Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans and Associated Reserves (Details) - USD ($) $ in Thousands		Mar. 31, 2019		Dec. 31, 2018		Mar. 31, 2018
Principal balance		$ 6,759		$ 7,211
Total recorded investment		6,337	[1]	6,820	[1]	$ 11,681
Recorded investment for which there is no related allowance		5,212	[1]	5,667	[1]	10,233
Recorded investment for which there is a related allowance		1,125	[1]	1,153	[1]	1,448
Related allowance		132		139		169
Impaired loans with no valuation allowance		5,212	[1]	5,667	[1]	10,233
Impaired loans with a valuation allowance		1,125	[1]	1,153	[1]	$ 1,448
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Principal balance	[2]	493		728
Total recorded investment	[1],[2]	478		719
Recorded investment for which there is no related allowance	[1],[2]	478		719
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[2]
Impaired loans with no valuation allowance	[1],[2]	478		719
Impaired loans with a valuation allowance	[1],[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Principal balance	[2]	139		144
Total recorded investment	[1],[2]	139		143
Recorded investment for which there is no related allowance	[1],[2]	0		0
Recorded investment for which there is a related allowance	[1],[2]	139		143
Related allowance	[2]	3		4
Impaired loans with no valuation allowance	[1],[2]	0		0
Impaired loans with a valuation allowance	[1],[2]	139		143
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Principal balance	[2]	580		593
Total recorded investment	[1],[2]	570		590
Recorded investment for which there is no related allowance	[1],[2]	570		590
Recorded investment for which there is a related allowance	[1],[2]	0
Related allowance	[2]	0
Impaired loans with no valuation allowance	[1],[2]	570		590
Impaired loans with a valuation allowance	[1],[2]	0
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Principal balance	[2]	476		485
Total recorded investment	[1],[2]	469		483
Recorded investment for which there is no related allowance	[1],[2]	469		483
Recorded investment for which there is a related allowance	[1],[2]			0
Related allowance	[2]	0		0
Impaired loans with no valuation allowance	[1],[2]	469		483
Impaired loans with a valuation allowance	[1],[2]			0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Principal balance	[2]	1,201		1,363
Total recorded investment	[1],[2]	1,199		1,363
Recorded investment for which there is no related allowance	[1],[2]	1,199		1,363
Recorded investment for which there is a related allowance	[1],[2]	0
Related allowance	[2]	0
Impaired loans with no valuation allowance	[1],[2]	1,199		1,363
Impaired loans with a valuation allowance	[1],[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]	2,483		2,494
Recorded investment for which there is no related allowance	[1],[2]	2,483		2,494
Recorded investment for which there is a related allowance	[1],[2]	0		0
Related allowance	[2]	0		0
Impaired loans with no valuation allowance	[1],[2]	2,483		2,494
Impaired loans with a valuation allowance	[1],[2]	0		0
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Principal balance	[2]	993		1,018
Total recorded investment	[1],[2]	989		1,015
Recorded investment for which there is no related allowance	[1],[2]	3		5
Recorded investment for which there is a related allowance	[1],[2]	986		1,010
Related allowance	[2]	129		135
Impaired loans with no valuation allowance	[1],[2]	3		5
Impaired loans with a valuation allowance	[1],[2]	986		1,010
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Principal balance	[2]	10		13
Total recorded investment	[1],[2]	10		13
Recorded investment for which there is no related allowance	[1],[2]	10		13
Recorded investment for which there is a related allowance	[1],[2]
Related allowance	[2]	0
Impaired loans with no valuation allowance	[1],[2]	10		13
Impaired loans with a valuation allowance	[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.