Note 4 - Loans and Related Allowance for Loan Loss - Loans Summarized by Individually Evaluated for Impairment and Collectively Evaluated for Potential Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Individually Evaluated for Impairment	$ 9,156	$ 9,701
Collectively Evaluated for Potential Impairment	694,718	672,196
Total Loans	703,874	681,897
Originated Loans [Member]
Individually Evaluated for Impairment	6,597	6,832
Collectively Evaluated for Potential Impairment	560,507	518,520
Total Loans	567,104	525,352
Acquired Loans [Member]
Individually Evaluated for Impairment	2,559	2,869
Collectively Evaluated for Potential Impairment	134,211	153,676
Total Loans	136,770	156,545
Residential Portfolio Segment [Member] | Real Estate Sector [Member]
Individually Evaluated for Impairment	1,392	1,300
Collectively Evaluated for Potential Impairment	267,039	270,288
Total Loans	268,431	271,588
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Individually Evaluated for Impairment	124
Collectively Evaluated for Potential Impairment	193,090	186,077
Total Loans	193,214	186,077
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment	1,268	1,300
Collectively Evaluated for Potential Impairment	73,949	84,211
Total Loans	75,217	85,511
Commercial Portfolio Segment [Member] | Real Estate Sector [Member]
Individually Evaluated for Impairment	4,325	4,368
Collectively Evaluated for Potential Impairment	198,943	196,642
Total Loans	203,268	201,010
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Individually Evaluated for Impairment	3,381	3,361
Collectively Evaluated for Potential Impairment	147,061	136,533
Total Loans	150,442	139,894
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment	944	1,007
Collectively Evaluated for Potential Impairment	51,882	60,109
Total Loans	52,826	61,116
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Individually Evaluated for Impairment	2,828	3,327
Collectively Evaluated for Potential Impairment	82,921	77,485
Total Loans	85,749	80,812
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member]
Individually Evaluated for Impairment	2,481	2,765
Collectively Evaluated for Potential Impairment	74,736	68,326
Total Loans	77,217	71,091
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment	347	562
Collectively Evaluated for Potential Impairment	8,185	9,159
Total Loans	8,532	9,721
Construction Portfolio Segment [Member] | Real Estate Sector [Member]
Individually Evaluated for Impairment	609	702
Collectively Evaluated for Potential Impairment	28,356	9,944
Total Loans	28,965	10,646
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Individually Evaluated for Impairment	609	702
Collectively Evaluated for Potential Impairment	28,356	9,944
Total Loans	28,965	10,646
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Total Loans
Consumer Portfolio Segment [Member]
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	114,017	114,204
Total Loans	114,017	114,204
Consumer Portfolio Segment [Member] | Originated Loans [Member]
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	113,822	114,007
Total Loans	113,822	114,007
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	195	197
Total Loans	195	197
Other Portfolio Segment [Member]
Individually Evaluated for Impairment	2	4
Collectively Evaluated for Potential Impairment	3,442	3,633
Total Loans	3,444	3,637
Other Portfolio Segment [Member] | Originated Loans [Member]
Individually Evaluated for Impairment	2	4
Collectively Evaluated for Potential Impairment	3,442	3,633
Total Loans	3,444	3,637
Other Portfolio Segment [Member] | Acquired Loans [Member]
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Total Loans