Note 3 - Loans - Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans	$ 2,577,960	$ 2,409,570
Commercial and Industrial Portfolio Segment [Member]
Loans	855,015	779,014
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	216,068	195,912
Undevelopment Land Portfolio Segment [Member]
Loans	22,156	18,988
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,441,091	1,376,788
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	622,777	594,902
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	420,999	398,685
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	277,735	262,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	53,257	57,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	66,323	63,981
Consumer Portfolio Segment [Member]
Loans	$ 43,630	$ 38,868