Note 1 - Summary of Significant Accounting Policies - Other Comprehensive Earnings (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Unrealized holding gains (losses) arising during the period, pre tax	$ 4,094,889	$ (3,836,298)	$ 2,655,405	$ (2,835,001)
Unrealized holding gains (losses) arising during the period, tax	(859,927)	805,622	(557,635)	595,350
Unrealized holding gains (losses) arising during the period, after tax	3,234,962	(3,030,676)	2,097,770	(2,239,651)
Reclassification adjustment for losses included in net earnings, pre tax	0	6,863	21,580	58,761
Reclassification adjustment for losses included in net earnings, tax	0	(1,441)	(4,532)	(12,340)
Reclassification adjustment for losses included in net earnings, after tax	0	5,422	17,048	46,421
Total other comprehensive earnings (loss), pre tax	4,094,889	(3,829,435)	2,676,985	(2,776,240)
Total other comprehensive earnings (loss), tax	(859,927)	804,181	(562,167)	583,010
Total other comprehensive earnings (loss), after tax	$ 3,234,962	$ (3,025,254)	$ 2,114,818	$ (2,193,230)