Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans, collectively evaluated for impairment		$ 724,345		$ 728,738
Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment		40,483		42,303
Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		178,475		180,713
Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		358,577		361,765
Commercial Non Real Estate Segment [Member]
Loans, collectively evaluated for impairment		50,201		45,658
Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		34,313		$ 34,535
Pass [Member]
Loans, collectively evaluated for impairment	[1]	723,068	$ 727,642
Pass [Member] | States Political Subdivisions [Member]
Loans, collectively evaluated for impairment	[1]	62,296	63,764
Special Mention [Member]
Loans, collectively evaluated for impairment	[1]	153	135
Special Mention [Member] | States Political Subdivisions [Member]
Loans, collectively evaluated for impairment	[1]	0	0
Classified Excluding Impaired [Member]
Loans, collectively evaluated for impairment	[1]	1,124	961
Classified Excluding Impaired [Member] | States Political Subdivisions [Member]
Loans, collectively evaluated for impairment	[1]	0	0
Construction, 1-4 Family Residential [Member] | Pass [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]	7,610	7,590
Construction, 1-4 Family Residential [Member] | Special Mention [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]
Construction, 1-4 Family Residential [Member] | Classified Excluding Impaired [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]	0	0
Construction, Other [Member] | Pass [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]	32,852	34,713
Construction, Other [Member] | Special Mention [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]
Construction, Other [Member] | Classified Excluding Impaired [Member] | Real Estate Construction Portfolio Segment[Member]
Loans, collectively evaluated for impairment	[1]	21	0
Equity Lines [Member] | Pass [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	16,619	16,435
Equity Lines [Member] | Special Mention [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Equity Lines [Member] | Classified Excluding Impaired [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	37	0
Closed End First Liens [Member] | Pass [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		92,190	94,814
Closed End First Liens [Member] | Special Mention [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment
Closed End First Liens [Member] | Classified Excluding Impaired [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		665	517
Closed End Junior Liens [Member] | Pass [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		3,711	3,861
Closed End Junior Liens [Member] | Special Mention [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment
Closed End Junior Liens [Member] | Classified Excluding Impaired [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment		83
Investor Owned Residential Real Estate [Member] | Pass [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	65,147	65,063
Investor Owned Residential Real Estate [Member] | Special Mention [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Investor Owned Residential Real Estate [Member] | Classified Excluding Impaired [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	23	23
Multifamily Real Estate [Member] | Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	83,688	87,934
Multifamily Real Estate [Member] | Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Multifamily Real Estate [Member] | Classified Excluding Impaired [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]		94
Commercial Real Estate, Owner Occupied [Member] | Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	130,191	127,937
Commercial Real Estate, Owner Occupied [Member] | Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	17
Commercial Real Estate, Owner Occupied [Member] | Classified Excluding Impaired [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	133	164
Commercial Real Estate Other [Member] | Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	144,548	145,636
Commercial Real Estate Other [Member] | Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Commercial Real Estate Other [Member] | Classified Excluding Impaired [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Commercial and Industrial [Member] | Pass [Member] | Commercial Non Real Estate Segment [Member]
Loans, collectively evaluated for impairment	[1]	49,932	45,387
Commercial and Industrial [Member] | Special Mention [Member] | Commercial Non Real Estate Segment [Member]
Loans, collectively evaluated for impairment	[1]	136	135
Commercial and Industrial [Member] | Classified Excluding Impaired [Member] | Commercial Non Real Estate Segment [Member]
Loans, collectively evaluated for impairment	[1]	133	136
Credit Card Receivable [Member] | Pass [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	5,231	5,703
Credit Card Receivable [Member] | Special Mention [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	0	0
Credit Card Receivable [Member] | Classified Excluding Impaired [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	0	0
Automobile Loan [Member] | Pass [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	13,994	14,810
Automobile Loan [Member] | Special Mention [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Automobile Loan [Member] | Classified Excluding Impaired [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	24	19
Other Consumer Loans [Member] | Pass [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	15,059	13,995
Other Consumer Loans [Member] | Special Mention [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]
Other Consumer Loans [Member] | Classified Excluding Impaired [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, collectively evaluated for impairment	[1]	$ 5	$ 8

[1] Excludes impaired, if any.