Note 5 - Loans - Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans	$ 2,409,570	$ 2,305,375	$ 2,033,007
Commercial and Industrial Portfolio Segment [Member]
Loans	779,014	736,841	644,398
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	195,912	192,348	134,482
Undevelopment Land Portfolio Segment [Member]
Loans	18,988	21,496	21,185
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,376,788	1,319,520	1,197,411
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	594,902	538,886
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	398,685	408,292
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	262,110	249,498
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	57,110	55,325
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	63,981	67,519
Consumer Portfolio Segment [Member]
Loans	$ 38,868	$ 35,170	$ 35,531