Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans and Associated Reserves (Details) - USD ($) $ in Thousands		Sep. 30, 2021		Dec. 31, 2020		Sep. 30, 2020
Principal balance		$ 6,709		$ 5,453
Total recorded investment		6,084	[1]	4,903	[1]	$ 4,995
Recorded investment for which there is a related allowance		0	[1]	1,045	[1]	1,056
Related allowance		(0)		75		104
Recorded investment for which there is no related allowance		6,084	[1]	3,858	[1]	$ 3,939
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Principal balance	[2]	192		194
Total recorded investment	[1],[2]	192		194
Recorded investment for which there is a related allowance	[1],[2]	0		194
Related allowance	[2]	0		2
Recorded investment for which there is no related allowance	[1],[2]			0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Principal balance	[2]	3,481		3,752
Total recorded investment	[1],[2]	2,861		3,202
Recorded investment for which there is no related allowance	[1],[2]	2,861		3,202
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Principal balance	[2]	2,722		654
Total recorded investment	[1],[2]	2,722		654
Recorded investment for which there is no related allowance	[1],[2]	2,722		654
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Principal balance	[2]	313		851
Total recorded investment	[1],[2]	308		851
Recorded investment for which there is a related allowance	[1],[2]	0		851
Related allowance	[2]	0		73
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Principal balance	[2]	1		2
Total recorded investment	[1],[2]	1		2
Recorded investment for which there is no related allowance	[1],[2]	$ 1		$ 2

[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.