Note 4 - Loans and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans past due	$ 13,846	$ 12,190
Loans, current	766,798	764,862
Loans	780,644	777,052
Residential Portfolio Segment [Member]
Loans past due	6,814	6,194
Loans, current	295,577	297,885
Loans	302,391	304,079
Commercial Real Estate Portfolio Segment [Member]
Loans	223,506	216,360
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	1,193	427
Loans, current	63,360	61,267
Loans	64,553	61,694
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	1,383	1,046
Loans, current	125,722	116,142
Loans	127,105	117,188
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	182	296
Loans, current	31,666	37,182
Loans	31,848	37,478
Commercial and Industrial Portfolio Segment [Member]
Loans past due	1,136	730
Loans, current	113,619	112,513
Loans	114,755	113,243
Consumer Portfolio Segment [Member]
Loans	139,992	143,370
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	1,820	1,862
Loans, current	65,179	68,364
Loans	66,999	70,226
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	324	523
Loans, current	22,891	21,989
Loans	23,215	22,512
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	994	1,112
Loans, current	48,784	49,520
Loans	49,778	50,632
Financial Asset, 30 to 59 Days Past Due [Member]
Loans past due	8,426	6,476
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	3,516	3,369
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	953	298
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	714	299
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due		31
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	1,024	428
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	1,386	1,287
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	162	171
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	671	593
Financial Asset, 60 to 89 Days Past Due [Member]
Loans past due	2,629	2,044
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	1,809	1,183
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	151
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	61
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	112	192
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	274	286
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due		92
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	222	291
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans past due	2,791	3,670
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	1,489	1,642
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	89	129
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	669	747
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	121	265
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due		110
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	160	289
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	162	260
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	$ 101	$ 228