Note 9 - Financial and Off-balance Sheet Instruments (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 76,909,000	$ 62,657,000
Available-for-sale	460,418,000	490,182,000
Equity securities	7,233,000	5,910,000
Restricted investment in stocks	3,114,000	2,730,000
Loans held for sale	786,000	549,000
Net loans	1,153,452,000	1,084,681,000
Mortgage servicing rights	399,000	415,000
Accrued interest receivable	6,402,000	6,101,000
Deposits	1,572,839,000	1,488,713,000
Short-term borrowings	49,066,000	94,094,000
Long-term debt	30,000,000	20,000,000
Accrued interest payable	4,488,000	5,294,000
Cash and cash equivalents	76,909,000	62,657,000
Restricted investment in stocks	3,114,000	2,730,000
Loans held for sale	790,000	560,000
Net loans	1,144,269,000	1,077,544,000
Mortgage servicing rights	580,000	585,000
Accrued interest receivable	6,402,000	6,101,000
Short-term borrowings	49,066,000	94,094,000
Long-term debt	29,903,000	19,906,000
Accrued interest payable	4,488,000	5,294,000
Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Equity securities	7,233,000	5,910,000
Cash and cash equivalents	76,909,000	62,657,000
Short-term borrowings	49,066,000	94,094,000
Long-term debt	29,903,000	19,906,000
Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Available-for-sale	460,366,000	490,130,000
Restricted investment in stocks	3,114,000	2,730,000
Accrued interest receivable	6,402,000	6,101,000
Accrued interest payable	4,488,000	5,294,000
Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Available-for-sale	52,000	52,000
Net loans	1,144,269,000	1,077,544,000
Mortgage servicing rights	580,000	585,000
Standby Letters of Credit [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Commitments to extend credit	46,000	79,000
Standby Letters of Credit [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Commitments to extend credit	46,000	79,000
With No Stated Maturities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deposits	1,194,146,000	1,173,732,000
Deposits	1,194,146,000	1,173,732,000
With No Stated Maturities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deposits	1,194,146,000	1,173,732,000
With Stated Maturities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deposits	378,693,000	314,981,000
Deposits	375,939,000	311,735,000
With Stated Maturities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deposits	$ 375,939,000	$ 311,735,000