Note 3 - Securities Held to Maturity - Summary of Amortized Cost, Fair Value, and Gross Unrecognized Gains and Losses of Securities Held to Maturity (Details) - USD ($)	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Securities held to maturity, amortized cost	$ 80,211,754		$ 72,656,179
Held to maturity, gross unrealized gains	142,989		46,691
Held to maturity, gross unrealized losses	(5,751,645)		(7,328,117)
Securities held to maturity, fair value	74,603,097		65,374,753
Allowance for credit losses	(108,000)	$ (108,000)	0	$ 0	$ 0	$ 0
Securities held to maturity, net of allowance for securities credit losses of $108,000 and zero, respectively (fair value - $74,603,097 and $65,374,753, respectively)	80,103,753		72,656,179
Total	74,495,097
US Government Agencies Debt Securities [Member]
Held to maturity, amortized cost, less than one year	10,000,000
Held to maturity, gross unrealized gains, less than one year	0
Held to maturity, gross unrealized losses, less than one year	(116,890)
Held to maturity, fair value, less than one year	9,883,110
Held to maturity, amortized cost, five through ten years	3,000,000		3,000,000
Held to maturity, gross unrealized gains, five through ten years	0		0
Held to maturity, gross unrealized losses, five through ten years	(250,632)		(372,885)
Held to maturity, fair value, five through ten years	2,749,368		2,627,115
Held to maturity, amortized cost, one through five years			10,000,000
Held to maturity, gross unrealized gains, one through five years			0
Held to maturity, gross unrealized losses, one through five years			(314,240)
Held to maturity, fair value, one through five years			9,685,760
Securities held to maturity, amortized cost	13,000,000		13,000,000
Allowance for credit losses	0	0	0	0	0	0
Corporate Debt Securities [Member]
Held to maturity, amortized cost, five through ten years	20,408,373		16,294,604
Held to maturity, gross unrealized gains, five through ten years	56,747		38,684
Held to maturity, gross unrealized losses, five through ten years	(1,816,554)		(2,074,007)
Held to maturity, fair value, five through ten years	18,648,566		14,259,281
Held to maturity, amortized cost, one through five years	8,099,945		6,431,007
Held to maturity, gross unrealized gains, one through five years	59,158		0
Held to maturity, gross unrealized losses, one through five years	(84,703)		(52,685)
Held to maturity, fair value, one through five years	8,074,400		6,378,322
Held to maturity, amortized cost, greater than ten years	4,313,175		4,287,941
Held to maturity, gross unrealized gains, greater than ten years	0		0
Held to maturity, gross unrealized losses, greater than ten years	(6,025)		(441)
Held to maturity, fair value, greater than ten years	4,307,150		4,287,500
Securities held to maturity, amortized cost	32,821,494		27,013,552
Allowance for credit losses	(108,000)	(108,000)	0	0	0	0
US States and Political Subdivisions Debt Securities [Member]
Held to maturity, amortized cost, five through ten years	1,588,709		1,591,199
Held to maturity, gross unrealized gains, five through ten years	158		784
Held to maturity, gross unrealized losses, five through ten years	(184,589)		(160,655)
Held to maturity, fair value, five through ten years	1,404,278		1,431,328
Held to maturity, amortized cost, one through five years	900,882		901,597
Held to maturity, gross unrealized gains, one through five years	0		0
Held to maturity, gross unrealized losses, one through five years	(25,695)		(55,102)
Held to maturity, fair value, one through five years	875,187		846,495
Held to maturity, amortized cost, greater than ten years	506,960		507,716
Held to maturity, gross unrealized gains, greater than ten years	0		0
Held to maturity, gross unrealized losses, greater than ten years	(83,495)		(103,356)
Held to maturity, fair value, greater than ten years	423,465		404,360
Securities held to maturity, amortized cost	2,996,551		3,000,512
Allowance for credit losses	0	0	0	0	0	0
Residential Mortgage-Backed Securities [Member]
Securities held to maturity, amortized cost	14,676,749		12,484,366
Held to maturity, gross unrealized gains	26,926		7,223
Held to maturity, gross unrealized losses	(1,108,642)		(1,457,104)
Securities held to maturity, fair value	13,595,033		11,034,485
Allowance for credit losses	0	0	0	0	0	0
Commercial Mortgage-Backed Securities [Member]
Securities held to maturity, amortized cost	16,716,960		17,157,749
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	(2,074,420)		(2,737,642)
Securities held to maturity, fair value	14,642,540		14,420,107
Allowance for credit losses	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0