Note 4 - Loans - Average Balance and Interest Income Recognized Related to Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Average Recorded Investment	$ 102,583	$ 122,596	$ 127,067
Contractual interest due	2,084	3,166	3,302
Commercial Portfolio Segment [Member]
Average Recorded Investment	37,475	44,486	26,957
Contractual interest due	412	685	1,303
Real Estate Construction Portfolio Segment [Member]
Average Recorded Investment	4,697	6,835	26,695
Contractual interest due	0	0	0
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	47,612	57,596	58,635
Contractual interest due	1,366	2,125	1,618
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Average Recorded Investment	12,799	13,679	14,780
Contractual interest due	$ 306	$ 356	$ 381