Note 3 - Loans - Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans	$ 2,512,388	$ 2,409,570
Commercial and Industrial Portfolio Segment [Member]
Loans	843,478	779,014
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	215,752	195,912
Undevelopment Land Portfolio Segment [Member]
Loans	20,120	18,988
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,387,278	1,376,788
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	590,942	594,902
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	407,733	398,685
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	272,900	262,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	51,595	57,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	64,108	63,981
Consumer Portfolio Segment [Member]
Loans	$ 45,760	$ 38,868