Note 4 - Allowance for Loan Losses and Impaired Loans - Analysis of Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Loans receivable	$ 686,117		$ 664,095
Loans and Leases Receivable, Gross, Total	686,117		664,095
Past due and still accruing		$ 0	0
Nonaccrual loans		2,059	4,803
Construction and Development Loan [Member]
Loans receivable	44,435		46,053
Loans and Leases Receivable, Gross, Total	44,435		46,053
Past due and still accruing		0	0
Nonaccrual loans		426	11
Farmland Loan [Member]
Loans receivable	28,082		32,449
Loans and Leases Receivable, Gross, Total	28,082		32,449
Past due and still accruing		0	0
Nonaccrual loans		736	3,937
Residential Loan [Member]
Loans receivable	292,670		279,893
Loans and Leases Receivable, Gross, Total	292,670		279,893
Past due and still accruing		0	0
Nonaccrual loans		663	557
Commercial Mortgage Loan [Member]
Loans receivable	229,118		203,886
Loans and Leases Receivable, Gross, Total	229,118		203,886
Past due and still accruing		0	0
Nonaccrual loans		124	109
Commercial and Agricultural Loan [Member]
Loans receivable	32,726		33,663
Loans and Leases Receivable, Gross, Total	32,726		33,663
Past due and still accruing		0	0
Nonaccrual loans		110	189
SBA PPP Loans [Member]
Loans receivable	37,762		51,118
Loans and Leases Receivable, Gross, Total	37,762		51,118
Past due and still accruing		0	0
Nonaccrual loans		0	0
Consumer and Other Loan [Member]
Loans receivable	21,324		17,033
Loans and Leases Receivable, Gross, Total	21,324		17,033
Past due and still accruing		0	0
Nonaccrual loans		$ 0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable	506		578
Loans and Leases Receivable, Gross, Total	506		578
Financial Asset, 30 to 59 Days Past Due [Member] | Construction and Development Loan [Member]
Loans receivable	0		71
Loans and Leases Receivable, Gross, Total	0		71
Financial Asset, 30 to 59 Days Past Due [Member] | Farmland Loan [Member]
Loans receivable	0		100
Loans and Leases Receivable, Gross, Total	0		100
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Loan [Member]
Loans receivable	495		386
Loans and Leases Receivable, Gross, Total	495		386
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Mortgage Loan [Member]
Loans receivable	10		0
Loans and Leases Receivable, Gross, Total	10		0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	0		14
Loans and Leases Receivable, Gross, Total	0		14
Financial Asset, 30 to 59 Days Past Due [Member] | SBA PPP Loans [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer and Other Loan [Member]
Loans receivable	1		7
Loans and Leases Receivable, Gross, Total	1		7
Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable	50		44
Loans and Leases Receivable, Gross, Total	50		44
Financial Asset, 60 to 89 Days Past Due [Member] | Construction and Development Loan [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, 60 to 89 Days Past Due [Member] | Farmland Loan [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Loan [Member]
Loans receivable	40		29
Loans and Leases Receivable, Gross, Total	40		29
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Mortgage Loan [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	1		15
Loans and Leases Receivable, Gross, Total	1		15
Financial Asset, 60 to 89 Days Past Due [Member] | SBA PPP Loans [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer and Other Loan [Member]
Loans receivable	9		0
Loans and Leases Receivable, Gross, Total	9		0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable	974		1,333
Loans and Leases Receivable, Gross, Total	974		1,333
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction and Development Loan [Member]
Loans receivable	426		0
Loans and Leases Receivable, Gross, Total	426		0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Farmland Loan [Member]
Loans receivable	127		914
Loans and Leases Receivable, Gross, Total	127		914
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Loan [Member]
Loans receivable	279		240
Loans and Leases Receivable, Gross, Total	279		240
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Mortgage Loan [Member]
Loans receivable	46		24
Loans and Leases Receivable, Gross, Total	46		24
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	96		155
Loans and Leases Receivable, Gross, Total	96		155
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | SBA PPP Loans [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer and Other Loan [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, Past Due [Member]
Loans receivable	1,530		1,955
Loans and Leases Receivable, Gross, Total	1,530		1,955
Financial Asset, Past Due [Member] | Construction and Development Loan [Member]
Loans receivable	426		71
Loans and Leases Receivable, Gross, Total	426		71
Financial Asset, Past Due [Member] | Farmland Loan [Member]
Loans receivable	127		1,014
Loans and Leases Receivable, Gross, Total	127		1,014
Financial Asset, Past Due [Member] | Residential Loan [Member]
Loans receivable	814		655
Loans and Leases Receivable, Gross, Total	814		655
Financial Asset, Past Due [Member] | Commercial Mortgage Loan [Member]
Loans receivable	56		24
Loans and Leases Receivable, Gross, Total	56		24
Financial Asset, Past Due [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	97		184
Loans and Leases Receivable, Gross, Total	97		184
Financial Asset, Past Due [Member] | SBA PPP Loans [Member]
Loans receivable	0		0
Loans and Leases Receivable, Gross, Total	0		0
Financial Asset, Past Due [Member] | Consumer and Other Loan [Member]
Loans receivable	10		7
Loans and Leases Receivable, Gross, Total	10		7
Financial Asset, Not Past Due [Member]
Loans receivable	684,587		662,140
Loans and Leases Receivable, Gross, Total	684,587		662,140
Financial Asset, Not Past Due [Member] | Construction and Development Loan [Member]
Loans receivable	44,009		45,982
Loans and Leases Receivable, Gross, Total	44,009		45,982
Financial Asset, Not Past Due [Member] | Farmland Loan [Member]
Loans receivable	27,955		31,435
Loans and Leases Receivable, Gross, Total	27,955		31,435
Financial Asset, Not Past Due [Member] | Residential Loan [Member]
Loans receivable	291,856		279,238
Loans and Leases Receivable, Gross, Total	291,856		279,238
Financial Asset, Not Past Due [Member] | Commercial Mortgage Loan [Member]
Loans receivable	229,062		203,862
Loans and Leases Receivable, Gross, Total	229,062		203,862
Financial Asset, Not Past Due [Member] | Commercial and Agricultural Loan [Member]
Loans receivable	32,629		33,479
Loans and Leases Receivable, Gross, Total	32,629		33,479
Financial Asset, Not Past Due [Member] | SBA PPP Loans [Member]
Loans receivable	37,762		51,118
Loans and Leases Receivable, Gross, Total	37,762		51,118
Financial Asset, Not Past Due [Member] | Consumer and Other Loan [Member]
Loans receivable	21,314		17,026
Loans and Leases Receivable, Gross, Total	$ 21,314		$ 17,026