Note 3 - Loans - Internally Assigned Risk Grades of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans	$ 2,512,388	$ 2,409,570
Commercial and Industrial Portfolio Segment [Member]
Loans	843,478	779,014
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	215,752	195,912
Undevelopment Land Portfolio Segment [Member]
Loans	20,120	18,988
Real Estate Mortgage Portfolio Segment [Member]
Loans	1,387,278	1,376,788
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	590,942	594,902
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	407,733	398,685
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	272,900	262,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	51,595	57,110
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	64,108	63,981
Consumer Portfolio Segment [Member]
Loans	45,760	38,868
Pass [Member]
Loans	2,452,205	2,356,343
Pass [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	811,544	751,628
Pass [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	215,082	195,248
Pass [Member] | Undevelopment Land Portfolio Segment [Member]
Loans	19,520	18,484
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	1,360,506	1,352,236
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	588,075	591,232
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	388,799	383,455
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	268,441	256,968
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	51,595	57,110
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	63,596	63,471
Pass [Member] | Consumer Portfolio Segment [Member]
Loans	45,553	38,747
Special Mention [Member]
Loans	30,791	27,155
Special Mention [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	14,275	12,032
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	16,404	15,006
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	2,741	3,599
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	11,678	8,683
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	1,884	2,477
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	101	247
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans	112	117
Substandard [Member] | Performing Financial Instruments [Member]
Loans	17,127	18,690
Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	12,265	7,382
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	13,509	14,178
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	4,150	1,176
Substandard [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans
Substandard [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	670	664
Substandard [Member] | Undevelopment Land Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	30	30
Substandard [Member] | Undevelopment Land Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	570	474
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	3,584	4,478
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Commercial Investment [Member]
Loans	126	19
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	2,107	3,215
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	969	1,014
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	382	230
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	6,784	5,068
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Commercial Investment [Member]
Loans		52
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	5,149	3,332
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	1,606	1,651
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity First Lien [Member]
Loans
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity Junior Lien [Member]
Loans	29	33
Substandard [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	4	4
Substandard [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	91
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