Note 5 - Loans Receivable (Details) - Loans by Risk Categories (USD $)	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 1,055,117,000	$ 383,938,000
One-to-Four-Family Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	231,002,000	34,333,000
One-to-Four-Family Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,833,000	329,000
One-to-Four-Family Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	11,792,000	6,371,000
One-to-Four-Family Residential [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	75,862,000	88,275,000
One-to-Four-Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	320,489,000	129,308,000
Multifamily Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	45,181,000	25,773,000
Multifamily Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	45,181,000	25,773,000
Nonfarm Nonresidential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	349,672,000	159,629,000
Nonfarm Nonresidential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	4,378,000	4,490,000
Nonfarm Nonresidential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	15,585,000	4,057,000
Nonfarm Nonresidential [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	339,000	726,000
Nonfarm Nonresidential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	369,974,000	168,902,000
Farmland [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	46,002,000	1,491,000
Farmland [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,197,000	1,172,000
Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	47,199,000	2,663,000
Construction and Land Development [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	93,841,000	18,241,000
Construction and Land Development [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	105,000	295,000
Construction and Land Development [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,375,000	2,770,000
Construction and Land Development [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,273,000	2,585,000
Construction and Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	98,594,000	23,891,000
Commercial Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	135,547,000	28,555,000
Commercial Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	4,059,000	350,000
Commercial Loans [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	265,000	128,000
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	139,871,000	29,033,000
Consumer Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	27,702,000	151,000
Consumer Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	6,000
Consumer Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	191,000	45,000
Consumer Loans [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	5,910,000	4,172,000
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	33,809,000	4,368,000
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	928,947,000	268,173,000
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	6,322,000	5,114,000
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	35,199,000	14,765,000
Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 84,649,000	$ 95,886,000