Note 4 - Loans - Average Balance and Interest Income Recognized Related to Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Average Recorded Investment	$ 91,353	$ 102,583	$ 122,596
Contractual interest due	2,394	2,084	3,166
Commercial Portfolio Segment [Member]
Average Recorded Investment	31,009	37,475	44,486
Contractual interest due	246	412	685
Real Estate Construction Portfolio Segment [Member]
Average Recorded Investment	4,408	4,697	6,835
Contractual interest due	294	0	0
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	41,649	47,612	57,596
Contractual interest due	1,602	1,366	2,125
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Average Recorded Investment	14,287	12,799	13,679
Contractual interest due	$ 252	$ 306	$ 356