Note 6 - Fair Value Measurements and Fair Value of Financial Instruments - Significant Unobservable Inputs for Assets Measured on Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] $ in Thousands	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	$ 763	$ 657
Collateral dependent loans, fair value	763	657
Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans, fair value		7,005
Collateral dependent loans, fair value		7,005
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	763	657
Collateral dependent loans, fair value	$ 763	657
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Valuation, Market Approach [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member]
Collateral dependent loans, fair value		657
Collateral dependent loans, fair value		$ 657
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Valuation, Market Approach [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Minimum [Member]
Collateral dependent loans, rate		0.001
Collateral dependent loans, rate		0.001
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Valuation, Market Approach [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Maximum [Member]
Collateral dependent loans, rate		(0.075)
Collateral dependent loans, rate		(0.075)
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Valuation, Market Approach [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Weighted Average [Member]
Collateral dependent loans, rate		0.25
Collateral dependent loans, rate		0.25
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Minimum [Member]
Collateral dependent loans, rate	(0.075)
Collateral dependent loans, rate	(0.075)
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Maximum [Member]
Collateral dependent loans, rate	0.25
Collateral dependent loans, rate	0.25
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Weighted Average [Member]
Collateral dependent loans, rate	0.008
Collateral dependent loans, rate	0.008
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans, fair value		$ 7,005
Collateral dependent loans, fair value		7,005
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member]
Collateral dependent loans, fair value		7,005
Collateral dependent loans, fair value		$ 7,005
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Minimum [Member]
Collateral dependent loans, rate		0.103
Collateral dependent loans, rate		0.103
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Maximum [Member]
Collateral dependent loans, rate		(0.15)
Collateral dependent loans, rate		(0.15)
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Appraisals of Collateral Value [Member] | Measurement Input, Comparability Adjustment [Member] | Weighted Average [Member]
Collateral dependent loans, rate		0
Collateral dependent loans, rate		0