Note 8 - Derivative Financial Instruments (Details Textual) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		$ (76,222)		$ 151,420
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	95,395
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ 56,025