Note 3 - Loans - Internally Assigned Risk Grades of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans	$ 2,335,120	$ 2,305,375
Commercial and Industrial Portfolio Segment [Member]
Loans	750,728	736,841
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	174,310	192,348
Undevelopment Land Portfolio Segment [Member]
Loans	20,989	21,496
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,351,662	1,319,520
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	576,810	538,886
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	397,804	408,292
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	261,707	249,498
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	51,925	55,325
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	63,416	67,519
Consumer Portfolio Segment [Member]
Loans	37,431	35,170
Pass [Member]
Loans	2,288,394	2,267,103
Pass [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	726,194	714,025
Pass [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	174,310	191,455
Pass [Member] | Undevelopment Land Portfolio Segment [Member]
Loans	20,485	21,022
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	1,330,136	1,305,562
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	575,339	538,688
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	383,387	396,997
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	256,458	247,888
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	51,923	55,279
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	63,029	66,710
Pass [Member] | Consumer Portfolio Segment [Member]
Loans	37,269	35,039
Special Mention [Member]
Loans	21,733	22,226
Special Mention [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	7,464	14,266
Special Mention [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans
Special Mention [Member] | Undevelopment Land Portfolio Segment [Member]
Loans
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	14,167	7,960
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	761
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	10,313	7,960
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	3,018
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	2
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	73
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans	102
Substandard [Member] | Performing Financial Instruments [Member]
Loans	18,925	9,339
Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	6,068	6,707
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	14,197	5,850
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	2,873	2,700
Substandard [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans		355
Substandard [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans		538
Substandard [Member] | Undevelopment Land Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	30
Substandard [Member] | Undevelopment Land Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	474	474
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	4,694	3,134
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Commercial Investment [Member]
Loans	420	5
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	2,869	2,111
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	1,172	592
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Home Equity First Lien [Member]
Loans
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Home Equity Junior Lien [Member]
Loans	233	426
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	2,665	2,864
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Commercial Investment [Member]
Loans	290	193
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	1,235	1,224
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	1,059	1,018
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity First Lien [Member]
Loans		46
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity Junior Lien [Member]
Loans	81	383
Substandard [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	4
Substandard [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	56	131
Doubtful [Member]
Loans
Doubtful [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans
Doubtful [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans
Doubtful [Member] | Undevelopment Land Portfolio Segment [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans