Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Balance	$ 8,481	$ 6,863	$ 6,863
Charge-offs	(47)	(175)	(720)
Recoveries	52	73	347
Provision for loan losses	50	479	1,991
Balance	8,536	7,240	8,481
Real Estate Construction Portfolio Segment[Member]
Balance	503	400	400
Provision for loan losses	8	(25)	103
Balance	511	375	503
Consumer Real Estate Portfolio Segment [Member]
Balance	2,165	1,895	1,895
Charge-offs	0	(44)	(85)
Recoveries	0		18
Provision for loan losses	201	219	337
Balance	2,366	2,070	2,165
Commercial Real Estate Portfolio Segment [Member]
Balance	3,853	2,559	2,559
Charge-offs	0	0
Recoveries	12	12	145
Provision for loan losses	(3)	29	1,164
Balance	3,862	2,600	3,853
Commercial Non Real Estate Segment [Member]
Balance	670	555	555
Charge-offs	0	(65)	(372)
Recoveries	2	1	9
Provision for loan losses	(38)	230	478
Balance	634	721	670
Public Sector and IDA Portfolio Segment[Member]
Balance	339	478	478
Provision for loan losses	(28)	33	(139)
Balance	311	511	339
Consumer Non Real Estate Portfolio Segment [Member]
Balance	555	650	650
Charge-offs	(47)	(66)	(248)
Recoveries	38	60	175
Provision for loan losses	(50)	(25)	(22)
Balance	496	619	555
Unallocated Financing Receivables [Member]
Balance	396	326	326
Provision for loan losses	(40)	18	70
Balance	$ 356	$ 344	$ 396