Note 4 - Loans and the Allowance for Credit Losses (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Deferred Loan Origination Costs	$ 700,000	$ 562,000
Financing Receivable, Nonaccrual	5,610,000		$ 4,820,000
Financing Receivable, Allowance for Credit Loss, Nonaccrual Loans	28,000		28,000
Nonaccrual, Specific Reserves [Member]
Financing Receivable, Nonaccrual	57,000		57,000
Nonaccrual, Interest Income, Cash Basis Method [Member]
Financing Receivable, Nonaccrual, Interest Income	0		$ 0
Agricultural Loans [Member]
Financing Receivable, Modified, Subsequent Default	$ 2,900,000