Note 3 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Individually evaluated for impairment					$ 138	$ 16
Collectively evaluated for impairment					6,242	5,033
Allowance for loan losses	$ 6,064	$ 4,739	$ 5,061	$ 4,065	6,404	5,061
Beginning balance	6,064	4,609	5,061	4,065
Provisions for loan losses	400	225	1,576	975
Charge-offs	(112)	(160)	(448)	(593)
Recoveries	52	65	215	292
Ending balance	6,404	4,739	6,404	4,739
Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	24		12		24	12
Beginning balance			12
Ending balance	24		24
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Individually evaluated for impairment					0	16
Collectively evaluated for impairment					1,105	839
Allowance for loan losses	1,055	806	867	693	1,129	867
Beginning balance	1,055	754	867	693
Provisions for loan losses	70	56	284	131
Charge-offs	0	(4)	(72)	(135)
Recoveries	4	0	50	117
Ending balance	1,129	806	1,129	806
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	24		12		24	12
Beginning balance			12
Ending balance	24		24
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					207	163
Allowance for loan losses	196	172	163	162	207	163
Beginning balance	196	170	163	162
Provisions for loan losses	11	1	44	9
Charge-offs	0	0	0	0
Recoveries	0	1	0	1
Ending balance	207	172	207	172
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					373	350
Allowance for loan losses	369	351	350	224	373	350
Beginning balance	369	316	350	224
Provisions for loan losses	4	35	23	127
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	373	351	373	351
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					2,054	1,623
Allowance for loan losses	1,902	1,482	1,623	1,401	2,054	1,623
Beginning balance	1,902	1,452	1,623	1,401
Provisions for loan losses	152	30	431	81
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	2,054	1,482	2,054	1,482
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Commercial Portfolio Segment [Member]
Individually evaluated for impairment					138	0
Collectively evaluated for impairment					715	595
Allowance for loan losses	868	552	595	459	853	595
Beginning balance	868	596	595	459
Provisions for loan losses	17	(48)	290	89
Charge-offs	(32)	0	(32)	0
Recoveries	0	4	0	4
Ending balance	853	552	853	552
Commercial Portfolio Segment [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					643	515
Allowance for loan losses	604	487	515	443	643	515
Beginning balance	604	472	515	443
Provisions for loan losses	39	14	117	39
Charge-offs	0	0	0	(2)
Recoveries	0	1	11	7
Ending balance	643	487	643	487
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					1,145	948
Allowance for loan losses	1,145		948		1,145	948
Beginning balance			948
Ending balance	1,145		1,145
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Allowance for loan losses	0		0		0	0
Beginning balance			0
Ending balance	0		0
Consumer Portfolio Segment [Member] \| Other Consumer Loan [Member]
Allowance for loan losses	1,145	889	948	683	$ 1,145	$ 948
Beginning balance	1,070	849	948	683
Provisions for loan losses	107	137	387	499
Charge-offs	(80)	(156)	(344)	(456)
Recoveries	48	59	154	163
Ending balance	$ 1,145	$ 889	$ 1,145	$ 889

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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