Note 9 - Fair Values - Losses Resulting From Non-recurring Fair Value Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Losses resulting from nonrecurring fair value adjustments	$ 353	$ 72	$ 504	$ 371
Collateral Dependent Impaired Loans [Member]
Losses resulting from nonrecurring fair value adjustments	353	29	498	328
Other Real Estate Owned [Member]
Losses resulting from nonrecurring fair value adjustments	$ 0	$ 43	$ 6	$ 43