Note 3 - Loans/Leases Receivable (Details) - Composition of the Loan/Lease Portfolio (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 1,647,453,571		$ 1,623,338,950
Plus deferred loan/lease orgination costs, net of fees	6,997,665		6,664,120
Gross loans/leases receivable	1,654,451,236		1,630,003,070
Less allowance for estimated losses on loans/leases	(23,883,273)		(23,074,365)		(22,653,270)	(21,448,048)
Net loans/leases receivable	1,630,567,963		1,606,928,705
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	534,885,417		523,927,140
Less allowance for estimated losses on loans/leases	(9,093,649)		(8,750,317)		(6,647,658)	(5,648,774)
Owner-Occupied Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	263,646,328		260,069,080
Commercial Construction, Land Development, and Other Land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	60,040,330		68,118,989
Other Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	385,995,048		373,952,353
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	709,681,706		702,140,422
Less allowance for estimated losses on loans/leases	(8,838,204)		(8,353,386)		(10,587,657)	(10,705,434)
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	167,244,011	[1]	166,032,416	[1]
Plus deferred loan/lease orgination costs, net of fees	6,654,946	[1]	6,639,244	[1]
Gross loans/leases receivable	173,898,957	[1]	172,671,660	[1]
Less allowance for estimated losses on loans/leases	(3,310,973)	[1]	(3,442,915)	[1]	(2,820,239)	(2,517,217)
Net loans/leases receivable	170,587,984	[1]	169,228,745	[1]
Net minimum lease payments to be received	189,170,774	[1]	188,181,432	[1]
Estimated unguaranteed residual values of leased assets	1,481,232	[1]	1,488,342	[1]
Unearned lease/residual income	(23,407,995)	[1]	(23,637,358)	[1]
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	163,739,861	[2]	158,632,492	[2]
Less allowance for estimated losses on loans/leases	(1,597,754)		(1,525,952)		(1,388,885)	(1,395,849)
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	71,902,576		72,606,480
Less allowance for estimated losses on loans/leases	$ (1,042,693)		$ (1,001,795)		$ (1,208,831)	$ (1,180,774)

[1] Management performs an evaluation of the estimated unguaranteed residual values of leased assets on an annual basis, at a minimum. The evaluation consists of discussions with reputable and current vendors and management's expertise and understanding of the current states of particular industries to determine informal valuations of the equipment. As necessary and where available, management will utilize valuations by independent appraisers. The large majority of leases with residual values contain a lease options rider which requires the lessee to pay the residual value directly, finance the payment of the residual value, or extend the lease term to pay the residual value. In these cases, the residual value is protected and the risk of loss is minimal. There were no losses related to residual values for the three months ended March 31, 2015 and 2014.

[2] Includes residential real estate loans held for sale totaling $789,000 and $553,000 as of March 31, 2015, and December 31, 2014, respectively.