Note 8 - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	$ 6,636	$ 5,941
Loans current	823,689	779,267
Loans and leases receivable	830,325	785,208
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	1,586	1,072
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	2,199	2,007
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	2,851	2,862
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	2,116	1,607
Loans current	159,753	160,845
Loans and leases receivable	161,869	162,452
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	27	94
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	265	141
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	1,824	1,372
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Loans current	53,450	50,135
Loans and leases receivable	53,450	50,135
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Commercial Portfolio Segment [Member] | Secured by Commercial Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	2,253	1,972
Loans current	337,855	306,618
Loans and leases receivable	340,108	308,590
Commercial Portfolio Segment [Member] | Secured by Commercial Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	506	305
Commercial Portfolio Segment [Member] | Secured by Commercial Real Estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	1,412	1,029
Commercial Portfolio Segment [Member] | Secured by Commercial Real Estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	335	638
Commercial Portfolio Segment [Member] | Secured by Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	606	667
Loans current	72,515	67,914
Loans and leases receivable	73,121	68,581
Commercial Portfolio Segment [Member] | Secured by Residential Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	274	24
Commercial Portfolio Segment [Member] | Secured by Residential Real Estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	87	352
Commercial Portfolio Segment [Member] | Secured by Residential Real Estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	245	291
State and Political Subdivisions Portfolio Segment [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Loans current	54,684	43,737
Loans and leases receivable	54,684	43,737
State and Political Subdivisions Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
State and Political Subdivisions Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
State and Political Subdivisions Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	0
Retail Portfolio Segment [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	35	82
Loans current	6,602	6,703
Loans and leases receivable	6,637	6,785
Retail Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	24	23
Retail Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	11	35
Retail Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	24
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	829	1,265
Loans current	67,060	66,188
Loans and leases receivable	67,889	67,453
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	0	544
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	388	245
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	441	476
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	797	348
Loans current	71,770	77,127
Loans and leases receivable	72,567	77,475
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	755	82
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	36	205
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Loans past due	$ 6	$ 61