Note 4 - Defined Benefit Plan (Details Textual) $ in Millions	3 Months Ended
Mar. 31, 2024 USD ($)
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 3

Amount of contribution received by defined benefit plan from employer which increases plan assets.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
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-Subparagraph (d)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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-URI https://asc.fasb.org/1943274/2147480482/715-20-55-18

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
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-Section 50
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-URI https://asc.fasb.org/1943274/2147480506/715-20-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration