Note 3 - Loans - Aging of Recorded Investment in Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Nonaccrual	$ 1,528	$ 1,991
Total past due and nonaccrual	3,945	3,915
Financial Asset, 30 to 59 Days Past Due [Member]
Past due	1,747	1,593
Financial Asset, 60 to 89 Days Past Due [Member]
Past due	670	331
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member]
Nonaccrual	50	53
Total past due and nonaccrual	67	92
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	14	39
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	3	0
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Nonaccrual	0	0
Total past due and nonaccrual	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member]
Nonaccrual	431	249
Total past due and nonaccrual	705	600
Commercial Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Nonaccrual	90	61
Total past due and nonaccrual	296	113
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Construction Loans [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Farmland Loans [Member]
Past due	274	244
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Nonfarm Nonresidential [Member]
Past due	206	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Construction Loans [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Farmland Loans [Member]
Past due	0	107
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Nonfarm Nonresidential [Member]
Past due	0	52
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Farmland Loans [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Nonfarm Nonresidential [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Multifamily Loans [Member]
Nonaccrual	0	0
Total past due and nonaccrual	0	0
Residential Portfolio Segment [Member] | One- to Four-family Residential Properties [Member]
Nonaccrual	817	1,628
Total past due and nonaccrual	2,482	3,064
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Multifamily Loans [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | One- to Four-family Residential Properties [Member]
Past due	1,162	1,299
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Multifamily Loans [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | One- to Four-family Residential Properties [Member]
Past due	503	137
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Multifamily Loans [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | One- to Four-family Residential Properties [Member]
Past due	0	0
Consumer Portfolio Segment [Member]
Nonaccrual	98	0
Total past due and nonaccrual	353	43
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	91	8
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	164	35
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Agriculture Portfolio Segment [Member]
Nonaccrual	42	0
Total past due and nonaccrual	42	3
Agriculture Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	3
Agriculture Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		0
Agriculture Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Other Portfolio Segment [Member]
Nonaccrual	0	0
Total past due and nonaccrual	0	0
Other Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Other Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Other Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	$ 0	$ 0