Note 9 - Income Per Common Share - Income Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic Income Per Common Share	$ (342,984)	$ 1,592,573	$ 1,012,761	$ 3,021,814
Basic Income Per Common Share (in shares)	4,404,029	4,374,725	4,397,907	4,368,921
Basic Income (Loss) Per Common Share (in dollars per share)	$ (0.08)	$ 0.36	$ 0.23	$ 0.69
Effect of Dilutive Securities (in shares)		51,686	71,513	54,439
Diluted Income Per Common Share	$ (342,984)	$ 1,592,573	$ 1,012,761	$ 3,021,814
Diluted Income Per Common Share (in shares)	4,404,029	4,426,411	4,469,420	4,423,360
Diluted Income (Loss) Per Common Share (in dollars per share)	$ (0.08)	$ 0.36	$ 0.23	$ 0.68