Note 5 - Allowance for Credit Losses - Changes in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021		Sep. 30, 2020	Sep. 30, 2021		Sep. 30, 2020
Beginning balance	$ 31,857		$ 23,758	$ 26,182	[1],[2]	$ 18,425
(Recovery of) provision for credit losses	(1,394)		4,703	(7,625)		12,034
Charge-offs	(1,255)		(1,563)	(4,887)		(4,429)
Recoveries	669		379	3,100		1,247
Net charge-offs	(586)		(1,184)	(1,787)
Ending balance	29,877	[2]	27,277	29,877	[2]	27,277
Net (charge-offs) recoveries						(3,182)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning balance				13,107
(Recovery of) provision for credit losses	(1,394)
Commercial Portfolio Segment [Member]
Beginning balance	17,704		13,909	14,661		10,235
(Recovery of) provision for credit losses			1,972	(6,286)		6,577
Charge-offs	(407)		(501)	(2,366)		(1,647)
Recoveries	285		169	1,709		384
Net charge-offs	(122)		(332)	(657)
Ending balance	16,078		15,549	16,078		15,549
Net (charge-offs) recoveries						(1,263)
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning balance				8,360
(Recovery of) provision for credit losses	(1,504)
Consumer Real Estate Portfolio Segment [Member]
Beginning balance	11,055		7,294	8,951		6,325
(Recovery of) provision for credit losses			1,975	(2,845)		2,899
Charge-offs	(195)		(188)	(253)		(430)
Recoveries	179		38	724		325
Net charge-offs	(16)		(150)	471
Ending balance	10,722		9,119	10,722		9,119
Net (charge-offs) recoveries						(105)
Consumer Real Estate Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning balance				4,145
(Recovery of) provision for credit losses	(317)
Consumer and Other Portfolio Segment [Member]
Beginning balance	3,098		2,555	2,570		1,865
(Recovery of) provision for credit losses			756	1,506		2,558
Charge-offs	(653)		(874)	(2,268)		(2,352)
Recoveries	205		172	667		538
Net charge-offs	(448)		(702)	(1,601)
Ending balance	3,077		$ 2,609	3,077		2,609
Net (charge-offs) recoveries						$ (1,814)
Consumer and Other Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning balance				$ 602
(Recovery of) provision for credit losses	$ 427

[1] Derived from audited financial statements

[2] Effective January 1, 2021, the Company adopted the current expected credit loss methodology ("CECL"), prior to January 1, 2021, the Company utilized the incurred credit loss methodology.