Note 6 - Loans and the Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans	$ 1,297,959	$ 975,284
Pass [Member]
Loans	1,252,415	924,290
Special Mention [Member]
Loans	16,424	32,824
Substandard [Member]
Loans	17,779	5,635
Doubtful [Member]
Loans	11,341	12,535
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Loans	196,404	143,535
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Pass [Member]
Loans	193,894	141,128
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Special Mention [Member]
Loans	1,208	1,953
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Substandard [Member]
Loans	1,295	362
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Doubtful [Member]
Loans	7	92
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	26,882	10,480
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Loans	26,880	10,480
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Special Mention [Member]
Loans	2	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Substandard [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Doubtful [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Loans	432,306	337,699
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Loans	414,530	325,216
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Loans	5,786	4,861
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Loans	5,926	1,687
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Doubtful [Member]
Loans	6,064	5,935
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Loans	234,690	157,505
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Pass [Member]
Loans	225,196	148,845
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Special Mention [Member]
Loans	4,616	4,657
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Substandard [Member]
Loans	2,384	1,574
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Doubtful [Member]
Loans	2,494	2,429
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Loans	22,109	20,717
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Pass [Member]
Loans	22,072	20,677
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Special Mention [Member]
Loans	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Substandard [Member]
Loans	37	40
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Doubtful [Member]
Loans	0	0
Commercial Portfolio Segment [Member]
Loans	317,889	254,427
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	303,204	228,157
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans	3,960	20,681
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans	8,052	1,951
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans	2,673	3,638
Consumer Portfolio Segment [Member]
Loans	67,679	50,921
Consumer Portfolio Segment [Member] | Pass [Member]
Loans	66,639	49,787
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans	852	672
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans	85	21
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans	$ 103	$ 441