Note 3 - Loans Receivable - Components of Loans (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loans receivable	$ 697,379		$ 664,095
Allowance for loan losses	(5,342)	$ (5,051)	(4,900)	$ (4,654)	$ (4,252)	$ (3,893)
Loans, net of allowance for loan losses	692,037		659,195
Loans and Leases Receivable, Gross, Total	697,379		664,095
Loans receivable, gross	697,379		664,095
Construction and Development Loan [Member]
Loans receivable	40,954		46,053
Allowance for loan losses	(428)	(502)	(499)	(415)	(341)	(305)
Loans and Leases Receivable, Gross, Total	40,954		46,053
Loans receivable, gross	40,954		46,053
SBA PPP Loans [Member]
Loans receivable	$ 61,454		$ 51,118
Number of SBA Loans	2,008		1,008
Financing receivables, percent mix one	100.00%		100.00%
Loans and Leases Receivable, Gross, Total	$ 61,454		$ 51,118
Financing receivables, percent mix two	100.00%		100.00%
Number of industry SBA loans	2,008		1,008
Industry percentage mix one of SBA loans	100.00%		100.00%
Loans receivable, gross	$ 61,454		$ 51,118
Industry percentage mix two of SBA loans	100.00%		100.00%
SBA PPP Loans [Member] | Manufacturing [Member]
Loans receivable	$ 7,674		$ 14,327
Number of SBA Loans	72		74
Financing receivables, percent mix one	3.59%		7.34%
Loans and Leases Receivable, Gross, Total	$ 7,674		$ 14,327
Financing receivables, percent mix two	12.49%		28.03%
Number of industry SBA loans	72		74
Industry percentage mix one of SBA loans	3.59%		7.34%
Loans receivable, gross	$ 7,674		$ 14,327
Industry percentage mix two of SBA loans	12.49%		28.03%
SBA PPP Loans [Member] | Retail Trade [Member]
Loans receivable	$ 3,531		$ 5,247
Number of SBA Loans	154		134
Financing receivables, percent mix one	7.67%		13.29%
Loans and Leases Receivable, Gross, Total	$ 3,531		$ 5,247
Financing receivables, percent mix two	5.75%		10.26%
Number of industry SBA loans	154		134
Industry percentage mix one of SBA loans	7.67%		13.29%
Loans receivable, gross	$ 3,531		$ 5,247
Industry percentage mix two of SBA loans	5.75%		10.26%
SBA PPP Loans [Member] | Construction Industry [Member]
Loans receivable	$ 6,012		$ 3,577
Number of SBA Loans	242		127
Financing receivables, percent mix one	12.05%		12.60%
Loans and Leases Receivable, Gross, Total	$ 6,012		$ 3,577
Financing receivables, percent mix two	9.78%		7.00%
Number of industry SBA loans	242		127
Industry percentage mix one of SBA loans	12.05%		12.60%
Loans receivable, gross	$ 6,012		$ 3,577
Industry percentage mix two of SBA loans	9.78%		7.00%
SBA PPP Loans [Member] | Healthcare Sector [Member]
Loans receivable	$ 4,376		$ 3,550
Number of SBA Loans	72		73
Financing receivables, percent mix one	3.59%		7.24%
Loans and Leases Receivable, Gross, Total	$ 4,376		$ 3,550
Financing receivables, percent mix two	7.12%		6.94%
Number of industry SBA loans	72		73
Industry percentage mix one of SBA loans	3.59%		7.24%
Loans receivable, gross	$ 4,376		$ 3,550
Industry percentage mix two of SBA loans	7.12%		6.94%
SBA PPP Loans [Member] | Accommodation and Retail Services [Member]
Loans receivable	$ 8,183		$ 3,705
Number of SBA Loans	126		91
Financing receivables, percent mix one	6.27%		9.03%
Loans and Leases Receivable, Gross, Total	$ 8,183		$ 3,705
Financing receivables, percent mix two	13.31%		7.25%
Number of industry SBA loans	126		91
Industry percentage mix one of SBA loans	6.27%		9.03%
Loans receivable, gross	$ 8,183		$ 3,705
Industry percentage mix two of SBA loans	13.31%		7.25%
SBA PPP Loans [Member] | Education Services [Member]
