Note 6 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Annual Limitation Of Companys Ownership Change	$ 15,000
Deferred Tax Assets, Valuation Allowance	532,994	$ 591,720
Undistributed Earnings of Foreign Subsidiaries	220,300
Unrecognized Tax Benefits, Income Tax Penalties Accrued	9,400	13,600
Foreign Tax Credits and Other Tax Attributes			$ 157,700
Unrecognized Tax Benefits, Period Increase (Decrease)	5,800
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	21,000	20,900
Gulf Mark Offshore Inc [Member]
Annual Limitation Of Companys Ownership Change	5,600
Domestic Tax Jurisdiction [Member]
Operating Loss Carryforwards	216,500	320,800
Domestic Tax Jurisdiction [Member] | Foreign Tax Credit [Member]
Tax Credit Carryforward, Amount	406,400
Domestic Tax Jurisdiction [Member] | Expiring in 2035 [Member]
Operating Loss Carryforwards	33,700
Domestic Tax Jurisdiction [Member] | Indefinite Carryforwards [Member]
Operating Loss Carryforwards	182,800
Domestic Tax Jurisdiction [Member] | IRC Section382 Limitation [Member]
Operating Loss Carryforwards	70,100	$ 131,000
Foreign Tax Jurisdiction [Member]
Operating Loss Carryforwards	377,000
Tax Credit Carryforward, Amount	$ 7,400