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, 2020	Mar. 31, 2019	Dec. 31, 2019
Balance	$ 6,863	$ 7,390	$ 7,390
Charge-offs	(175)	(328)	(920)
Recoveries	73	98	267
Provision for loan losses	479	200	126
Balance	7,240	7,360	6,863
Real Estate Construction Portfolio Segment[Member]
Balance	400	398	398
Charge-offs	0
Recoveries	0	0	0
Provision for loan losses	(25)	70	2
Balance	375	468	400
Consumer Real Estate Portfolio Segment [Member]
Balance	1,895	2,049	2,049
Charge-offs	(44)	(16)	(192)
Recoveries
Provision for loan losses	219	58	38
Balance	2,070	2,091	1,895
Commercial Real Estate Portfolio Segment [Member]
Balance	2,559	2,798	2,798
Charge-offs		(150)	(150)
Recoveries	12	12	49
Provision for loan losses	29	327	(138)
Balance	2,600	2,987	2,559
Commercial Non Real Estate Segment [Member]
Balance	555	602	602
Charge-offs	(65)		(47)
Recoveries	1		1
Provision for loan losses	230	(27)	(1)
Balance	721	575	555
Public Sector and IDA Portfolio Segment[Member]
Balance	478	583	583
Charge-offs	0	0	0
Recoveries	0	0	0
Provision for loan losses	33	(58)	(105)
Balance	511	525	478
Consumer Non Real Estate Portfolio Segment [Member]
Balance	650	750	750
Charge-offs	(66)	(162)	(531)
Recoveries	60	86	217
Provision for loan losses	(25)		214
Balance	619	674	650
Unallocated Financing Receivables [Member]
Balance	326	210	210
Charge-offs	0	0	0
Recoveries	0	0	0
Provision for loan losses	18	(170)	116
Balance	$ 344	$ 40	$ 326