Note 10 - Income Per Common Share - Income Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Available to Common Stockholders, basic	$ 2,120,364	$ 1,355,745
Weighted Average Common Shares Outstanding, basic (in shares)	4,438,625	4,391,717
Basic Income Per Common Share (in dollars per share)	$ 0.48	$ 0.31
Effect of Dilutive Securities, Average Common Shares Outstanding (in shares)	60,337	75,069
Income Available to Common Stockholders, diluted	$ 2,120,364	$ 1,355,745
Weighted Average Common Shares Outstanding, diluted (in shares)	4,498,962	4,466,786
Diluted Income Per Common Share (in dollars per share)	$ 0.47	$ 0.30