Note 7 - Accrued Retirement Benefits (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan, Plan Assets, Benefits Paid		$ 12,416,000	$ 2,314,000
Defined Benefit Plan, Plan Assets, Amount		$ 0	11,441,000	$ 13,860,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction Period (Day)		105 days
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year		$ 1,060,000	0
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year		1,060,000	$ 0
Defined Benefit Plan, Settlement Expense		6,556,000
Pension Expense (Reversal of Expense), Noncash	$ 587,000	6,556,000
Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Benefits Paid		$ 12,400,000