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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Average recorded investment	$ 20,136	$ 11,354	$ 19,026	$ 11,476
Interest income recognized	73	79	148	157
Commercial Portfolio Segment [Member]
Average recorded investment	1,304	2,681	1,662	2,635
Interest income recognized	16	20	32	41
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	11,622	799	10,017	801
Interest income recognized	11	12	23	23
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	6,719	7,237	6,797	7,331
Interest income recognized	41	42	83	83
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	192	185	188	255
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	277	418	340	420
Interest income recognized	5	5	10	10
Consumer Portfolio Segment [Member]
Average recorded investment	22	34	22	34
Interest income recognized