Note 4 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Average recorded investment	$ 7,811	$ 10,486	$ 8,908	$ 10,319
Interest income recognized	41	47	82	96
Commercial Portfolio Segment [Member]
Average recorded investment	1,972	613	1,996	626
Interest income recognized	7	9	14	17
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	613	926	622	463
Interest income recognized	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	91	3,066	1,091	3,084
Interest income recognized	0	0	0	0
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	4,869	5,440	4,926	5,698
Interest income recognized	32	34	64	72
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	135	181	137	184
Interest income recognized	0	0	0	0
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	115	222	119	225
Interest income recognized	2	4	4	7
Consumer Portfolio Segment [Member]
Average recorded investment	16	38	17	39
Interest income recognized	$ 0	$ 0	$ 0	$ 0