Note 9 - Fair Value Measurements - Quantitative Information About Level 3 Fair Value Measurements for Financial Instruments Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2026 USD ($)	Dec. 31, 2025 USD ($)
Collateral dependent loans, fair value	$ 3,681	$ 1,988
Other Real Estate Owned and Receivables, Fair Value		226
Commercial Loans [Member]
Collateral dependent loans, fair value	0	84
Agricultural Loans [Member]
Collateral dependent loans, fair value	1,722	1,904
Real Estate Loan [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	1,959
Real Estate Loan [Member] \| Residential Portfolio Segment [Member]
RE – Residential, fair value		91
Equity Lines of Credit [Member] \| Residential Portfolio Segment [Member]
Equity lines of credit, fair value	135	135
Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans, fair value	3,681	1,988
Other Real Estate Owned and Receivables, Fair Value		226
Fair Value, Inputs, Level 3 [Member] \| Commercial Loans [Member]
Collateral dependent loans, fair value	0	84
Fair Value, Inputs, Level 3 [Member] \| Agricultural Loans [Member]
Collateral dependent loans, fair value	1,722	1,904
Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member]
RE – Residential, fair value		91
Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	1,959
Fair Value, Inputs, Level 3 [Member] \| Equity Lines of Credit [Member] \| Residential Portfolio Segment [Member]
Equity lines of credit, fair value	135	135
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans, fair value	3,681	1,988
Other Real Estate Owned and Receivables, Fair Value	135	226
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commercial Loans [Member]
Collateral dependent loans, fair value	$ 0	$ 84
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commercial Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Minimum [Member]
Collateral dependent loans, measurement input	1	0.14
Collateral dependent loans, measurement input	1	0.14
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commercial Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Maximum [Member]
Collateral dependent loans, measurement input	1	1
Collateral dependent loans, measurement input	1	1
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Commercial Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Weighted Average [Member]
Collateral dependent loans, measurement input	1	0.45
Collateral dependent loans, measurement input	1	0.45
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Agricultural Loans [Member]
Collateral dependent loans, fair value	$ 1,722	$ 1,904
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Agricultural Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Minimum [Member]
Collateral dependent loans, measurement input	0.07	0.02
Collateral dependent loans, measurement input	0.07	0.02
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Agricultural Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Maximum [Member]
Collateral dependent loans, measurement input	1	1
Collateral dependent loans, measurement input	1	1
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Agricultural Loans [Member] \| Measurement Input, Manager Adjustments [Member] \| Weighted Average [Member]
Collateral dependent loans, measurement input	0.59	0.43
Collateral dependent loans, measurement input	0.59	0.43
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member]
RE – Residential, fair value	$ 0	$ 91
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	$ 1,959	$ 0
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Measurement Input, Manager Adjustments [Member] \| Minimum [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, measurement input	0.04
Collateral dependent loans, measurement input	0.04
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Measurement Input, Manager Adjustments [Member] \| Maximum [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, measurement input	0.13
Collateral dependent loans, measurement input	0.13
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Measurement Input, Manager Adjustments [Member] \| Weighted Average [Member]
Other Real Estate, measurement input	0	0.60
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Real Estate Loan [Member] \| Measurement Input, Manager Adjustments [Member] \| Weighted Average [Member] \| Commercial Portfolio Segment [Member]
Collateral dependent loans, measurement input	0.05
Collateral dependent loans, measurement input	0.05
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Equity Lines of Credit [Member] \| Residential Portfolio Segment [Member]
Equity lines of credit, fair value	$ 135	$ 135
Third Party Appraisals [Member] \| Fair Value, Inputs, Level 3 [Member] \| Equity Lines of Credit [Member] \| Measurement Input, Manager Adjustments [Member] \| Weighted Average [Member] \| Residential Portfolio Segment [Member]
Equity lines of credit, measurement input	0.10	0.10

Note 9 - Fair Value Measurements - Quantitative Information About Level 3 Fair Value Measurements for Financial Instruments Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member]
$ in Thousands