Note 4 - Loans and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans past due	$ 11,990	$ 14,828
Loans, current	769,990	754,491
Loans	781,980	769,319
Residential Portfolio Segment [Member]
Loans past due	5,291	7,727
Loans, current	300,027	301,436
Loans	305,318	309,163
Commercial Real Estate Portfolio Segment [Member]
Loans	222,535	213,446
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	587	515
Loans, current	65,584	73,058
Loans	66,171	73,573
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	2,392	2,378
Loans, current	114,084	99,193
Loans	116,476	101,571
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	331	169
Loans, current	39,557	38,133
Loans	39,888	38,302
Commercial and Industrial Portfolio Segment [Member]
Loans past due	669	737
Loans, current	114,169	106,352
Loans	114,838	107,089
Consumer Portfolio Segment [Member]
Loans	139,289	139,621
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	1,386	1,754
Loans, current	67,060	66,872
Loans	68,446	68,626
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	415	389
Loans, current	21,825	21,042
Loans	22,240	21,431
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	919	1,159
Loans, current	47,684	48,405
Loans	48,603	49,564
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans past due	5,916	8,232
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	2,599	5,383
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	274	194
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	617	140
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	174
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	404	303
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	1,004	1,257
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	289	90
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	555	865
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	1,311	1,911
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	742	671
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	23	161
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	71	243
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	224	346
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	34	272
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	217	218
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	4,763	4,685
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	1,950	1,673
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	290	160
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	1,775	2,238
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	157	169
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	194	191
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	158	151
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	92	27
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	$ 147	$ 76