Note 6 - Loans and the Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans	$ 1,191,450	$ 975,284
Pass [Member]
Loans	1,134,020	924,290
Special Mention [Member]
Loans	29,030	32,824
Substandard [Member]
Loans	13,367	5,635
Doubtful [Member]
Loans	15,033	12,535
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Loans	191,220	143,535
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Pass [Member]
Loans	188,819	141,128
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Special Mention [Member]
Loans	1,940	1,953
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Substandard [Member]
Loans	357	362
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Doubtful [Member]
Loans	104	92
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	14,498	10,480
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Loans	14,498	10,480
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Special Mention [Member]
Loans	0	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	390,478	337,699
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Loans	370,922	325,216
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Loans	5,495	4,861
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Loans	5,998	1,687
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Doubtful [Member]
Loans	8,063	5,935
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Loans	218,623	157,505
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Pass [Member]
Loans	208,903	148,845
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Special Mention [Member]
Loans	5,008	4,657
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Substandard [Member]
Loans	1,951	1,574
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Doubtful [Member]
Loans	2,761	2,429
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Loans	25,884	20,717
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Pass [Member]
Loans	25,845	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	39	40
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Doubtful [Member]
Loans	0	0
Commercial Portfolio Segment [Member]
Loans	290,427	254,427
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	265,816	228,157
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans	15,900	20,681
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans	4,954	1,951
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans	3,757	3,638
Consumer Portfolio Segment [Member]
Loans	60,320	50,921
Consumer Portfolio Segment [Member] | Pass [Member]
Loans	59,217	49,787
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans	687	672
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans	68	21
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans	$ 348	$ 441