Note 3 - Loans Leases Receivable (Details Textual)		3 Months Ended
		Mar. 31, 2018 USD ($)		Dec. 31, 2017 USD ($)		Mar. 31, 2017 USD ($)
Loans and Leases Receivable, Net of Deferred Income, Total		$ 3,046,799,276		$ 2,956,713,493
Loans and Leases Receivable, Loss		0				$ 0
Financing Receivable, Recorded Investment, Nonaccrual Status		12,758,985		11,441,234
Financing Receivable, Modifications, Recorded Investment		$ 7,912,975		9,394,967
Financing Receivable, Modifications, Number of Contracts		3				11
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 93,844				$ 809,813
Financing Receivable, Modifications, Subsequent Default, Number of Contracts		8				2
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down				195,000
One Customer [Member]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 78,000
Other Customers [Member]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 378,000
Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		1
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 46,320				$ 0
Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		2,637,483		2,282,495
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[1]	1,201,085,625		1,134,516,315
Financing Receivable, Recorded Investment, Nonaccrual Status		1,448,542		1,231,353	[2]
Commercial Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		25,984		122,598
Commercial Portfolio Segment [Member] | m2 Lease Funds, LLC [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		78,911,791		66,758,397
Residential Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[3]	254,484,231	[4]	258,646,265
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage		279,750		645,001
Financing Receivable, Recorded Investment, Nonaccrual Status		1,187,267		1,363,806	[2]
Residential Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		84,555		115,190
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		1,357,703,386		1,303,491,882
Commercial Real Estate Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		1,312,469		1,336,871
Finance Leases Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[1],[4]	137,614,465		141,448,232
Financing Receivable, Recorded Investment, Nonaccrual Status		2,806,398		2,175,044	[2]
Finance Leases Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		1,208,050		700,255
Consumer Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[4]	95,911,569		118,610,799
Financing Receivable, Recorded Investment, Nonaccrual Status		267,187		249,091	[2]
Consumer Portfolio Segment [Member] | Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 6,425		$ 7,581

[1] Includes equipment financing agreements outstanding at m2, totaling $78,911,791 and $66,758,397 as of March 31, 2018 and December 31, 2017, respectively.

[2] Nonaccrual loans/leases included $2,282,495 of TDRs, including $122,598 in C&I loans, $1,336,871 in CRE loans, $700,255 in direct financing leases, $115,190 in residential real estate loans, and $7,581 in installment loans.

[3] Includes residential real estate loans held for sale totaling $279,750 and $645,001 as of March 31, 2018, and December 31, 2017, respectively.

[4] Performing = loans/leases accruing and less than 90 days past due. Nonperforming = loans/leases on nonaccrual, accruing loans/leases that are greater than or equal to 90 days past due, and accruing TDRs.