Note 5 - Loans - Internally Assigned Risk Grades of Loans (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
Pass [Member]
Loans	2,493,020	2,356,343
Pass [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	803,073	751,628
Pass [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	220,532	195,248
Pass [Member] | Undevelopment Land Portfolio Segment [Member]
Loans	29,618	18,484
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	1,391,739	1,352,236
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	586,543	591,232
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	411,722	383,455
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	273,537	256,968
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	49,500	57,110
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	70,437	63,471
Pass [Member] | Consumer Portfolio Segment [Member]
Loans	48,058	38,747
Special Mention [Member]
Loans	28,354	27,155
Special Mention [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	11,516	12,032
Special Mention [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	4,200
Special Mention [Member] | Undevelopment Land Portfolio Segment [Member]
Loans
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	12,638	15,006
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	1,815	3,599
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	9,030	8,683
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	1,544	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	249	247
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans		117
Substandard [Member] | Performing Financial Instruments [Member]
Loans	23,399	18,690
Substandard [Member] | Nonperforming Financial Instruments [Member]
Loans	3,398	7,382
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	18,703	14,178
Substandard [Member] | Commercial and Industrial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	232	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	318	664
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	4,696	4,478
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Commercial Investment [Member]
Loans	15	19
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	4,500	3,215
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Performing Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	162	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	19	230
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	2,374	5,068
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Commercial Investment [Member]
Loans	237	52
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Owner Occupied Commercial [Member]
Loans	1,121	3,332
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | One to Four Family Residential [Member]
Loans	774	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	242	33
Substandard [Member] | Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans		4
Substandard [Member] | Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans
Doubtful [Member]
Loans	2,548,171	2,409,570
Doubtful [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans	833,524	779,014
Doubtful [Member] | Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Loans	225,050	195,912
Doubtful [Member] | Undevelopment Land Portfolio Segment [Member]
Loans	30,092	18,988
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member]
Loans	1,411,447	1,376,788
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Loans	588,610	594,902
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Loans	426,373	398,685
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Loans	276,017	262,110
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Loans	49,500	57,110
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Loans	70,947	63,981
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans	$ 48,058	$ 38,868