Note 5 - Loans Receivable - Loans by Risk Categories (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Gross	$ 1,555,904	$ 1,458,094
Pass [Member]
Financing Receivable, Gross	1,502,512	1,405,499
Special Mention [Member]
Financing Receivable, Gross	521	2,807
Substandard [Member]
Financing Receivable, Gross	52,871	49,788
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member]
Financing Receivable, Gross	389,107	401,036
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Pass [Member]
Financing Receivable, Gross	375,287	384,193
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Special Mention [Member]
Financing Receivable, Gross	206	1,098
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Substandard [Member]
Financing Receivable, Gross	13,614	15,745
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member]
Financing Receivable, Gross	92,460	74,226
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Pass [Member]
Financing Receivable, Gross	92,460	74,063
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Special Mention [Member]
Financing Receivable, Gross	0	0
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Substandard [Member]
Financing Receivable, Gross	0	163
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Financing Receivable, Gross	495,173	487,684
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Financing Receivable, Gross	473,343	462,552
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Financing Receivable, Gross	314	10
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Financing Receivable, Gross	21,516	25,122
Real Estate Portfolio Segment [Member] | Farmland [Member]
Financing Receivable, Gross	94,018	94,235
Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Financing Receivable, Gross	92,131	91,665
Real Estate Portfolio Segment [Member] | Farmland [Member] | Special Mention [Member]
Financing Receivable, Gross	0	1,095
Real Estate Portfolio Segment [Member] | Farmland [Member] | Substandard [Member]
Financing Receivable, Gross	1,887	1,475
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Gross	125,785	116,015
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Pass [Member]
Financing Receivable, Gross	116,269	114,534
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Special Mention [Member]
Financing Receivable, Gross	0	91
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Substandard [Member]
Financing Receivable, Gross	9,516	1,390
Commercial Portfolio Segment [Member]
Financing Receivable, Gross	323,096	246,304
Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Gross	317,069	240,209
Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Gross	0	501
Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable, Gross	6,027	5,594
Consumer Portfolio Segment [Member]
Financing Receivable, Gross	36,265	38,594
Consumer Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Gross	35,953	38,283
Consumer Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Gross	1	12
Consumer Portfolio Segment [Member] | Substandard [Member]
Financing Receivable, Gross	$ 311	$ 299