Note 4 - Loans - Performing and Non-performing Loan Delinquency Status (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Loans past due	$ 834,347	$ 835,207
Performing Financial Instruments [Member]
Loans past due	828,228	830,511
Nonperforming Financial Instruments [Member]
Loans past due	6,119	4,696
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	164,442	164,145
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	1,408	688
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	276,261	259,904
Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	39,371	20,813
Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Commercial and Industrial [Member] | Performing Financial Instruments [Member]
Loans past due	162,712	150,215
Commercial and Industrial [Member] | Nonperforming Financial Instruments [Member]
Loans past due	752	747
Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans past due	147,806	176,397
Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans past due	629	387
State and Political Subdivisions [Member] | Performing Financial Instruments [Member]
Loans past due	37,636	59,037
State and Political Subdivisions [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	3,330	2,874
Financial Asset, 1 to 29 Days Past Due [Member]
Loans past due	827,079	829,714
Financial Asset, 1 to 29 Days Past Due [Member] | Performing Financial Instruments [Member]
Loans past due	824,681	827,442
Financial Asset, 1 to 29 Days Past Due [Member] | Nonperforming Financial Instruments [Member]
Loans past due	2,398	2,272
Financial Asset, 1 to 29 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	163,591	163,690
Financial Asset, 1 to 29 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	552	443
Financial Asset, 1 to 29 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	275,847	259,904
Financial Asset, 1 to 29 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	39,371	20,813
Financial Asset, 1 to 29 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 1 to 29 Days Past Due [Member] | Commercial and Industrial [Member] | Performing Financial Instruments [Member]
Loans past due	162,247	150,108
Financial Asset, 1 to 29 Days Past Due [Member] | Commercial and Industrial [Member] | Nonperforming Financial Instruments [Member]
Loans past due	487	677
Financial Asset, 1 to 29 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans past due	145,989	173,890
Financial Asset, 1 to 29 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans past due	226	91
Financial Asset, 1 to 29 Days Past Due [Member] | State and Political Subdivisions [Member] | Performing Financial Instruments [Member]
Loans past due	37,636	59,037
Financial Asset, 1 to 29 Days Past Due [Member] | State and Political Subdivisions [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 1 to 29 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	1,133	1,061
Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	2,686	2,738
Financial Asset, 30 to 59 Days Past Due [Member] | Performing Financial Instruments [Member]
Loans past due	2,613	2,627
Financial Asset, 30 to 59 Days Past Due [Member] | Nonperforming Financial Instruments [Member]
Loans past due	73	111
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	851	319
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due		0
Financial Asset, 30 to 59 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and Industrial [Member] | Performing Financial Instruments [Member]
Loans past due	262	87
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and Industrial [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	50
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans past due	1,500	2,221
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans past due	73	61
Financial Asset, 30 to 59 Days Past Due [Member] | State and Political Subdivisions [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | State and Political Subdivisions [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	1,515	652
Financial Asset, 60 to 89 Days Past Due [Member] | Performing Financial Instruments [Member]
Loans past due	934	442
Financial Asset, 60 to 89 Days Past Due [Member] | Nonperforming Financial Instruments [Member]
Loans past due	581	210
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due		136
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	136
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	414	0
Financial Asset, 60 to 89 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and Industrial [Member] | Performing Financial Instruments [Member]
Loans past due	203	20
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and Industrial [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans past due	317	286
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans past due	153	74
Financial Asset, 60 to 89 Days Past Due [Member] | State and Political Subdivisions [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | State and Political Subdivisions [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	428	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	3,067	2,103
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Nonperforming Financial Instruments [Member]
Loans past due	3,067	2,103
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	856	109
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction, Land Acquisition and Development [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Industrial [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Industrial [Member] | Nonperforming Financial Instruments [Member]
Loans past due	265	20
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans past due	177	161
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | State and Political Subdivisions [Member] | Performing Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | State and Political Subdivisions [Member] | Nonperforming Financial Instruments [Member]
Loans past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member] | Nonperforming Financial Instruments [Member]
Loans past due	$ 1,769	$ 1,813