Note 5 - Loans Receivable (Details) - USD ($)	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Real Estate Portfolio Segment [Member] | One-to-Four-Family Residential [Member]
Loans receivable, gross	$ 390,066,000		$ 401,036,000
Allowance for loan and lease losses	(3,892,000)	$ (3,795,000)	(3,870,000)	$ (4,165,000)	$ (4,219,000)	$ (4,488,000)
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member]
Loans receivable, gross	80,334,000		74,226,000
Allowance for loan and lease losses	(779,000)	(787,000)	(665,000)	(581,000)	(633,000)	(791,000)
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Loans receivable, gross	477,278,000		487,684,000
Allowance for loan and lease losses	(3,146,000)	(3,306,000)	(3,599,000)	(3,880,000)	(3,970,000)	(4,243,000)
Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans receivable, gross	92,452,000		94,235,000
Allowance for loan and lease losses	(716,000)	(665,000)	(714,000)	(518,000)	(487,000)	(342,000)
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans receivable, gross	124,369,000		116,015,000
Allowance for loan and lease losses	(1,569,000)	(1,571,000)	(1,456,000)	(1,121,000)	(1,070,000)	(1,023,000)
Commercial Portfolio Segment [Member]
Loans receivable, gross	281,874,000		246,304,000
Allowance for loan and lease losses	(3,603,000)	(3,145,000)	(2,565,000)	(1,765,000)	(1,659,000)	(2,315,000)
Consumer Portfolio Segment [Member]
Loans receivable, gross	36,339,000		38,594,000
Allowance for loan and lease losses	(174,000)	(176,000)	(166,000)	(121,000)	(107,000)	(101,000)
Loans receivable, gross	1,482,712,000		1,458,094,000
Unearned discounts and net deferred loan costs	677,000		558,000
Allowance for loan and lease losses	(14,751,000)	$ (14,866,000)	(14,550,000)	$ (13,854,000)	$ (13,762,000)	$ (13,660,000)
Loans receivable—net	$ 1,468,638,000		$ 1,444,102,000