Note 4 - Loans and Leases - Aging of the Recorded Investment in Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Current		$ 2,519,801	$ 2,537,627
Past due		5,908	10,544
Loans		2,525,709	2,548,171
Recorded investment greater than 90 days and accruing		454	745	$ 0
Financial Asset, 30 to 59 Days Past Due [Member]
Past due		1,786	5,112
Financial Asset, 60 to 89 Days Past Due [Member]
Past due		395	2,076
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		3,727	3,356
Commercial and Industrial Portfolio Segment [Member]
Current		827,165	832,923
Past due		582	601
Loans		827,747	833,524
Recorded investment greater than 90 days and accruing			12
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		366	197
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		23	200
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		193	204
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Current		216,115	224,732
Past due			318
Loans	[1]	216,115	225,050
Recorded investment greater than 90 days and accruing
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due			318
Undevelopment Land Portfolio Segment [Member]
Current		28,433	29,552
Past due			540
Loans		28,433	30,092
Recorded investment greater than 90 days and accruing
Undevelopment Land Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due			66
Undevelopment Land Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due
Undevelopment Land Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due			474
Real Estate Mortgage Portfolio Segment [Member]
Current		1,402,849	1,402,362
Past due		5,302	9,085
Loans		1,408,151	1,411,447
Recorded investment greater than 90 days and accruing		454	733
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Current		585,673	586,884
Past due		975	1,726
Loans		586,648	588,610
Recorded investment greater than 90 days and accruing		370	99
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Current		426,347	421,143
Past due		1,816	5,230
Loans		428,163	426,373
Recorded investment greater than 90 days and accruing			535
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Current		276,143	274,547
Past due		1,704	1,470
Loans		277,847	276,017
Recorded investment greater than 90 days and accruing		15
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Current		48,498	49,321
Past due		158	179
Loans		48,656	49,500
Recorded investment greater than 90 days and accruing		69
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Current		66,188	70,467
Past due		649	480
Loans		66,837	70,947
Recorded investment greater than 90 days and accruing			99
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		1,396	4,849
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Investment [Member]
Past due		232	1,382
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due		350	2,732
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | One to Four Family Residential [Member]
Past due		594	374
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		49	179
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due		171	182
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		372	1,876
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Investment [Member]
Past due		56	107
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due			1,377
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | One to Four Family Residential [Member]
Past due		252	336
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		40
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due		24	56
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		3,534	2,360
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Investment [Member]
Past due		687	237
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due		1,466	1,121
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | One to Four Family Residential [Member]
Past due		858	760
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		69
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due		454	242
Consumer Portfolio Segment [Member]
Current		45,239	48,058
Past due		24
Loans		45,263	48,058
Recorded investment greater than 90 days and accruing
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		24
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due

[1] Consists of land acquired for development by the borrower, but for which no development has yet taken place.