Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans past due 90 days or more and still accruing	$ 51	$ 63
Nonaccruals	2,769	5,855
Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	270
Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	0
Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	0
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due 90 days or more and still accruing	11	6
Nonaccruals	145	0
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due 90 days or more and still accruing	0	36
Nonaccruals	0	0
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	6	253
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	1,091
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	1,183
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	2,602	2,814
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due 90 days or more and still accruing	0
Nonaccruals	15
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due 90 days or more and still accruing		0
Nonaccruals		241
Public Sector and IDA Portfolio Segment[Member]
Loans past due 90 days or more and still accruing	0	0
Nonaccruals	0	0
Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due 90 days or more and still accruing	12	5
Nonaccruals	0	0
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due 90 days or more and still accruing	22	12
Nonaccruals	1	3
Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due 90 days or more and still accruing	6	4
Nonaccruals	0	0
Financing Receivables 30 to 89 Days Past Due [Member]
Loans past due and accruing	2,263	2,553
Financing Receivables 30 to 89 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member]
Loans past due and accruing	0	0
Financing Receivables 30 to 89 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due and accruing	0	25
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Loans past due and accruing	0	10
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	637	1,498
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	188	114
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	66	56
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due and accruing	303	132
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	402	339
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	0	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	131
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing		6
Financing Receivables 30 to 89 Days Past Due [Member] | Public Sector and IDA Portfolio Segment[Member]
Loans past due and accruing	0	0
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	7	8
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due and accruing	375	234
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	154	131
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due and accruing	2,658	1,888
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member]
Loans past due and accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member]
Loans past due and accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member]
Loans past due and accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Loans past due and accruing	16	6
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Loans past due and accruing	0	36
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Loans past due and accruing	0	234
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Loans past due and accruing	0	1,091
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Loans past due and accruing	0	202
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans past due and accruing	2,602	80
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due and accruing		218
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Public Sector and IDA Portfolio Segment[Member]
Loans past due and accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member]
Loans past due and accruing	12	5
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due and accruing	22	12
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due and accruing	$ 6	$ 4