Note 8 - Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 1,096,287	$ 1,122,118
Weighted average shares outstanding (in shares)	1,682,997	1,667,833
Earnings per share - basic and diluted (in dollars per share)	$ 0.65	$ 0.67