Note 4 - Fair Value Measurements - Assets Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Loans held for sale, Total gains (losses)	$ 10	$ (26)
Mortgage servicing rights, Total gains (losses)	0	0
Collateral dependent loans, Total gains (losses)	8	(287)
Total, Total gains (losses)	18	(313)
Fair Value, Nonrecurring [Member]
Loans held for sale	4,146	1,006
Mortgage servicing rights, net	2,631	2,709
Collateral dependent loans	2,841	3,856
Total	9,618	7,571
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Loans held for sale	0	0
Mortgage servicing rights, net	0	0
Collateral dependent loans	0	0
Total	0	0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Loans held for sale	4,146	1,006
Mortgage servicing rights, net	0	0
Collateral dependent loans	2,841	3,856
Total	6,987	4,862
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Loans held for sale	0	0
Mortgage servicing rights, net	2,631	2,709
Collateral dependent loans	0	0
Total	$ 2,631	$ 0