Note 5 - Allowance for Loan Losses - Loans by Internal Risk Rating (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans receivable	$ 1,162,049	$ 965,044
Pass [Member]
Loans receivable	1,142,559	940,549
Special Mention [Member]
Loans receivable	1,226	1,994
Substandard [Member]
Loans receivable	17,984	21,072
Doubtful [Member]
Loans receivable	280	1,429
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	433,304	378,519
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Loans receivable	423,382	364,066
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Loans receivable	959	877
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Loans receivable	8,963	13,576
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Loans receivable
Construction and Land Development Portfolio Segment [Member]
Loans receivable	104,617	61,453
Construction and Land Development Portfolio Segment [Member] | Pass [Member]
Loans receivable	104,617	61,453
Construction and Land Development Portfolio Segment [Member] | Special Mention [Member]
Loans receivable
Construction and Land Development Portfolio Segment [Member] | Substandard [Member]
Loans receivable
Construction and Land Development Portfolio Segment [Member] | Doubtful [Member]
Loans receivable
Commercial Portfolio Segment [Member]
Loans receivable	173,343	174,744
Commercial Portfolio Segment [Member] | Pass [Member]
Loans receivable	168,702	168,958
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans receivable	140	606
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans receivable	4,221	3,751
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans receivable	280	1,429
Owner Occupied Real Estate [Member]
Loans receivable	309,838	276,986
Owner Occupied Real Estate [Member] | Pass [Member]
Loans receivable	306,040	274,150
Owner Occupied Real Estate [Member] | Special Mention [Member]
Loans receivable		511
Owner Occupied Real Estate [Member] | Substandard [Member]
Loans receivable	3,798	2,325
Owner Occupied Real Estate [Member] | Doubtful [Member]
Loans receivable
Consumer Portfolio Segment [Member]
Loans receivable	76,183	63,660
Consumer Portfolio Segment [Member] | Pass [Member]
Loans receivable	75,181	62,370
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans receivable
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans receivable	1,002	1,290
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans receivable
Residential Portfolio Segment [Member]
Loans receivable	64,764	9,682
Residential Portfolio Segment [Member] | Pass [Member]
Loans receivable	64,637	9,552
Residential Portfolio Segment [Member] | Special Mention [Member]
Loans receivable	127
Residential Portfolio Segment [Member] | Substandard [Member]
Loans receivable		130
Residential Portfolio Segment [Member] | Doubtful [Member]
Loans receivable