Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans and Associated Reserves (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Principal balance		$ 5,757	$ 7,211
Total recorded investment	[1]	5,289	6,820
Recorded investment for which there is no related allowance	[1]	4,174	5,667
Recorded investment for which there is a related allowance	[1]	1,115	1,153
Related allowance		110	139
Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Principal balance	[2]	100
Total recorded investment	[1],[2]	100
Recorded investment for which there is no related allowance	[1],[2]	100
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Principal balance	[2]	221	728
Total recorded investment	[1],[2]	221	719
Recorded investment for which there is no related allowance	[1],[2]	221	719
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Principal balance	[2]		144
Total recorded investment	[1],[2]		143
Recorded investment for which there is no related allowance	[1],[2]		0
Recorded investment for which there is a related allowance	[1],[2]		143
Related allowance	[2]		4
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Principal balance	[2]	441	593
Total recorded investment	[1],[2]	438	590
Recorded investment for which there is no related allowance	[1],[2]	241	590
Recorded investment for which there is a related allowance	[1],[2]	197
Related allowance	[2]	2
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Principal balance	[2]	278	485
Total recorded investment	[1],[2]	278	483
Recorded investment for which there is no related allowance	[1],[2]	278	483
Recorded investment for which there is a related allowance	[1],[2]		0
Related allowance	[2]	0	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Principal balance	[2]	929	1,363
Total recorded investment	[1],[2]	895	1,363
Recorded investment for which there is no related allowance	[1],[2]	895	1,363
Recorded investment for which there is a related allowance	[1],[2]	0
Related allowance	[2]	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Principal balance	[2]	2,867	2,867
Total recorded investment	[1],[2]	2,435	2,494
Recorded investment for which there is no related allowance	[1],[2]	2,435	2,494
Recorded investment for which there is a related allowance	[1],[2]	0	0
Related allowance	[2]	0	0
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Principal balance	[2]	917	1,018
Total recorded investment	[1],[2]	918	1,015
Recorded investment for which there is no related allowance	[1],[2]		5
Recorded investment for which there is a related allowance	[1],[2]	918	1,010
Related allowance	[2]	108	135
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Principal balance	[2]	4	13
Total recorded investment	[1],[2]	4	13
Recorded investment for which there is no related allowance	[1],[2]	4	13
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[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.