%
Commercial and Industrial [Member]
Current	396,879,932	388,825,307
30-59 Days Past Due	182,414	3,724,506
60-89 Days Past Due	89,771	9,940
Accruing Past Due 90 Days or More		120,000
Nonacrrual Loans/Loans	970,123	1,564,499
Total	398,122,240	394,244,252
Owner-occupied commercial real estate [Member]
Current	210,645,611	204,141,070
30-59 Days Past Due	1,037,596	142,993
60-89 Days Past Due	0	0
Accruing Past Due 90 Days or More	0	0
Nonacrrual Loans/Loans	618,332	627,245
Total	212,301,539	204,911,308
Commercial construction, land development, and other land [Member]
Current	43,557,385	42,180,819
60-89 Days Past Due	337,500	0
Accruing Past Due 90 Days or More		0
Nonacrrual Loans/Loans	2,554,275	2,781,562
Total	46,449,160	44,962,381
Other commercial real estate [Member]
Current	326,644,315	332,644,532
30-59 Days Past Due	1,097,226	86,986
60-89 Days Past Due	1,403,803	1,111,856
Accruing Past Due 90 Days or More	0	0
Nonacrrual Loans/Loans	10,737,575	10,262,176
Total	339,882,919	344,105,550
Leases receivable [Member]
Current	107,181,954	101,635,084
30-59 Days Past Due	1,204,354	877,210
60-89 Days Past Due	57,070	174,560
Accruing Past Due 90 Days or More	0	0
Nonacrrual Loans/Loans	1,210,936	998,802
Total	109,654,314	103,685,656
Residential Real Estate [Member]
Current	113,860,680	111,993,859
30-59 Days Past Due	751,593	2,254,730
60-89 Days Past Due		283,466
Accruing Past Due 90 Days or More	0	0
Nonacrrual Loans/Loans	935,936	1,049,518
Total	115,548,209	115,581,573
Installment and Other Consumer [Member]
Current	64,326,002	75,711,203
30-59 Days Past Due	574,357	301,025
60-89 Days Past Due	379,924	20,112
Accruing Past Due 90 Days or More	519	39,481
Nonacrrual Loans/Loans	1,013,101	648,693
Total	$ 66,293,903	$ 76,720,514