Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2020		Dec. 31, 2019		Mar. 31, 2019
Loans past due 90 days or more and still accruing		$ 170	[1]	$ 231	[1]	$ 55
Nonaccruals		3,452	[1]	3,375	[1],[2]	$ 3,734
Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due 90 days or more and still accruing	[1]
Nonaccruals	[1]	21
Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Loans past due 90 days or more and still accruing	[1]
Nonaccruals	[1]
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due 90 days or more and still accruing	[1]	54		188
Nonaccruals	[1]	104		22	[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due 90 days or more and still accruing	[1]	83
Nonaccruals	[1]	0		0	[2]
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]	263		264	[2]
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due 90 days or more and still accruing	[1]			0
Nonaccruals	[1],[2]
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]	510		514	[2]
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]	2,419		2,435	[2]
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due 90 days or more and still accruing	[1]			17
Nonaccruals	[1]	132		136	[2]
Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due 90 days or more and still accruing	[1]
Nonaccruals	[1]	0		0	[2]
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due 90 days or more and still accruing	[1]	22		14
Nonaccruals	[1]			4	[2]
Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due 90 days or more and still accruing	[1]	11		12
Nonaccruals	[1]	3			[2]
Financing Receivables 30 to 89 Days Past Due [Member]
Loans past due and accruing	[1]	2,853		1,070
Financing Receivables 30 to 89 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due and accruing	[1]			19
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Loans past due and accruing	[1]	106
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]	990		499
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]			83
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]	109
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]			94
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]
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]	838		0
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]	412		45
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]	2		4
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]	293		256
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]	103		70
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due and accruing	[1]	979		940
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due and accruing	[1]	21
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [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]	158		210
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]	83
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]	264		264
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]
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]	287		287
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 Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	[1]	133		153
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]
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]	22		14
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]	$ 11		$ 12

[1] Only classes with past due or nonaccrual loans are presented

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