Note 6 - Derivatives and Hedging Activities (Details) - Changes in Fair Values of Derivative Financial Instruments - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amount of loss recognized in other comprehensive income, net of tax	$ (188,613)	$ 11,708,770	$ (18,350,669)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized loss at beginning of period, net of tax	(399,367)
Amount of loss recognized in other comprehensive income, net of tax	(415,949)	(369,220)
Unrealized loss at end of period, net of tax	(799,421)	(399,367)
Hedge Ineffectiveness [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
	(156)	(30,212)
Caplet Amortization [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
	$ 16,051	$ 65