Note 3 - Loans Receivable - Components of Loans (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loans receivable	$ 686,117		$ 664,095
Allowance for loan losses	(5,550)	$ (5,342)	(4,900)	$ (4,794)	$ (4,654)	$ (3,893)
Loans, net of allowance for loan losses	680,567		659,195
Loans and Leases Receivable, Gross, Total	686,117		664,095
Loans receivable, gross	686,117		664,095
Construction and Development Loan [Member]
Loans receivable	44,435		46,053
Allowance for loan losses	(488)	(428)	(499)	(407)	(415)	(305)
Loans and Leases Receivable, Gross, Total	44,435		46,053
Loans receivable, gross	44,435		46,053
SBA PPP Loans [Member]
Loans receivable	$ 37,762		$ 51,118
Number of SBA Loans	1,434		1,008
Financing receivables, percent mix one	100.00%		100.00%
Loans and Leases Receivable, Gross, Total	$ 37,762		$ 51,118
Financing receivables, percent mix two	100.00%		100.00%
Number of industry SBA loans	1,434		1,008
Industry percentage mix one of SBA loans	100.00%		100.00%
Loans receivable, gross	$ 37,762		$ 51,118
Industry percentage mix two of SBA loans	100.00%		100.00%
SBA PPP Loans [Member] | Manufacturing [Member]
Loans receivable	$ 3,929		$ 14,327
Number of SBA Loans	46		74
Financing receivables, percent mix one	3.21%		7.34%
Loans and Leases Receivable, Gross, Total	$ 3,929		$ 14,327
Financing receivables, percent mix two	10.41%		28.03%
Number of industry SBA loans	46		74
Industry percentage mix one of SBA loans	3.21%		7.34%
Loans receivable, gross	$ 3,929		$ 14,327
Industry percentage mix two of SBA loans	10.41%		28.03%
SBA PPP Loans [Member] | Retail Trade [Member]
Loans receivable	$ 1,848		$ 5,247
Number of SBA Loans	102		134
Financing receivables, percent mix one	7.11%		13.29%
Loans and Leases Receivable, Gross, Total	$ 1,848		$ 5,247
Financing receivables, percent mix two	4.89%		10.26%
Number of industry SBA loans	102		134
Industry percentage mix one of SBA loans	7.11%		13.29%
Loans receivable, gross	$ 1,848		$ 5,247
Industry percentage mix two of SBA loans	4.89%		10.26%
SBA PPP Loans [Member] | Construction Industry [Member]
Loans receivable	$ 3,980		$ 3,577
Number of SBA Loans	190		127
Financing receivables, percent mix one	13.25%		12.60%
Loans and Leases Receivable, Gross, Total	$ 3,980		$ 3,577
Financing receivables, percent mix two	10.54%		7.00%
Number of industry SBA loans	190		127
Industry percentage mix one of SBA loans	13.25%		12.60%
Loans receivable, gross	$ 3,980		$ 3,577
Industry percentage mix two of SBA loans	10.54%		7.00%
SBA PPP Loans [Member] | Healthcare Sector [Member]
Loans receivable	$ 2,543		$ 3,550
Number of SBA Loans	40		73
Financing receivables, percent mix one	2.79%		7.24%
Loans and Leases Receivable, Gross, Total	$ 2,543		$ 3,550
Financing receivables, percent mix two	6.73%		6.94%
Number of industry SBA loans	40		73
Industry percentage mix one of SBA loans	2.79%		7.24%
Loans receivable, gross	$ 2,543		$ 3,550
Industry percentage mix two of SBA loans	6.73%		6.94%
SBA PPP Loans [Member] | Accommodation and Retail Services [Member]
Loans receivable	$ 6,021		$ 3,705
Number of SBA Loans	90		91
Financing receivables, percent mix one	6.27%		9.03%
Loans and Leases Receivable, Gross, Total	$ 6,021		$ 3,705
Financing receivables, percent mix two	15.95%		7.25%
Number of industry SBA loans	90		91
Industry percentage mix one of SBA loans	6.27%		9.03%
Loans receivable, gross	$ 6,021		$ 3,705
Industry percentage mix two of SBA loans	15.95%		7.25%
SBA PPP Loans [Member] | Education Services [Member]
