Note 5 - Allowance for Loan Losses on Loans and Nonperforming Assets - Impaired Loans, Average Investment and Interest Income (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Average recorded investment	$ 3,776	[1]
Interest income recognized	18
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment	188	[1]
Interest income recognized	13
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment	2,587	[1]
Interest income recognized	5
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment	729
Interest income recognized	0
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment	272	[1]
Interest income recognized	$ 0

[1] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.