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, 2021	Dec. 31, 2020
Average recorded investment in impaired loans(1)	[1]	$ 5,901	$ 5,093
Interest income recognized		137	54
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1],[2]	192	196
Interest income recognized	[2]	13	13
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1],[2]	2,668	3,217
Interest income recognized	[2]	9	19
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1],[2]	2,723	790
Interest income recognized	[2]	100	0
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment in impaired loans(1)	[1],[2]	317	887
Interest income recognized	[2]	15	22
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[1],[2]	$ 1	$ 3

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

[2] Only classes with impaired loans are shown.