Note 11 - Derivative Financial Instruments (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	$ 502,917	$ 227,642	$ 1,768,729	$ 227,642
Interest Rate Swap [Member]
Derivative, Notional Amount	$ 50,000,000	$ 50,000,000	50,000,000	$ 50,000,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			1,740,642
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax			$ 508,158