Note 6 - Loans and the Allowance for Loan Losses - Summary of Credit Quality Indicators, Disaggregated by Class of Loan (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Credit quality indicators	$ 874,506	$ 810,951
Pass [Member]
Credit quality indicators	816,138	753,753
Special Mention [Member]
Credit quality indicators	39,716	37,533
Substandard [Member]
Credit quality indicators	7,547	12,539
Doubtful [Member]
Credit quality indicators	11,105	7,126
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Credit quality indicators	112,199	94,426
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Pass [Member]
Credit quality indicators	109,643	92,951
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Special Mention [Member]
Credit quality indicators	2,001	932
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Substandard [Member]
Credit quality indicators	409	300
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Doubtful [Member]
Credit quality indicators	146	243
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Credit quality indicators	10,524	9,217
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Credit quality indicators	10,524	9,217
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Special Mention [Member]
Credit quality indicators	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Substandard [Member]
Credit quality indicators	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Doubtful [Member]
Credit quality indicators	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Credit quality indicators	304,278	298,057
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Credit quality indicators	288,548	280,398
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Credit quality indicators	10,561	14,531
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Credit quality indicators	1,765	1,927
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Doubtful [Member]
Credit quality indicators	3,404	1,201
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Credit quality indicators	139,398	129,052
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Pass [Member]
Credit quality indicators	129,819	118,891
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Special Mention [Member]
Credit quality indicators	5,270	4,782
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Substandard [Member]
Credit quality indicators	1,916	2,658
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Doubtful [Member]
Credit quality indicators	2,393	2,721
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Credit quality indicators	23,039	22,737
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Pass [Member]
Credit quality indicators	22,997	22,685
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Special Mention [Member]
Credit quality indicators	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Substandard [Member]
Credit quality indicators	42	52
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Doubtful [Member]
Credit quality indicators	0	0
Commercial Portfolio Segment [Member]
Credit quality indicators	238,924	213,120
Commercial Portfolio Segment [Member] | Pass [Member]
Credit quality indicators	209,394	186,197
Commercial Portfolio Segment [Member] | Special Mention [Member]
Credit quality indicators	21,211	16,783
Commercial Portfolio Segment [Member] | Substandard [Member]
Credit quality indicators	3,392	7,377
Commercial Portfolio Segment [Member] | Doubtful [Member]
Credit quality indicators	4,927	2,763
Consumer Portfolio Segment [Member]
Credit quality indicators	46,144	44,342
Consumer Portfolio Segment [Member] | Pass [Member]
Credit quality indicators	45,213	43,414
Consumer Portfolio Segment [Member] | Special Mention [Member]
Credit quality indicators	673	505
Consumer Portfolio Segment [Member] | Substandard [Member]
Credit quality indicators	23	225
Consumer Portfolio Segment [Member] | Doubtful [Member]
Credit quality indicators	$ 235	$ 198