Loans receivable	$ 6,236		$ 4,825
Number of SBA Loans	13		7
Financing receivables, percent mix one	0.65%		0.70%
Loans and Leases Receivable, Gross, Total	$ 6,236		$ 4,825
Financing receivables, percent mix two	10.15%		9.44%
Number of industry SBA loans	13		7
Industry percentage mix one of SBA loans	0.65%		0.70%
Loans receivable, gross	$ 6,236		$ 4,825
Industry percentage mix two of SBA loans	10.15%		9.44%
SBA PPP Loans [Member] | General and Other [Member]
Loans receivable	$ 25,442		$ 15,887
Number of SBA Loans	1,329		502
Financing receivables, percent mix one	66.18%		49.80%
Loans and Leases Receivable, Gross, Total	$ 25,442		$ 15,887
Financing receivables, percent mix two	41.40%		31.08%
Number of industry SBA loans	1,329		502
Industry percentage mix one of SBA loans	66.18%		49.80%
Loans receivable, gross	$ 25,442		$ 15,887
Industry percentage mix two of SBA loans	41.40%		31.08%
SBA PPP Loans [Member] | SBA Tier 1 [Member]
Loans receivable	$ 5,620		$ 7,267
Number of SBA Loans	2		2
Financing receivables, percent mix one	0.10%		0.20%
Loans and Leases Receivable, Gross, Total	$ 5,620		$ 7,267
Financing receivables, percent mix two	9.14%		14.22%
Number of industry SBA loans	2		2
Industry percentage mix one of SBA loans	0.10%		0.20%
Loans receivable, gross	$ 5,620		$ 7,267
Industry percentage mix two of SBA loans	9.14%		14.22%
SBA PPP Loans [Member] | SBA Tier 2 [Member]
Loans receivable	$ 12,935		$ 11,693
Number of SBA Loans	25		18
Financing receivables, percent mix one	1.24%		1.78%
Loans and Leases Receivable, Gross, Total	$ 12,935		$ 11,693
Financing receivables, percent mix two	21.05%		22.87%
Number of industry SBA loans	25		18
Industry percentage mix one of SBA loans	1.24%		1.78%
Loans receivable, gross	$ 12,935		$ 11,693
Industry percentage mix two of SBA loans	21.05%		22.87%
SBA PPP Loans [Member] | SBA Tier 3 [Member]
Loans receivable	$ 42,899		$ 32,158
Number of SBA Loans	1,981		988
Financing receivables, percent mix one	98.66%		98.02%
Loans and Leases Receivable, Gross, Total	$ 42,899		$ 32,158
Financing receivables, percent mix two	69.81%		62.91%
Number of industry SBA loans	1,981		988
Industry percentage mix one of SBA loans	98.66%		98.02%
Loans receivable, gross	$ 42,899		$ 32,158
Industry percentage mix two of SBA loans	69.81%		62.91%
Farmland Loan [Member]
Loans receivable	$ 30,447		$ 32,449
Allowance for loan losses	(344)	(384)	(406)	(472)	(465)	(487)
Loans and Leases Receivable, Gross, Total	30,447		32,449
Loans receivable, gross	30,447		32,449
Residential Loan [Member]
Loans receivable	287,643		279,893
Allowance for loan losses	(2,320)	(2,247)	(2,167)	(2,126)	(1,998)	(1,822)
Loans and Leases Receivable, Gross, Total	287,643		279,893
Loans receivable, gross	287,643		279,893
Commercial Mortgage Loan [Member]
Loans receivable	228,288		203,886
Allowance for loan losses	(1,843)	(1,557)	(1,421)	(1,051)	(1,054)	(924)
Loans and Leases Receivable, Gross, Total	228,288		203,886
Loans receivable, gross	228,288		203,886
Commercial and Agricultural Loan [Member]
Loans receivable	31,962		33,663
Allowance for loan losses	(273)	(259)	(293)	(450)	(246)	(211)
Loans and Leases Receivable, Gross, Total	31,962		33,663
Loans receivable, gross	31,962		33,663
Consumer and Other Loan [Member]
Loans receivable	16,631		17,033
Allowance for loan losses	(134)	$ (102)	(114)	$ (140)	$ (148)	$ (144)
Loans and Leases Receivable, Gross, Total	16,631		17,033
Loans receivable, gross	$ 16,631		$ 17,033