Note 4 - Loans, Allowance for Loan Losses/Credit Losses and Other Real Estate Owned (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans and Leases Receivable, Allowance, Ending Balance	$ 24,804	$ 20,477	$ 19,484	$ 21,351
Loans and Leases Receivable, Nonaccrual, Commitment to Lend	0		0
Financing Receivable, Troubled Debt Restructuring	$ 6,362		6,713
Troubled Debt Restructurings During Period	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0	$ 0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0	0
Financing Receivable, Held-for-Sale	$ 0		0
Other Real Estate, Ending Balance	43		43
Other Real Estate, Reserve	0		0
Mortgage Loans in Process of Foreclosure, Amount	393		124
Residential Real Estate Included in OREO [Member]
Real Estate Acquired Through Foreclosure	0		0
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Allowance, Ending Balance	4,753	$ 3,927	4,064	3,884
Financing Receivable, Troubled Debt Restructuring	6,156		6,492
Pledged Financial Instruments, Not Separately Reported, Loans Receivable Pledged as Collateral, Total	$ 0
Number of Collateral-dependent Loans	1
Collateral-dependent Loans, Balance	$ 3,240
Consumer Portfolio Segment [Member]
Loans and Leases Receivable, Allowance, Ending Balance	11,538	5,481	6,445	5,645
Consumer Portfolio Segment [Member] | Financial Asset, 60 or More Days Past Due [Member]
Collateral-dependent Loans, Balance	1,060
Residential Portfolio Segment [Member]
Loans and Leases Receivable, Allowance, Ending Balance	70	$ 261	206	$ 869
Financing Receivable, Troubled Debt Restructuring	$ 188		189
Number of Collateral-dependent Loans	2
Collateral-dependent Loans, Balance	$ 393
Restructured Loans [Member]
Financing Receivable, Troubled Debt Restructuring	6,362		6,713
Impaired Loans, Restructured, Nonaccrual Status	3,420		$ 3,670
Nonperforming Financial Instruments [Member]
Loans and Leases Receivable, Allowance, Ending Balance	$ 0