Note 3 - Investments, Held to Maturity (Details Textual)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	$ 163,072,000	$ 167,438,000
Debt Securities, Held-to-Maturity, Fair Value	$ 158,540,000	$ 161,464,000
Debt Securities, Held-to-Maturity, Weighted Average Yield	4.85%
Debt Securities, Held to Maturity, Unrealized Loss Position, Number of Positions	55	54
Debt Securities, Held to Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	42	6
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	$ 163,072,000	$ 167,438,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, 90 Days or More Past Due, Still Accruing	0
Debt Securities, Held-to-Maturity, Nonaccrual	0
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss	788,000
Commitments on Mortgage Loans [Member]
Debt Securities, Held-to-Maturity, Fair Value	14,300,000	16,200,000
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	14,600,000	16,700,000
Asset Pledged as Collateral [Member] | Deposit Accounts, FHLB Advances and Other Borrowings [Member]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	107,500,000	25,300,000
Debt Securities, Held-to-Maturity, Fair Value	$ 103,800,000	$ 24,500,000