Note 6 - Fair Value Measurements and Fair Value of Financial Instruments - Assets Measured on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Commercial Portfolio Segment [Member]
Collateral dependent loans	$ 10,659	$ 14,550
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Collateral dependent loans	0	0
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Collateral dependent loans	0	0
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans	10,659	14,550
Commercial Real Estate Portfolio Segment [Member]
Collateral dependent loans	7,330	17,264
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Collateral dependent loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Collateral dependent loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans	$ 7,330	17,264
Residential Portfolio Segment [Member]
Collateral dependent loans		1,392
Residential Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Collateral dependent loans		0
Residential Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Collateral dependent loans		0
Residential Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans		$ 1,392