Note 5 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Average recorded investment	$ 17,940	$ 11,207
Interest income recognized	260	314
Commercial Portfolio Segment [Member]
Average recorded investment	1,201	2,455
Interest income recognized	51	78
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	9,400	890
Interest income recognized	30	46
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	259
Interest income recognized
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	6,574	7,198
Interest income recognized	161	170
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	193	218
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	288	415
Interest income recognized	18	20
Consumer Portfolio Segment [Member]
Average recorded investment	25	31
Interest income recognized