Note 7 - Loans and Allowance for Credit Losses on Loans - Amortized Cost of Modified Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Extended Maturity [Member]
Amortized cost, modified, subsequently defaulted	$ 438
Extended Maturity and Payment Deferral [Member]
Amortized cost, modified, subsequently defaulted	66
Commercial Loan [Member] | Extended Maturity [Member]
Amortized cost, modified, subsequently defaulted	278
Commercial Loan [Member] | Extended Maturity and Payment Deferral [Member]
Amortized cost, modified, subsequently defaulted	0
Residential 1-4 Family Real Estate, Personal Residence [Member]
Amortized cost, modified, subsequently defaulted		$ 22	$ 44
Residential 1-4 Family Real Estate, Personal Residence [Member] | Extended Maturity [Member]
Amortized cost, modified, subsequently defaulted	0
Residential 1-4 Family Real Estate, Personal Residence [Member] | Extended Maturity and Payment Deferral [Member]
Amortized cost, modified, subsequently defaulted	66
Residential 1-4 Family Real Estate, Rental Small Loan [Member] | Extended Maturity [Member]
Amortized cost, modified, subsequently defaulted	160
Residential 1-4 Family Real Estate, Rental Small Loan [Member] | Extended Maturity and Payment Deferral [Member]
Amortized cost, modified, subsequently defaulted	$ 0