Note 11 - Employee Retirement Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liquidity Risk Long-term Investments In Private Equity and Real Estate		1.00%
Defined Contribution Plan, Cost	$ 118,000	$ 117,000	$ 98,000
Defined Benefit Plan, Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50.00%
Bond Investments [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50.00%
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage	42.00%
Minimum [Member]
Percent To Yield	10.00%
Maximum [Member]
Percent To Yield	40.00%
Pension Plan [Member]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ (100,000)	1,100,000
Defined Benefit Plan, Accumulated Benefit Obligation	3,700,000	3,500,000
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Voluntary Contributions by Employer	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 18,000	$ 15,000
Weighted Average Discount Rate, Rounded Amount	0.34%	2.63%
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Voluntary Contributions by Employer	$ 25,000	$ 0
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	11,000
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 32,000	$ 8,000
Weighted Average Discount Rate, Rounded Amount	0.16%	1.26%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 26,000	$ 31,000
Cap On Contribution Toward Future Retiree Medical Coverage	120.00%
Percentage Of Cost To Be Paid By Employees For Retiree Medical Upon Retirement	100.00%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 7,000	$ 209,000
Weighted Average Discount Rate, Rounded Amount	34.00%	2.59%
Other Postretirement Benefits Plan [Member] | UNITED STATES
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0	$ 0