Note 4 - Loans Receivable - Loans by Risk Categories (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans receivable, gross	$ 1,710,820	$ 1,555,904
Pass [Member]
Loans receivable, gross	1,669,742	1,502,512
Special Mention [Member]
Loans receivable, gross	448	521
Substandard [Member]
Loans receivable, gross	40,630	52,871
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member]
Loans receivable, gross	393,082	389,107
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Pass [Member]
Loans receivable, gross	381,310	375,287
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Special Mention [Member]
Loans receivable, gross	153	206
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member] | Substandard [Member]
Loans receivable, gross	11,619	13,614
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member]
Loans receivable, gross	92,837	92,460
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Pass [Member]
Loans receivable, gross	92,837	92,460
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Special Mention [Member]
Loans receivable, gross	0	0
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Substandard [Member]
Loans receivable, gross
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Loans receivable, gross	568,318	495,173
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Pass [Member]
Loans receivable, gross	553,832	473,343
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Special Mention [Member]
Loans receivable, gross	295	314
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Substandard [Member]
Loans receivable, gross	14,191	21,516
Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans receivable, gross	99,189	94,018
Real Estate Portfolio Segment [Member] | Farmland [Member] | Pass [Member]
Loans receivable, gross	96,981	92,131
Real Estate Portfolio Segment [Member] | Farmland [Member] | Special Mention [Member]
Loans receivable, gross	0
Real Estate Portfolio Segment [Member] | Farmland [Member] | Substandard [Member]
Loans receivable, gross	2,208	1,887
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable, gross	147,071	125,785
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Pass [Member]
Loans receivable, gross	138,483	116,269
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Special Mention [Member]
Loans receivable, gross	0
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Substandard [Member]
Loans receivable, gross	8,588	9,516
Commercial Portfolio Segment [Member]
Loans receivable, gross	373,464	323,096
Commercial Portfolio Segment [Member] | Pass [Member]
Loans receivable, gross	369,750	317,069
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans receivable, gross
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans receivable, gross	3,714	6,027
Consumer Portfolio Segment [Member]
Loans receivable, gross	36,859	36,265
Consumer Portfolio Segment [Member] | Pass [Member]
Loans receivable, gross	36,549	35,953
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans receivable, gross		1
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans receivable, gross	$ 310	$ 311