Note 10 - Income Per Common Share - Income Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic Income Per Common Share	$ 1,883,383	$ 2,428,499	$ 3,988,228	$ 4,548,863
Basic Income Per Common Share (in shares)	4,337,274	4,452,798	4,323,358	4,445,750
Basic Income Per Common Share (in dollars per share)	$ 0.43	$ 0.55	$ 0.92	$ 1.02
Effect of Dilutive Securities, Average Common Shares Outstanding (in shares)	3,477	51,166	20,552	55,631
Diluted Income Per Common Share	$ 1,883,383	$ 2,428,499	$ 3,988,228	$ 4,548,863
Diluted Income Per Common Share (in shares)	4,340,751	4,503,964	4,343,910	4,501,381
Diluted Income Per Common Share (in dollars per share)	$ 0.43	$ 0.54	$ 0.92	$ 1.01