Note 5 - Loans - Internally Assigned Risk Grades of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans	$ 2,305,375	$ 2,033,007	$ 1,868,550
Pass [Member]
Loans	2,267,103	1,971,727
Special Mention [Member]
Loans	22,226	41,178
Substandard [Member] | Performing Financial Instruments [Member]
Loans	9,339	11,173
Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	6,707	8,929
Doubtful [Member]
Loans
Commercial and Industrial Portfolio Segment [Member]
Loans	736,841	644,398	571,754
Commercial and Industrial Portfolio Segment [Member] | Pass [Member]
Loans	714,025	612,853
Commercial and Industrial Portfolio Segment [Member] | Special Mention [Member]
Loans	14,266	19,672
Commercial and Industrial Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member]
Loans	5,850	7,238
Commercial and Industrial Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	2,700	4,635
Commercial and Industrial Portfolio Segment [Member] | Doubtful [Member]
Loans
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	192,348	134,482	95,733
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Pass [Member]
Loans	191,455	133,342
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Special Mention [Member]
Loans		773
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member]
Loans	355	367
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	538
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Doubtful [Member]
Loans
Undevelopment Land Portfolio Segment [Member]
Loans	21,496	21,185	21,268
Undevelopment Land Portfolio Segment [Member] | Pass [Member]
Loans	21,022	20,513
Undevelopment Land Portfolio Segment [Member] | Special Mention [Member]
Loans		517
Undevelopment Land Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member]
Loans		155
Undevelopment Land Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	474
Undevelopment Land Portfolio Segment [Member] | Doubtful [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,319,520	1,197,411	1,150,399
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	538,886	436,989
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	408,292	420,666
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	249,498	226,575
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	55,325	50,115
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	67,519	63,066
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member]
Loans	1,305,562	1,169,556
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member] | Commercial Investment [Member]
Loans	538,688	434,528
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member] | Owner Occupied Commercial [Member]
Loans	396,997	397,357
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member] | One to Four Family Residential [Member]
Loans	247,888	224,645
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member] | Home Equity First Lien [Member]
Loans	55,279	50,102
Real Estate Mortgage Portfolio Segment [Member] | Pass [Member] | Home Equity Junior Lien [Member]
Loans	66,710	62,924
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member]
Loans	7,960	20,216
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member] | Commercial Investment [Member]
Loans		2,183
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member] | Owner Occupied Commercial [Member]
Loans	7,960	17,135
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member] | One to Four Family Residential [Member]
Loans		848
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member] | Home Equity First Lien [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Special Mention [Member] | Home Equity Junior Lien [Member]
Loans		50
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member]
Loans	3,134	3,413
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member] | Commercial Investment [Member]
Loans	5
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	2,111	3,413
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	592
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member] | Home Equity First Lien [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member] | Home Equity Junior Lien [Member]
Loans	426
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	2,864	4,226
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member] | Commercial Investment [Member]
Loans	193	278
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	1,224	2,761
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	1,018	1,082
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member] | Home Equity First Lien [Member]
Loans	46	13
Real Estate Mortgage Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member] | Home Equity Junior Lien [Member]
Loans	383	92
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member] | Commercial Investment [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member] | Owner Occupied Commercial [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member] | One to Four Family Residential [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member] | Home Equity First Lien [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] | Doubtful [Member] | Home Equity Junior Lien [Member]
Loans
Consumer Portfolio Segment [Member]
Loans	35,170	35,531	$ 29,396
Consumer Portfolio Segment [Member] | Pass [Member]
Loans	35,039	35,463
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member] | Performing Financial Instruments [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	131	68
Consumer Portfolio Segment [Member] | Doubtful [Member]
Loans