Note 6 - Loans and the Allowance for Loan Losses - Summary of Aged Analysis of Past Due Loans Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Past Due	$ 11,749	$ 6,071
Current	842,269	804,880
Credit quality indicators	854,018	810,951
Recorded Investment Over 90 Days Past Due and Still Accruing	53	168
Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	4,572	2,935
Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	1,042	1,124
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	6,135	2,012
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member]
Past Due	1,056	571
Current	104,086	93,855
Credit quality indicators	105,142	94,426
Recorded Investment Over 90 Days Past Due and Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	372	465
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	490	0
Commercial Real Estate Portfolio Segment [Member] | Construction and Land [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	194	106
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member]
Past Due	0	0
Current	10,695	9,217
Credit quality indicators	10,695	9,217
Recorded Investment Over 90 Days Past Due and Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Past Due	3,968	2,075
Current	307,096	295,982
Credit quality indicators	311,064	298,057
Recorded Investment Over 90 Days Past Due and Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	1,156	1,370
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	76	173
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	2,736	532
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member]
Past Due	1,739	2,531
Current	127,987	126,521
Credit quality indicators	129,726	129,052
Recorded Investment Over 90 Days Past Due and Still Accruing	0	117
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	560	989
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	476	579
Residential Portfolio Segment [Member] | Real Estate Residential One- to Four-Family [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	703	963
Residential Portfolio Segment [Member] | Multi-family Residential [Member]
Past Due	0	0
Current	23,795	22,737
Credit quality indicators	23,795	22,737
Recorded Investment Over 90 Days Past Due and Still Accruing	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	0	0
Residential Portfolio Segment [Member] | Multi-family Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	0	0
Commercial Portfolio Segment [Member]
Past Due	4,828	679
Current	222,482	212,441
Credit quality indicators	227,310	213,120
Recorded Investment Over 90 Days Past Due and Still Accruing	53	51
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	2,475	45
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	0	372
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	2,353	262
Consumer Portfolio Segment [Member]
Past Due	158	215
Current	46,128	44,127
Credit quality indicators	46,286	44,342
Recorded Investment Over 90 Days Past Due and Still Accruing	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past Due	9	66
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past Due	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past Due	$ 149	$ 149