Note 5 - Loans - Average Balance and Interest Income Recognized Related to Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Average Recorded Investment	$ 131,019	$ 162,945	$ 190,226
Contractual interest due	3,462	3,997	5,339
Commercial Portfolio Segment [Member]
Average Recorded Investment	21,199	23,960	26,128
Contractual interest due	767	546	878
Real Estate Construction Portfolio Segment [Member]
Average Recorded Investment	10,362	22,066	32,439
Contractual interest due		261	264
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	81,905	100,118	114,248
Contractual interest due	2,214	2,708	3,735
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Average Recorded Investment	17,553	16,801	17,411
Contractual interest due	$ 481	$ 482	$ 462