Note 4 - Loans and the Allowance for Credit Losses - Reversal of Accrued Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Interest income reversed	$ 9	$ 71	$ 396	$ 450
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Interest income reversed	0	17	49	28
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Interest income reversed	0	41	156	381
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Interest income reversed	0	2	162	7
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Interest income reversed	4	0	4	0
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Interest income reversed	0	1	0	1
Residential Portfolio Segment [Member] \| Equity Lines of Credit [Member]
Interest income reversed	2	3	15	18
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Interest income reversed	2	7	8	14
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Interest income reversed	$ 1	$ 0	$ 2	$ 1