Note 5 - Loans (Details) - Aging of the Recorded Investment in Loans - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	$ 11,000	$ 15,589
Current	2,022,007	1,852,961
Loans	2,033,007	1,868,550	$ 1,721,350
Recorded investment greater than 90 days and accruing	176	329
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,338	8,508
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	793	1,553
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	7,869	5,528
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,208	5,245
Current	640,190	566,509
Loans	644,398	571,754	510,739
Recorded investment greater than 90 days and accruing	0	1
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	238	3,860
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	327	3
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	3,643	1,382
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	826
Current	134,482	94,907
Loans	134,482	95,733
Recorded investment greater than 90 days and accruing	0	241
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	69
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	757
Undevelopment Land Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Current	21,185	21,268
Loans	21,185	21,268	29,871
Recorded investment greater than 90 days and accruing	0	0
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Real Estate Mortgage Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	6,441	9,457
Current	1,190,970	1,140,942
Loans	1,197,411	1,150,399	1,046,823
Recorded investment greater than 90 days and accruing	176	87
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,757	4,536
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	458	1,532
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,226	3,389
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	708	1,477
Current	481,931	486,345
Loans	482,639	487,822
Recorded investment greater than 90 days and accruing	0	0
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	290	993
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	140	249
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	278	235
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,761	4,273
Current	372,255	336,709
Loans	375,016	340,982
Recorded investment greater than 90 days and accruing	0	0
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	1,272
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	920
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,761	2,081
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,323	3,109
Current	224,252	208,439
Loans	226,575	211,548
Recorded investment greater than 90 days and accruing	176	73
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,147	1,801
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	94	285
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,082	1,023
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	99	14
Current	50,016	43,765
Loans	50,115	43,779
Recorded investment greater than 90 days and accruing	0	14
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	35	0
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	51	0
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	13	14
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	550	584
Current	62,516	65,684
Loans	63,066	66,268
Recorded investment greater than 90 days and accruing	0
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	285	470
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	173	78
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	92	36
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	351	61
Current	35,180	29,335
Loans	35,531	29,396	$ 34,198
Recorded investment greater than 90 days and accruing	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	343	43
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	8	18
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	$ 0	$ 0