Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans and Associated Reserves (Details) - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019		Sep. 30, 2019
Principal balance		$ 5,522		$ 5,757
Total recorded investment		4,995	[1]	5,289	[1]	$ 6,233
Recorded investment for which there is no related allowance		3,939	[1]	4,174	[1]	5,163
Recorded investment for which there is a related allowance		1,056	[1]	1,115	[1]	1,070
Related allowance		104		110		$ 120
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Principal balance	[1]	244		441
Total recorded investment	[1]	244	[2]	438
Recorded investment for which there is no related allowance	[1]	49	[2]	241
Recorded investment for which there is a related allowance	[1]	195	[2]	197
Related allowance	[1]	2		2
Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Principal balance				100
Total recorded investment				100
Recorded investment for which there is no related allowance				100
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Principal balance	[1]			221
Total recorded investment	[1]			221
Recorded investment for which there is no related allowance	[1]			221
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Principal balance	[1]	893		929
Total recorded investment	[1]	846	[2]	895
Recorded investment for which there is no related allowance	[1]	846	[2]	895
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Principal balance	[1]	3,521		2,867
Total recorded investment	[1]	3,041	[2]	2,435
Recorded investment for which there is no related allowance	[1]	3,041	[2]	2,435
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Principal balance	[1]			278
Total recorded investment	[1]			278
Recorded investment for which there is no related allowance	[1]			278
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Principal balance	[1]	861		917
Total recorded investment	[1]	861	[2]	918
Recorded investment for which there is a related allowance	[1]	861	[2]	918
Related allowance	[1]	102		108
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Principal balance	[1]	3		4
Total recorded investment	[1]	3	[2]	4
Recorded investment for which there is no related allowance	[1]	$ 3	[2]	$ 4

[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.