Note 3 - Loans - Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans	$ 2,534,483	$ 2,409,570
Commercial and Industrial Portfolio Segment [Member]
Loans	816,252	779,014
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	211,415	195,912
Undevelopment Land Portfolio Segment [Member]
Loans	21,692	18,988
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,437,674	1,376,788
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	630,000	594,902
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	420,098	398,685
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	274,409	262,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	46,062	57,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	67,105	63,981
Consumer Portfolio Segment [Member]
Loans	$ 47,450	$ 38,868