Note 4 - Loans Leases Receivable - Loans by Internally Assigned Risk Rating (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Loans and leases	$ 3,723,630,222	$ 2,956,713,493
Commercial Portfolio Segment [Member]
Loans and leases	1,429,409,587	1,134,516,315
Commercial Portfolio Segment [Member] | Internally Assigned Risk Rating [Member]
Loans and leases	1,326,006,484	1,067,757,917
Commercial Portfolio Segment [Member] | Pass [Member]
Loans and leases	1,294,417,614	1,031,963,703
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans and leases	23,302,472	10,944,924
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans and leases	8,286,398	24,578,731
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans and leases		270,559
Commercial Real Estate Portfolio Segment [Member]
Loans and leases	1,766,110,775	1,303,491,882
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	500,653,731	332,742,477
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans and leases	236,787,308	186,402,404
Commercial Real Estate Portfolio Segment [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	1,028,669,736	784,347,000
Commercial Real Estate Portfolio Segment [Member] | Internally Assigned Risk Rating [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	500,653,731	332,742,477
Commercial Real Estate Portfolio Segment [Member] | Internally Assigned Risk Rating [Member] | Construction Loans [Member]
Loans and leases	236,787,308	186,402,404
Commercial Real Estate Portfolio Segment [Member] | Internally Assigned Risk Rating [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	1,028,669,736	784,347,000
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	487,948,800	318,293,608
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Construction Loans [Member]
Loans and leases	230,473,570	179,142,839
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	1,008,626,078	767,119,909
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	9,599,493	8,230,060
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Construction Loans [Member]
Loans and leases	3,847,691	1,780,000
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	5,308,625	10,068,870
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	3,105,438	6,218,809
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Construction Loans [Member]
Loans and leases	2,466,047	5,479,565
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and leases	14,735,033	7,158,221
Commercial and Commercial Real Estate Portfolio Segments [Member] | Internally Assigned Risk Rating [Member]
Loans and leases	$ 3,092,117,259	$ 2,371,249,799
As a % of Total	100.00%	100.00%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Pass [Member]
Loans and leases	$ 3,021,466,062	$ 2,296,520,059
As a % of Total	97.72%	96.85%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Special Mention [Member]
Loans and leases	$ 42,058,281	$ 31,023,854
As a % of Total	1.36%	1.31%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Substandard [Member]
Loans and leases	$ 28,592,916	$ 43,435,326
As a % of Total	0.92%	1.83%
Commercial and Commercial Real Estate Portfolio Segments [Member] | Doubtful [Member]
Loans and leases		$ 270,559
As a % of Total		0.01%