Note 3 - Business Segments and Sales of Products (Details Textual) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Number of Reportable Segments			5
Derivative, Gain (Loss) on Derivative, Net, Total			$ 13,937	$ (4,483)
Financially-settled Forward Contracts [Member]
Derivative, Gain (Loss) on Derivative, Net, Total	$ 5,000	$ 9,600	$ 4,500	$ 12,900

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/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8672-108599

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