Note 5 - Loans - Aging of the Recorded Investment in Loans (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Current		$ 2,829,857	$ 2,537,627
Past due		15,159	10,544
Loans	[1]	2,845,016	2,548,171
Financial Asset, 30 to 59 Days Past Due [Member]
Past due		2,647	5,112
Financial Asset, 60 to 89 Days Past Due [Member]
Past due		467	2,076
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		12,045	3,356
Commercial and Industrial Portfolio Segment [Member]
Current		861,860	832,923
Past due		8,651	601
Loans		870,511	833,524
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		253	197
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		194	200
Commercial and Industrial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		8,204	204
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Current		213,766	224,732
Past due		56	318
Loans	[2]	213,822	225,050
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		6	0
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		50	0
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		0	318
Undevelopment Land Portfolio Segment [Member]
Current		46,360	29,552
Past due		0	540
Loans		46,360	30,092
Undevelopment Land Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		0	66
Undevelopment Land Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		0	0
Undevelopment Land Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		0	474
Real Estate Mortgage Portfolio Segment [Member]
Current		1,660,492	1,402,362
Past due		6,364	9,085
Loans		1,666,856	1,411,447
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Current		735,387	586,884
Past due		1,231	1,726
Loans		736,618	588,610
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Current		470,951	421,143
Past due		2,832	5,230
Loans		473,783	426,373
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Current		332,718	274,547
Past due		1,640	1,470
Loans		334,358	276,017
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Current		48,441	49,321
Past due		179	179
Loans		48,620	49,500
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Current		72,995	70,467
Past due		482	480
Loans		73,477	70,947
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		2,304	4,849
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Investment [Member]
Past due		94	1,382
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due		467	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		1,368	374
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		179	179
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due		196	182
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		219	1,876
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Investment [Member]
Past due		0	107
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due		86	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		33	336
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		0	0
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due		100	56
Real Estate Mortgage Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		3,841	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		1,137	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		2,279	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		239	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		0	0
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		186	242
Consumer Portfolio Segment [Member]
Current		47,379	48,058
Past due		88	0
Loans		47,467	48,058
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due		84	0
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due		4	0
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due		$ 0	$ 0

[1] Total loans are presented inclusive of premiums, discounts, and net loan origination fees and costs.

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