Note 2 - Investments - Gross Unrealized Losses (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Available-for-sale securities, less than 12 months, fair value	$ 31,658,456	$ 24,036,504
Available-for-sale securities, less than 12 months, unrealized loss	(443,400)	(328,909)
US Treasury securities	28,927,073	31,461,798
US Treasury securities	(4,325,330)	(4,047,205)
Available-for-sale securities, fair value	60,585,529	55,498,302
Debt Securities, Gross Unrealized Loss	(4,768,730)	(4,376,114)
US Treasury Securities [Member]
Available-for-sale securities, less than 12 months, fair value	449,896	0
Available-for-sale securities, less than 12 months, unrealized loss	(1,082)	0
US Treasury securities	276,901	280,278
US Treasury securities	(81,915)	(78,925)
Available-for-sale securities, fair value	726,797	280,278
Debt Securities, Gross Unrealized Loss	(82,997)	(78,925)
Corporate Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value	12,992,131	8,857,877
Available-for-sale securities, less than 12 months, unrealized loss	(179,871)	(122,197)
US Treasury securities	11,702,480	12,403,317
US Treasury securities	(2,739,522)	(2,500,118)
Available-for-sale securities, fair value	24,694,611	21,261,194
Debt Securities, Gross Unrealized Loss	(2,919,393)	(2,622,315)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value	1,591,559	1,163,445
Available-for-sale securities, less than 12 months, unrealized loss	(41,535)	(27,032)
US Treasury securities	4,062,792	4,293,247
US Treasury securities	(532,630)	(509,376)
Available-for-sale securities, fair value	5,654,351	5,456,692
Debt Securities, Gross Unrealized Loss	(574,165)	(536,408)
Redeemable Preferred Stock [Member]
Available-for-sale securities, less than 12 months, fair value	74,156	0
Available-for-sale securities, less than 12 months, unrealized loss	(389)	0
US Treasury securities	1,343,770	1,521,302
US Treasury securities	(177,054)	(147,491)
Available-for-sale securities, fair value	1,417,926	1,521,302
Debt Securities, Gross Unrealized Loss	(177,443)	(147,491)
Term Loans [Member]
Available-for-sale securities, less than 12 months, fair value	0	897,477
Available-for-sale securities, less than 12 months, unrealized loss	0	(1,338)
US Treasury securities	5,735,961	6,843,379
US Treasury securities	(181,390)	(190,174)
Available-for-sale securities, fair value	5,735,961	7,740,856
Debt Securities, Gross Unrealized Loss	(181,390)	(191,512)
Collateralized Mortgage-Backed Securities [Member]
Available-for-sale securities, less than 12 months, fair value	16,550,714	13,117,705
Available-for-sale securities, less than 12 months, unrealized loss	(220,523)	(178,342)
US Treasury securities	5,805,169	6,120,275
US Treasury securities	(612,819)	(621,121)
Available-for-sale securities, fair value	22,355,883	19,237,980
Debt Securities, Gross Unrealized Loss	$ (833,342)	$ (799,463)