Note 6 - Loans and the Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans	$ 975,284	$ 810,951
Pass [Member]
Loans	924,290	753,753
Special Mention [Member]
Loans	32,824	37,533
Substandard [Member]
Loans	5,635	12,539
Doubtful [Member]
Loans	12,535	7,126
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Loans	143,535	94,426
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Pass [Member]
Loans	141,128	92,951
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Special Mention [Member]
Loans	1,953	932
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Substandard [Member]
Loans	362	300
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Doubtful [Member]
Loans	92	243
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	10,480	9,217
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Loans	10,480	9,217
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	337,699	298,057
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Loans	325,216	280,398
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Loans	4,861	14,531
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Loans	1,687	1,927
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Doubtful [Member]
Loans	5,935	1,201
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Loans	157,505	129,052
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Pass [Member]
Loans	148,845	118,891
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Special Mention [Member]
Loans	4,657	4,782
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Substandard [Member]
Loans	1,574	2,658
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Doubtful [Member]
Loans	2,429	2,721
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Loans	20,717	22,737
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Pass [Member]
Loans	20,677	22,685
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	40	52
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Doubtful [Member]
Loans	0	0
Commercial Portfolio Segment [Member]
Loans	254,427	213,120
Commercial Portfolio Segment [Member] | Pass [Member]
Loans	228,157	186,197
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans	20,681	16,783
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans	1,951	7,377
Commercial Portfolio Segment [Member] | Doubtful [Member]
Loans	3,638	2,763
Consumer Portfolio Segment [Member]
Loans	50,921	44,342
Consumer Portfolio Segment [Member] | Pass [Member]
Loans	49,787	43,414
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans	672	505
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans	21	225
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans	$ 441	$ 198