Note 12 - Segment Information (Details Textual) $ in Thousands	6 Months Ended
Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)
Number of Reportable Segments	2
Number of RINs in Inventory	2,100,000	4,300,000	11,800,000
RIN, Fair Market Value	$ 1,055	$ 6,567	$ 19,461
RIN, Cost	$ 0	$ 0	$ 0
Chemicals [Member]
Number of Reportable Segments	2

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-18

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration