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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Average recorded investment	$ 10,486	$ 20,136	$ 10,319	$ 19,026
Interest income recognized	47	73	96	148
Commercial Portfolio Segment [Member]
Average recorded investment	613	1,304	626	1,662
Interest income recognized	9	16	17	32
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	708	11,622	354	10,017
Interest income recognized	0	11	0	23
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	3,284	0	3,193	0
Interest income recognized	0	0	0	0
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	5,440	6,719	5,698	6,797
Interest income recognized	34	41	72	83
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	181	192	184	188
Interest income recognized	0	0	0	0
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	222	277	225	340
Interest income recognized	4	5	7	10
Consumer Portfolio Segment [Member]
Average recorded investment	38	22	39	22
Interest income recognized	$ 0	$ 0	$ 0	$ 0