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Note 3 - Loans Leases Receivable - Composition of the Loan Lease Portfolio (Details) - USD ($)	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Gross loans/leases receivable	$ 3,114,792,423		$ 2,964,485,400
Less allowance	(37,545,076)	$ (36,532,602)	(34,355,728)	$ (33,356,632)	$ (32,059,150)	$ (30,757,448)
Net loans/leases receivable	3,077,247,347		2,930,129,672
Plus deferred loan/lease origination costs, net of fees	8,890,965		7,771,907
Loans and Leases Receivable, Net of Deferred Income	3,105,901,458		2,956,713,493
Commercial Portfolio Segment [Member]
Less allowance	(15,233,871)	(15,065,245)	(14,323,036)	(14,207,733)	(12,954,090)	(12,545,110)
Loans and Leases Receivable, Net of Deferred Income	1,273,000,094		1,134,516,315
Commercial Real Estate Portfolio Segment [Member]
Less allowance	(15,819,040)	(14,938,020)	(13,962,688)	(12,999,233)	(12,643,266)	(11,670,609)
Loans and Leases Receivable, Net of Deferred Income	1,349,318,914		1,303,491,882
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Loans and Leases Receivable, Net of Deferred Income	349,007,830		332,742,477
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Net of Deferred Income	162,644,566		186,402,404
Commercial Real Estate Portfolio Segment [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loans and Leases Receivable, Net of Deferred Income	837,666,518		784,347,000
Finance Leases Portfolio Segment [Member]
Net minimum lease payments to be received	147,388,211		156,583,887
Estimated unguaranteed residual values of leased assets	929,932		929,932
Unearned lease/residual income	(15,121,530)		(16,065,587)
Gross loans/leases receivable	137,356,324		146,072,259
Less allowance	(2,724,355)	(2,730,301)	(2,382,098)	(2,638,301)	(2,978,260)	(3,111,898)
Net loans/leases receivable	134,631,969		143,690,161
Plus deferred loan/lease origination costs, net of fees	4,159,711		4,624,027
Loans and Leases Receivable, Net of Deferred Income	133,196,613		141,448,232
Residential Portfolio Segment [Member]
Less allowance	(2,433,102)	(2,375,219)	(2,466,431)	(2,430,454)	(2,375,864)	(2,342,344)
Loans and Leases Receivable, Net of Deferred Income	257,433,713		258,646,265
Consumer Portfolio Segment [Member]
Less allowance	(1,334,708)	$ (1,423,817)	(1,221,475)	$ (1,080,911)	$ (1,107,670)	$ (1,087,487)
Loans and Leases Receivable, Net of Deferred Income	$ 92,952,124		$ 118,610,799