Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		9 Months Ended		12 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Average recorded investment in impaired loans(1)	[1]	$ 3,067	$ 6,108	$ 5,901
Interest income recognized on impaired loans, after designation as impaired		13	175	137
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1]	189	193	192
Interest income recognized on impaired loans, after designation as impaired		9	9	13
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1]	2,601	2,866	2,668
Interest income recognized on impaired loans, after designation as impaired		4	72	9
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1]		2,724	2,723
Interest income recognized on impaired loans, after designation as impaired			83	100
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment in impaired loans(1)	[1]	277	324	317
Interest income recognized on impaired loans, after designation as impaired		$ 0	11	15
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1]		1	1
Interest income recognized on impaired loans, after designation as impaired			$ 0	$ 0

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