Note 5 - Loans - Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans	$ 2,548,171	$ 2,409,570	$ 2,305,375
Commercial and Industrial Portfolio Segment [Member]
Loans	833,524	779,014	736,841
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	225,050	195,912	192,348
Undevelopment Land Portfolio Segment [Member]
Loans	30,092	18,988	21,496
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,411,447	1,376,788	1,319,520
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	588,610	594,902
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	426,373	398,685
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	276,017	262,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	49,500	57,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	70,947	63,981
Consumer Portfolio Segment [Member]
Loans	$ 48,058	$ 38,868	$ 35,170