Note 7 - Derivatives and Hedging Activities - Changes in Fair Values of Derivative Financial Instruments (Details) - Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Unrealized loss at beginning of period, net of tax	$ (805,027)	$ (932,156)
Amount of loss recognized in other comprehensive income, net of tax	(1,073,815)	(357,762)
Unrealized loss at end of period, net of tax	(1,276,188)	(805,027)
Hedge Ineffectiveness [Member] | Noninterest Expense [Member]
Amount reclassified from accumulated other comprehensive income	27,407	79,757
Caplet Amortization [Member]
Amount reclassified from accumulated other comprehensive income	$ 575,247	$ 405,134