Note 1 - Summary of Significant Accounting Policies - Accumulated Other Comprehensive Earnings (Details) - USD ($)	3 Months Ended					9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Balance	$ 67,613,677	$ 68,685,411	$ 67,003,549	$ 63,598,529	$ 60,440,931	$ 67,003,549	$ 60,440,931
Net current period other comprehensive earnings (loss)	3,234,962	(480,032)	(640,112)	(764,329)	1,596,353
Balance	73,103,488	67,613,677	68,685,411	63,354,040	63,598,529	73,103,488	59,586,450
AOCI Attributable to Parent [Member]
Balance	(7,741,480)	(7,261,448)	(6,621,336)	(7,245,164)	(8,841,517)	(6,621,336)	(8,841,517)
Other comprehensive earnings (loss) before reclassification						2,097,770	(2,239,651)
Amount reclassified from accumulated other comprehensive earnings						17,048	46,421
Net current period other comprehensive earnings (loss)	3,234,962	(480,032)	(640,112)	(764,329)	1,596,353	2,114,818	(2,193,230)
Balance	$ (4,506,518)	$ (7,741,480)	$ (7,261,448)	$ (8,009,493)	$ (7,245,164)	$ (4,506,518)	$ (11,034,747)