Loans receivable	$ 2,432		$ 4,825
Number of SBA Loans	9		7
Financing receivables, percent mix one	0.63%		0.70%
Loans and Leases Receivable, Gross, Total	$ 2,432		$ 4,825
Financing receivables, percent mix two	6.44%		9.44%
Number of industry SBA loans	9		7
Industry percentage mix one of SBA loans	0.63%		0.70%
Loans receivable, gross	$ 2,432		$ 4,825
Industry percentage mix two of SBA loans	6.44%		9.44%
SBA PPP Loans [Member] | General and Other [Member]
Loans receivable	$ 17,009		$ 15,887
Number of SBA Loans	957		502
Financing receivables, percent mix one	66.74%		49.80%
Loans and Leases Receivable, Gross, Total	$ 17,009		$ 15,887
Financing receivables, percent mix two	45.04%		31.08%
Number of industry SBA loans	957		502
Industry percentage mix one of SBA loans	66.74%		49.80%
Loans receivable, gross	$ 17,009		$ 15,887
Industry percentage mix two of SBA loans	45.04%		31.08%
SBA PPP Loans [Member] | SBA Tier 1 [Member]
Loans receivable	$ 1,947		$ 7,267
Number of SBA Loans	1		2
Financing receivables, percent mix one	0.07%		0.20%
Loans and Leases Receivable, Gross, Total	$ 1,947		$ 7,267
Financing receivables, percent mix two	5.16%		14.22%
Number of industry SBA loans	1		2
Industry percentage mix one of SBA loans	0.07%		0.20%
Loans receivable, gross	$ 1,947		$ 7,267
Industry percentage mix two of SBA loans	5.16%		14.22%
SBA PPP Loans [Member] | SBA Tier 2 [Member]
Loans receivable	$ 8,062		$ 11,693
Number of SBA Loans	18		18
Financing receivables, percent mix one	1.26%		1.78%
Loans and Leases Receivable, Gross, Total	$ 8,062		$ 11,693
Financing receivables, percent mix two	21.35%		22.87%
Number of industry SBA loans	18		18
Industry percentage mix one of SBA loans	1.26%		1.78%
Loans receivable, gross	$ 8,062		$ 11,693
Industry percentage mix two of SBA loans	21.35%		22.87%
SBA PPP Loans [Member] | SBA Tier 3 [Member]
Loans receivable	$ 27,753		$ 32,158
Number of SBA Loans	1,415		988
Financing receivables, percent mix one	98.67%		98.02%
Loans and Leases Receivable, Gross, Total	$ 27,753		$ 32,158
Financing receivables, percent mix two	73.49%		62.91%
Number of industry SBA loans	1,415		988
Industry percentage mix one of SBA loans	98.67%		98.02%
Loans receivable, gross	$ 27,753		$ 32,158
Industry percentage mix two of SBA loans	73.49%		62.91%
Farmland Loan [Member]
Loans receivable	$ 28,082		$ 32,449
Allowance for loan losses	(312)	(344)	(406)	(464)	(472)	(487)
Loans and Leases Receivable, Gross, Total	28,082		32,449
Loans receivable, gross	28,082		32,449
Residential Loan [Member]
Loans receivable	292,670		279,893
Allowance for loan losses	(2,437)	(2,320)	(2,167)	(2,167)	(2,126)	(1,822)
Loans and Leases Receivable, Gross, Total	292,670		279,893
Loans receivable, gross	292,670		279,893
Commercial Mortgage Loan [Member]
Loans receivable	229,118		203,886
Allowance for loan losses	(1,929)	(1,843)	(1,421)	(1,236)	(1,051)	(924)
Loans and Leases Receivable, Gross, Total	229,118		203,886
Loans receivable, gross	229,118		203,886
Commercial and Agricultural Loan [Member]
Loans receivable	32,726		33,663
Allowance for loan losses	(270)	(273)	(293)	(398)	(450)	(211)
Loans and Leases Receivable, Gross, Total	32,726		33,663
Loans receivable, gross	32,726		33,663
Consumer and Other Loan [Member]
Loans receivable	21,324		17,033
Allowance for loan losses	(114)	$ (134)	(114)	$ (122)	$ (140)	$ (144)
Loans and Leases Receivable, Gross, Total	21,324		17,033
Loans receivable, gross	$ 21,324		$ 17,033