Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Average recorded investment	[1],[2]	$ 3,776	$ 5,901
Interest income recognized	[1]	18	137
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment	[1],[2]	188	192
Interest income recognized	[1]	13	13
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment	[1],[2]	2,587	2,668
Interest income recognized	[1]	5	9
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment		729	2,723	[1],[2]
Interest income recognized		0	100	[1]
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment	[1],[2]	272	317
Interest income recognized	[1]	$ 0	15
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Average recorded investment	[1],[2]		1
Interest income recognized	[1]		$ 0

[1] Only classes with impaired loans are shown.

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