Note 3 - Loans Leases Receivable - Loans by Internally Assigned Risk Rating (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Loans	$ 2,545,699,171	$ 2,397,414,282
Commercial Portfolio Segment [Member]
Loans	942,538,419	827,637,263
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	904,511,211	796,568,451
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans	10,814,298	6,305,772
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans	27,212,910	24,763,040
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans
Commercial Real Estate Portfolio Segment [Member]
Loans	1,131,906,123	1,093,458,860
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans	317,225,055	332,387,621
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans	179,316,027	165,149,491
Commercial Real Estate Portfolio Segment [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans	635,365,041	595,921,748
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans	301,874,401	314,447,662
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Construction Loans [Member]
Loans	172,442,816	158,108,465
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans	622,588,629	582,854,048
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans	10,448,915	7,559,380
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Construction Loans [Member]
Loans	1,780,000	1,780,000
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans	4,693,909	4,437,122
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans	4,901,739	10,380,369
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Construction Loans [Member]
Loans	5,093,211	5,261,026
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans	8,082,503	8,630,578
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans		210
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Construction Loans [Member]
Loans
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans
Commercial and Commercial Real Estate Portfolio Segments [Member]
Loans	$ 2,074,444,542	$ 1,921,096,123
As a % of Total	100.00%	100.00%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Pass [Member]
Loans	$ 2,001,417,057	$ 1,851,978,626
As a % of Total	96.48%	96.40%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Special Mention [Member]
Loans	$ 27,737,122	$ 20,082,274
As a % of Total	1.34%	1.05%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Substandard [Member]
Loans	$ 45,290,363	$ 49,035,013
As a % of Total	2.18%	2.55%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Doubtful [Member]
Loans		$ 210
As a % of Total	0.00%	0.00%