Note 6 - Loans and Related Allowance for Loan Losses - Credit Quality Information (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans	$ 781,091	$ 744,392
Pass [Member]
Loans	746,988	702,779
Special Mention [Member]
Loans	26,029	30,661
Substandard [Member]
Loans	6,844	8,963
Doubtful [Member]
Loans	1,230	1,989
Originated Loans [Member]
Loans	657,775	614,898
Originated Loans [Member] | Pass [Member]
Loans	631,029	580,837
Originated Loans [Member] | Special Mention [Member]
Loans	21,104	25,652
Originated Loans [Member] | Substandard [Member]
Loans	4,481	6,497
Originated Loans [Member] | Doubtful [Member]
Loans	1,161	1,912
Acquired Loans [Member]
Loans	123,316	129,494
Acquired Loans [Member] | Pass [Member]
Loans	115,959	121,942
Acquired Loans [Member] | Special Mention [Member]
Loans	4,925	5,009
Acquired Loans [Member] | Substandard [Member]
Loans	2,363	2,466
Acquired Loans [Member] | Doubtful [Member]
Loans	69	77
Residential Portfolio Segment [Member] | Real Estate Sector [Member]
Loans	278,771	273,438
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Pass [Member]
Loans	275,355	270,045
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Special Mention [Member]
Loans	1,015	1,031
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Substandard [Member]
Loans	2,401	2,362
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Doubtful [Member]
Loans
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Loans	209,168	200,486
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Pass [Member]
Loans	207,603	198,869
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Special Mention [Member]
Loans	1,015	1,031
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Substandard [Member]
Loans	550	586
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Doubtful [Member]
Loans
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Loans	69,603	72,952
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Pass [Member]
Loans	67,752	71,176
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Special Mention [Member]
Loans
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Substandard [Member]
Loans	1,851	1,776
Residential Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Doubtful [Member]
Loans
Commercial Portfolio Segment [Member] | Real Estate Sector [Member]
Loans	251,189	209,037
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Pass [Member]
Loans	233,526	187,121
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Special Mention [Member]
Loans	14,581	18,165
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Substandard [Member]
Loans	2,839	3,217
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Doubtful [Member]
Loans	243	534
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Loans	205,929	160,235
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Pass [Member]
Loans	193,686	143,824
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Special Mention [Member]
Loans	9,657	13,161
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Substandard [Member]
Loans	2,343	2,716
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Doubtful [Member]
Loans	243	534
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Loans	45,260	48,802
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Pass [Member]
Loans	39,840	43,297
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Special Mention [Member]
Loans	4,924	5,004
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Substandard [Member]
Loans	496	501
Commercial Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Doubtful [Member]
Loans
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Loans	95,238	107,835
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Pass [Member]
Loans	82,840	92,180
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Special Mention [Member]
Loans	10,433	11,465
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Substandard [Member]
Loans	1,021	2,778
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Doubtful [Member]
Loans	944	1,412
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member]
Loans	86,972	100,294
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member] | Pass [Member]
Loans	74,660	84,910
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member] | Special Mention [Member]
Loans	10,432	11,460
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member] | Substandard [Member]
Loans	1,005	2,589
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Originated Loans [Member] | Doubtful [Member]
Loans	875	1,335
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member]
Loans	8,266	7,541
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member] | Pass [Member]
Loans	8,180	7,270
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member] | Special Mention [Member]
Loans	1	5
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member] | Substandard [Member]
Loans	16	189
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Acquired Loans [Member] | Doubtful [Member]
Loans	69	77
Construction Portfolio Segment [Member] | Real Estate Sector [Member]
Loans	24,587	36,149
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Pass [Member]
Loans		35,571
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Special Mention [Member]
Loans
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Substandard [Member]
Loans		535
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Doubtful [Member]
Loans		43
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member]
Loans	24,587	36,149
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Pass [Member]
Loans	24,024	35,571
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Special Mention [Member]
Loans
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Substandard [Member]
Loans	520	535
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Originated Loans [Member] | Doubtful [Member]
Loans	43	43
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member]
Loans	24,587	36,149
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Pass [Member]
Loans	24,024
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Special Mention [Member]
Loans
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Substandard [Member]
Loans	520
Construction Portfolio Segment [Member] | Real Estate Sector [Member] | Acquired Loans [Member] | Doubtful [Member]
Loans	43
Consumer Portfolio Segment [Member]
Loans	115,972	114,557
Consumer Portfolio Segment [Member] | Pass [Member]
Loans	115,909	114,486
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans	63	71
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans
Consumer Portfolio Segment [Member] | Originated Loans [Member]
Loans	115,785	114,358
Consumer Portfolio Segment [Member] | Originated Loans [Member] | Pass [Member]
Loans	115,722	114,287
Consumer Portfolio Segment [Member] | Originated Loans [Member] | Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] | Originated Loans [Member] | Substandard [Member]
Loans	63	71
Consumer Portfolio Segment [Member] | Originated Loans [Member] | Doubtful [Member]
Loans
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Loans	187	199
Consumer Portfolio Segment [Member] | Acquired Loans [Member] | Pass [Member]
Loans	187	199
Consumer Portfolio Segment [Member] | Acquired Loans [Member] | Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] | Acquired Loans [Member] | Substandard [Member]
Loans
Consumer Portfolio Segment [Member] | Acquired Loans [Member] | Doubtful [Member]
Loans
Other Portfolio Segment [Member]
Loans	15,334	3,376
Other Portfolio Segment [Member] | Pass [Member]
Loans	15,334	3,376
Other Portfolio Segment [Member] | Special Mention [Member]
Loans
Other Portfolio Segment [Member] | Substandard [Member]
Loans
Other Portfolio Segment [Member] | Doubtful [Member]
Loans
Other Portfolio Segment [Member] | Originated Loans [Member]
Loans	15,334	3,376
Other Portfolio Segment [Member] | Originated Loans [Member] | Pass [Member]
Loans	15,334	3,376
Other Portfolio Segment [Member] | Originated Loans [Member] | Special Mention [Member]
Loans
Other Portfolio Segment [Member] | Originated Loans [Member] | Substandard [Member]
Loans
Other Portfolio Segment [Member] | Originated Loans [Member] | Doubtful [Member]
Loans