Note 5 - Loans - Average Balance and Interest Income Recognized Related to Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Average Recorded Investment	$ 122,596	$ 127,067	$ 131,019
Contractual interest due	3,166	3,302	3,462
Commercial Portfolio Segment [Member]
Average Recorded Investment	44,486	26,957	21,199
Contractual interest due	685	1,303	767
Real Estate Construction Portfolio Segment [Member]
Average Recorded Investment	6,835	26,695	10,362
Contractual interest due
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	57,596	58,635	81,905
Contractual interest due	2,125	1,618	2,214
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Average Recorded Investment	13,679	14,780	17,553
Contractual interest due	$ 356	$ 381	$ 481