Note 4 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Average recorded investment	$ 10,153	$ 17,915
Interest income recognized	50	75
Commercial Portfolio Segment [Member]
Average recorded investment	640	2,021
Interest income recognized	9	17
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment		8,412
Interest income recognized		11
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	3,103
Interest income recognized
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	5,957	6,874
Interest income recognized	37	42
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	186	184
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	228	401
Interest income recognized	4	5
Consumer Portfolio Segment [Member]
Average recorded investment	39	23
Interest income recognized