Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2019		Dec. 31, 2018		Mar. 31, 2018
Loans past due 90 days or more and still accruing		$ 55	[1]	$ 35	[1]	$ 52
Nonaccruals		3,734	[1],[2]	3,420	[1],[2]	$ 2,764
Construction, Other [Member] | Equity Lines [Member]
Loans past due 90 days or more and still accruing	[1]
Nonaccruals	[1],[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due 90 days or more and still accruing	[1]	19
Nonaccruals	[1],[2]	270		278
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due 90 days or more and still accruing	[1]	0
Nonaccruals	[1],[2]	0		0
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Loans past due 90 days or more and still accruing	[1]	0		0
Nonaccruals	[1],[2]	240		451
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due 90 days or more and still accruing	[1]	0		0
Nonaccruals	[1],[2]	181		192
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Loans past due 90 days or more and still accruing	[1]	0		0
Nonaccruals	[1],[2]	560
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans past due 90 days or more and still accruing	[1]	0		0
Nonaccruals	[1],[2]	2,483		2,494
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due 90 days or more and still accruing	[1]			2
Nonaccruals	[1],[2]			5
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due 90 days or more and still accruing	[1]	1
Nonaccruals	[1],[2]
Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due 90 days or more and still accruing	[1]	3
Nonaccruals	[1],[2]	0		0
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due 90 days or more and still accruing	[1]	31		29
Nonaccruals	[1],[2]
Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due 90 days or more and still accruing	[1]	1		4
Nonaccruals	[1],[2]	0		0
Financing Receivables 30 to 89 Days Past Due [Member]
Loans past due and accruing	[1]	1,822		1,635
Financing Receivables 30 to 89 Days Past Due [Member] | Construction, Other [Member] | Equity Lines [Member]
Loans past due and accruing	[1]	20
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due and accruing	[1]	1,225		647
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due and accruing	[1]	176		11
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Loans past due and accruing	[1]
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due and accruing	[1]			291
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Loans past due and accruing	[1]			325
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans past due and accruing	[1]	0		0
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	[1]			10
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	[1]	91
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due and accruing	[1]	6		5
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due and accruing	[1]	261		296
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due and accruing	[1]	43		50
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due and accruing	[1]	579		346
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction, Other [Member] | Equity Lines [Member]
Loans past due and accruing	[1]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due and accruing	[1]	41		119
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due and accruing	[1]	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Loans past due and accruing	[1]	240
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due and accruing	[1]			192
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Loans past due and accruing	[1]	262
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans past due and accruing	[1]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	[1]			2
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	[1]	1
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due and accruing	[1]	3
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due and accruing	[1]	31		29
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due and accruing	[1]	$ 1		$ 4

[1] Only classes with past-due or nonaccrual loans are shown.

[2] Includes current and past due loans in nonaccrual status. Includes impaired loans in nonaccrual status.