Note 3 - Loans/Leases Receivable (Detail) - Composition of the Loan/Lease Portfolio (USD $)	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2011
Loans and Leases	$ 1,291,795,511		$ 1,287,387,639
Less allowance for estimated losses on loans/leases	(20,769,462)		(19,925,204)		(19,006,644)	(18,789,262)
Loans/leases net of allowance for estimated losses	1,271,026,049		1,267,462,435
Commercial and Industrial [Member]
Loans and Leases	398,122,240		394,244,252
Less allowance for estimated losses on loans/leases	(4,466,264)		(4,531,545)		(4,585,467)	(4,878,006)
Owner-occupied commercial real estate [Member]
Loans and Leases	212,301,539		204,911,308
Commercial construction, land development, and other land [Member]
Loans and Leases	46,449,160		44,962,381
Other commercial real estate [Member]
Loans and Leases	339,882,919		344,105,550
Total Commercial [Member]
Loans and Leases	598,633,618		593,979,239
Leases receivable [Member]
Loans and Leases	109,654,314		103,685,656
Plus deferred loan/lease origination costs	4,198,286		3,907,140
Total Loans/Leases plus deferred loan/lease origination costs	113,852,600		107,592,796
Less allowance for estimated losses on loans/leases	(2,296,523)		(1,990,395)		(1,366,528)	(1,339,496)
Loans/leases net of allowance for estimated losses	111,556,077		105,602,401
* Direct financing leases:
Net minimum lease payments to be received	124,469,580		117,719,380
Estimated unguaranteed residual values of leased assets	1,060,990		1,095,848
Unearned lease/residual income	(15,876,256)		(15,129,572)
Mortgage Receivable [Member]
Loans and Leases	115,548,209	[1]	115,581,573	[1]
Loans Receivable [Member]
Loans and Leases	66,293,903		76,720,514
Total [Member]
Loans and Leases	1,288,252,284		1,284,211,234
Plus deferred loan/lease origination costs	3,543,227		3,176,405
Total Loans/Leases plus deferred loan/lease origination costs	1,291,795,511		1,287,387,639
Less allowance for estimated losses on loans/leases	$ (20,769,462)		$ (19,925,204)

[1] Includes residential real estate loans held for sale totaling $2,260,506 and $4,577,233 as of March 31, 2013, and December 31, 2012, respectively.