Note 1 - Summary of Significant Accounting Policies - Weighted Average Common Shares Outstanding (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Net income	$ 20,327,380	$ 7,293,066
Weighted average common shares (in shares)	13,720,699	13,643,355
Dilutive potential common shares (in shares)	63,594	0
Weighted average dilutive common shares outstanding (in shares)	13,784,293	13,643,355
Earnings per share:
Basic (in dollars per share)	$ 1.48	$ 0.53
Diluted (in dollars per share)	$ 1.47	$ 0.53