Note 7 - Accrued Retirement Benefits - Changes in Benefit Obligations and Plan Assets (Details) (Parentheticals)	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Pension and Other Postretirement Benefits Cost (Reversal of Cost)	Pension and Other Postretirement Benefits Cost (Reversal of Cost)

Indicates line item in statement of income or comprehensive income that includes interest cost component of net periodic benefit cost (credit) for defined benefit plan.

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-6

Name:	us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration