Note 5 - Allowances for Loan Losses - Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Beginning balance				$ 9,266				$ 8,615	$ 9,266	$ 8,615	$ 8,599
Charge-offs									(555)	(1,482)	(2,438)
Recoveries									64	228	154
Provision for loan losses	$ 1,400	$ 850	$ 1,000	950	$ 1,155	$ 450	$ 0	300	4,200	1,905	2,300
Ending balance	12,975				9,266				12,975	9,266	8,615
Allowance for loan losses, individually evaluated for impairment												$ 591	$ 556
Allowance for loan losses, collectively evaluated for impairment												12,384	8,710
Total allowance for loan losses	12,975			9,266	9,266			8,615	12,975	8,615	8,599	12,975	9,266
Loans evaluated individually												17,969	18,882
Loans evaluated collectively												2,640,173	1,729,214
Total loans receivable												2,658,142	1,748,096
Commercial Real Estate Portfolio Segment [Member]
Beginning balance				3,043				2,462	3,043	2,462	3,774
Charge-offs									0	0	(1,603)
Recoveries									0	0	50
Provision for loan losses									1,351	581	241
Ending balance	4,394				3,043				4,394	3,043	2,462
Allowance for loan losses, individually evaluated for impairment												418	265
Allowance for loan losses, collectively evaluated for impairment												3,976	2,778
Total allowance for loan losses	4,394			3,043	3,043			2,462	4,394	2,462	3,774	4,394	3,043
Loans evaluated individually												9,048	10,331
Loans evaluated collectively												696,700	603,300
Total loans receivable												705,748	613,631
Construction and Land Development Portfolio Segment [Member]
Beginning balance				688				777	688	777	725
Charge-offs									0	0	0
Recoveries									3	0	0
Provision for loan losses									257	(89)	52
Ending balance	948				688				948	688	777
Allowance for loan losses, individually evaluated for impairment												0	0
Allowance for loan losses, collectively evaluated for impairment												948	688
Total allowance for loan losses	948			688	688			777	948	777	725	948	688
Loans evaluated individually													0
Loans evaluated collectively												142,821	121,395
Total loans receivable												142,821	121,395
Commercial Portfolio Segment [Member]
Beginning balance				931				1,754	931	1,754	1,317
Charge-offs									(333)	(1,356)	(151)
Recoveries									48	217	81
Provision for loan losses									721	316	507
Ending balance	1,367				931				1,367	931	1,754
Allowance for loan losses, individually evaluated for impairment												51	23
Allowance for loan losses, collectively evaluated for impairment												1,316	908
Total allowance for loan losses	1,367			931	931			1,754	1,367	1,754	1,317	1,367	931
Loans evaluated individually												2,963	3,087
Loans evaluated collectively												197,225	220,819
Total loans receivable												200,188	223,906
Owner Occupied Real Estate [Member]
Beginning balance				2,292				2,033	2,292	2,033	1,737
Charge-offs									(48)	0	(465)
Recoveries									1	2	20
Provision for loan losses									129	257	741
Ending balance	2,374				2,292				2,374	2,292	2,033
Allowance for loan losses, individually evaluated for impairment												122	268
Allowance for loan losses, collectively evaluated for impairment												2,252	2,024
Total allowance for loan losses	2,374			2,292	2,292			2,033	2,374	2,033	1,737	2,374	2,292
Loans evaluated individually												3,955	3,634
Loans evaluated collectively												471,251	420,766
Total loans receivable												475,206	424,400
Consumer Portfolio Segment [Member]
Beginning balance				590				577	590	577	573
Charge-offs									(107)	(126)	(219)
Recoveries									12	9	3
Provision for loan losses									228	130	220
Ending balance	723				590				723	590	577
Allowance for loan losses, individually evaluated for impairment												0	0
Allowance for loan losses, collectively evaluated for impairment												723	590
Total allowance for loan losses	723			590	590			577	723	577	573	723	590
Loans evaluated individually												1,302	1,062
Loans evaluated collectively												101,066	100,258
Total loans receivable												102,368	101,320
Residential Portfolio Segment [Member]
Beginning balance				1,705				894	1,705	894	392
Charge-offs									(67)	0	0
Recoveries									0	0	0
Provision for loan losses									1,387	811	502
Ending balance	3,025				1,705				3,025	1,705	894
Allowance for loan losses, individually evaluated for impairment												0	0
Allowance for loan losses, collectively evaluated for impairment												3,025	1,705
Total allowance for loan losses	3,025			1,705	1,705			894	3,025	894	392	3,025	1,705
Loans evaluated individually												701	768
Loans evaluated collectively												394,473	262,676
Total loans receivable												395,174	263,444
Paycheck Protection Program CARES Act [Member]
Beginning balance				0				0	0	0	0
Charge-offs									0	0	0
Recoveries									0	0	0
Provision for loan losses									0	0	0
Ending balance	0				0				0	0	0
Allowance for loan losses, individually evaluated for impairment												0	0
Allowance for loan losses, collectively evaluated for impairment												0	0
Total allowance for loan losses	0			0	0			0	0	0	0	0	0
Loans evaluated individually												0	0
Loans evaluated collectively												636,637	0
Total loans receivable												636,637	0
Unallocated Financing Receivables [Member]
Beginning balance				17				118	17	118	81
Charge-offs									0	0	0
Recoveries									0	0	0
Provision for loan losses									127	(101)	37
Ending balance	144				17				144	17	118
Allowance for loan losses, individually evaluated for impairment												0	0
Allowance for loan losses, collectively evaluated for impairment												144	17
Total allowance for loan losses	$ 144			$ 17	$ 17			$ 118	$ 144	$ 118	$ 81	144	17
Loans evaluated individually												0	0
Loans evaluated collectively												0	0
Total loans receivable												$ 0	$ 0