Note 5 - Loans Receivable (Details) - Past Due and Nonaccrual Loans - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	$ 1,440,727	$ 1,037,948
Loans receivable, total	1,458,094	1,055,117
Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	9,637	9,354
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	7,730	7,815
Nonaccrual [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	11,508	3,315
Loans receivable, total	19,340	9,770
Nonaccrual [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	1,598	1,257
Nonaccrual [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	6,234	5,198
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	391,622	311,978
Loans receivable, total	401,036	320,489
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	6,051	4,966
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	3,363	3,545
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	74,034	45,181
Loans receivable, total	74,226	45,181
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	125
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	67
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	483,978	364,175
Loans receivable, total	487,684	369,974
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	1,060	3,350
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	2,646	2,449
Real Estate Portfolio Segment [Member] | Farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	93,525	46,556
Loans receivable, total	94,235	47,199
Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	42	15
Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	668	628
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	115,357	97,818
Loans receivable, total	116,015	98,594
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	148	127
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	510	649
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | One-to-Four-Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	2,168	1,266
Loans receivable, total	6,455	4,959
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | One-to-Four-Family Residential [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	1,419	1,121
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | One-to-Four-Family Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	2,868	2,572
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Multifamily Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	163
Loans receivable, total	230
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Multifamily Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	67
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Nonfarm Nonresidential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	4,760	1,603
Loans receivable, total	6,638	3,113
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	136	131
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Nonfarm Nonresidential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	1,742	1,379
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	305	106
Loans receivable, total	973	734
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Farmland [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	668	628
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	184	19
Loans receivable, total	622	624
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Construction Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	6
Real Estate Portfolio Segment [Member] | Nonaccrual [Member] | Construction Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	432	605
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	244,246	138,857
Loans receivable, total	246,304	139,871
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	1,722	517
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	336	497
Commercial Portfolio Segment [Member] | Nonaccrual [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	3,887	306
Loans receivable, total	4,235	306
Commercial Portfolio Segment [Member] | Nonaccrual [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	23
Commercial Portfolio Segment [Member] | Nonaccrual [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	325
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	37,965	33,383
Loans receivable, total	38,594	33,809
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	489	379
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	140	47
Consumer Portfolio Segment [Member] | Nonaccrual [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, current	41	15
Loans receivable, total	187	34
Consumer Portfolio Segment [Member] | Nonaccrual [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	14	5
Consumer Portfolio Segment [Member] | Nonaccrual [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable, past due	$ 132	$ 14