Note 6 - Allowance for Loan Losses and Impaired Loans - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Loans receivable	$ 570,353	$ 536,465
Construction and Development Loan [Member]
Loans receivable	39,649	33,449
Farmland Loan [Member]
Loans receivable	34,166	33,291
Residential Loan [Member]
Loans receivable	253,674	235,689
Commercial Mortgage Loan [Member]
Loans receivable	190,817	176,192
Commercial and Agricultural Loan [Member]
Loans receivable	32,426	37,491
Consumer and Other Loan [Member]
Loans receivable	19,621	20,353
Pass [Member]
Loans receivable	499,700	468,848
Pass [Member] | Construction and Development Loan [Member]
Loans receivable	34,701	31,237
Pass [Member] | Farmland Loan [Member]
Loans receivable	22,969	23,250
Pass [Member] | Residential Loan [Member]
Loans receivable	231,629	213,670
Pass [Member] | Commercial Mortgage Loan [Member]
Loans receivable	163,584	148,179
Pass [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	27,503	33,537
Pass [Member] | Consumer and Other Loan [Member]
Loans receivable	19,314	18,975
Watch [Member]
Loans receivable	55,353	53,511
Watch [Member] | Construction and Development Loan [Member]
Loans receivable	4,801	2,044
Watch [Member] | Farmland Loan [Member]
Loans receivable	4,059	4,933
Watch [Member] | Residential Loan [Member]
Loans receivable	19,887	18,794
Watch [Member] | Commercial Mortgage Loan [Member]
Loans receivable	21,960	23,468
Watch [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	4,346	2,908
Watch [Member] | Consumer and Other Loan [Member]
Loans receivable	300	1,364
Special Mention [Member]
Loans receivable	1,882	2,478
Special Mention [Member] | Construction and Development Loan [Member]
Loans receivable		147
Special Mention [Member] | Farmland Loan [Member]
Loans receivable	673	750
Special Mention [Member] | Residential Loan [Member]
Loans receivable	176	299
Special Mention [Member] | Commercial Mortgage Loan [Member]
Loans receivable	930	1,212
Special Mention [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	103	70
Special Mention [Member] | Consumer and Other Loan [Member]
Loans receivable
Substandard [Member]
Loans receivable	13,418	11,628
Substandard [Member] | Construction and Development Loan [Member]
Loans receivable	147	21
Substandard [Member] | Farmland Loan [Member]
Loans receivable	6,465	4,358
Substandard [Member] | Residential Loan [Member]
Loans receivable	1,982	2,926
Substandard [Member] | Commercial Mortgage Loan [Member]
Loans receivable	4,343	3,333
Substandard [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	474	976
Substandard [Member] | Consumer and Other Loan [Member]
Loans receivable	$ 7	$ 14