Note 1 - Summary of Significant Accounting Policies - Other Comprehensive Earnings (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Unrealized holding gains (losses) arising during the period, pre tax	$ 1,980,180	$ (6,280,234)
Unrealized holding gains (losses) arising during the period, tax	(415,838)	1,318,849
Unrealized holding gains (losses) arising during the period, after tax	1,564,342	(4,961,385)
Reclassification adjustment for losses (gains) included in net earnings, pre-tax	40,520	(9,727)
Reclassification adjustment for losses (gains) included in net earnings, tax	(8,509)	2,043
Reclassification adjustment for losses (gains) included in net earnings, after-tax	32,011	(7,684)
Total other comprehensive earnings (loss), pre-tax	2,020,700	(6,289,961)
Total other comprehensive earnings (loss), tax	(424,347)	1,320,892
Total other comprehensive earnings (loss)	$ 1,596,353	$ (4,969,069)