Note 12 - Commitments and Contingencies (Details Textual) $ in Millions	Jun. 30, 2022 USD ($)
Accrual for Environmental Loss Contingencies, Ending Balance	$ 2

Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SAB Topic 5.Y.Q1)
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
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-Section 50
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-URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

Reference 5: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (d)(1)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
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-Section 55
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Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant