Note 10 - Income Per Common Share - Income Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basic Income per Common Share	$ 2,104,845	$ 2,120,364
Basic Income per Common Share (in shares)	4,309,441	4,438,625
Basic Income per Common Share (in dollars per share)	$ 0.49	$ 0.48
Effect of Dilutive Securities, Average Common Shares Outstanding (in shares)	26,861	60,337
Diluted Income per Common Share	$ 2,104,845	$ 2,120,364
Diluted Income per Common Share (in shares)	4,336,302	4,498,962
Diluted Income per Common Share (in dollars per share)	$ 0.49	$ 0.47