Note 4 - Allowance for Loan Losses and Impaired Loans - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Loans receivable	$ 686,117	$ 664,095
Construction and Development Loan [Member]
Loans receivable	44,435	46,053
Farmland Loan [Member]
Loans receivable	28,082	32,449
Residential Loan [Member]
Loans receivable	292,670	279,893
Commercial Mortgage Loan [Member]
Loans receivable	229,118	203,886
Commercial and Agricultural Loan [Member]
Loans receivable	32,726	33,663
SBA PPP Loans [Member]
Loans receivable	37,762	51,118
Consumer and Other Loan [Member]
Loans receivable	21,324	17,033
Pass [Member]
Loans receivable	663,015	637,096
Pass [Member] | Construction and Development Loan [Member]
Loans receivable	43,583	44,909
Pass [Member] | Farmland Loan [Member]
Loans receivable	22,275	25,607
Pass [Member] | Residential Loan [Member]
Loans receivable	290,317	277,811
Pass [Member] | Commercial Mortgage Loan [Member]
Loans receivable	215,413	188,156
Pass [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	32,341	32,467
Pass [Member] | SBA PPP Loans [Member]
Loans receivable	37,762	51,118
Pass [Member] | Consumer and Other Loan [Member]
Loans receivable	21,324	17,028
Watch [Member]
Loans receivable	6,265	10,665
Watch [Member] | Construction and Development Loan [Member]
Loans receivable	0	427
Watch [Member] | Farmland Loan [Member]
Loans receivable	840	419
Watch [Member] | Residential Loan [Member]
Loans receivable	358	659
Watch [Member] | Commercial Mortgage Loan [Member]
Loans receivable	5,067	8,692
Watch [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	0	468
Watch [Member] | SBA PPP Loans [Member]
Loans receivable	0	0
Watch [Member] | Consumer and Other Loan [Member]
Loans receivable	0	0
Special Mention [Member]
Loans receivable	6,607	4,426
Special Mention [Member] | Construction and Development Loan [Member]
Loans receivable	0	122
Special Mention [Member] | Farmland Loan [Member]
Loans receivable	484	496
Special Mention [Member] | Residential Loan [Member]
Loans receivable	604	0
Special Mention [Member] | Commercial Mortgage Loan [Member]
Loans receivable	5,474	3,647
Special Mention [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	45	161
Special Mention [Member] | SBA PPP Loans [Member]
Loans receivable	0	0
Special Mention [Member] | Consumer and Other Loan [Member]
Loans receivable	0	0
Substandard [Member]
Loans receivable	10,230	11,908
Substandard [Member] | Construction and Development Loan [Member]
Loans receivable	852	595
Substandard [Member] | Farmland Loan [Member]
Loans receivable	4,483	5,927
Substandard [Member] | Residential Loan [Member]
Loans receivable	1,391	1,423
Substandard [Member] | Commercial Mortgage Loan [Member]
Loans receivable	3,164	3,391
Substandard [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	340	567
Substandard [Member] | SBA PPP Loans [Member]
Loans receivable	0	0
Substandard [Member] | Consumer and Other Loan [Member]
Loans receivable	$ 0	$ 5