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	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	$ 10,659	$ 14,550
Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans, fair value	7,330	17,264
Residential Portfolio Segment [Member]
Collateral dependent loans, fair value		1,392
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member]
Collateral dependent loans, fair value	10,659	14,550
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Valuation, Market Approach [Member]
Collateral dependent loans, fair value	$ 10,205	$ 14,028
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Valuation, Market Approach [Member] | Maximum [Member]
Collateral dependent loans, rate	92	96
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Valuation, Market Approach [Member] | Weighted Average [Member]
Collateral dependent loans, rate	68	67
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Average Transfer Price as Price to Unpaid Principal Balance [Member] | Valuation, Market Approach [Member] | Minimum [Member]
Collateral dependent loans, rate	65	65
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member]
Collateral dependent loans, fair value	$ 454	$ 522
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Maximum [Member]
Collateral dependent loans, rate	25	13
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Weighted Average [Member]
Collateral dependent loans, rate	0.1	3
Fair Value, Inputs, Level 3 [Member] | Commercial Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Minimum [Member]
Collateral dependent loans, rate	(7.5)	(10)
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans, fair value	$ 7,330	$ 17,264
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member]
Collateral dependent loans, fair value	$ 7,330	$ 17,264
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Maximum [Member]
Collateral dependent loans, rate	5	0
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Weighted Average [Member]
Collateral dependent loans, rate	4	15
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Minimum [Member]
Collateral dependent loans, rate	(15)	(20)
Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member]
Collateral dependent loans, fair value		$ 1,392
Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member]
Collateral dependent loans, fair value		$ 1,392
Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Maximum [Member]
Collateral dependent loans, rate		39
Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Weighted Average [Member]
Collateral dependent loans, rate		22
Fair Value, Inputs, Level 3 [Member] | Residential Portfolio Segment [Member] | Measurement Input, Comparability Adjustment [Member] | Appraisals of Collateral Value [Member] | Minimum [Member]
Collateral dependent loans, rate		21