Note 3 - Loans - Recorded Investment in Nonaccrual and Loans Past Due 90 Days and Still on Accrual by Class of Loan (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Nonaccrual	$ 1,500	$ 1,528
Loans Past Due 90 Days and Over Still Accruing	0	0
Commercial Portfolio Segment [Member]
Nonaccrual	158	50
Loans Past Due 90 Days and Over Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Nonaccrual	0	0
Loans Past Due 90 Days and Over Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member]
Nonaccrual	298	431
Loans Past Due 90 Days and Over Still Accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Nonaccrual	89	90
Loans Past Due 90 Days and Over Still Accruing	0	0
Residential Portfolio Segment [Member] | Multifamily Loans [Member]
Nonaccrual	0	0
Loans Past Due 90 Days and Over Still Accruing	0	0
Residential Portfolio Segment [Member] | One- to Four-family Residential Properties [Member]
Nonaccrual	812	817
Loans Past Due 90 Days and Over Still Accruing	0	0
Consumer Portfolio Segment [Member]
Nonaccrual	143	98
Loans Past Due 90 Days and Over Still Accruing	0	0
Agriculture Portfolio Segment [Member]
Nonaccrual		42
Loans Past Due 90 Days and Over Still Accruing	0	0
Other Portfolio Segment [Member]
Nonaccrual	0	0
Loans Past Due 90 Days and Over Still Accruing	$ 0	$ 0