Note 8 - Debt (Details Textual) $ in Thousands, € in Millions			3 Months Ended		9 Months Ended
	Jul. 07, 2025 USD ($)	Jul. 05, 2023 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 EUR (€)	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Jul. 03, 2023 USD ($)	Nov. 16, 2021 USD ($)
Gain (Loss) on Extinguishment of Debt			$ (27,101)	$ 0	$ (27,101)	$ 0
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	Secured Overnight Financing Rate (SOFR) [Member]
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 25,000
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 250,000
Line of Credit Facility, Minimum Borrowing Commitment	$ 20,000
Line of Credit Facility, Minimum Borrowing Capacity, Percent of Interest-bearing Debt	10.00%
Ratio of Interest-bearing Debt to EBITDA	3
Ratio of Fair Market Value of Collateral to Outstanding Debt	2.5
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member] \| Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member] \| Secured Overnight Financing Rate (SOFR) [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member] \| Margin Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member] \| Minimum [Member] \| Applicable Margin Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	2.50%
Revolving Credit Facility [Member] \| DNB Bank ASA, New York [Member] \| Maximum [Member] \| Applicable Margin Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	3.50%
The 2023 Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage	9.125%
Debt Instrument, Face Amount	$ 650,000
The 2023 Notes [Member] \| Debt Instrument, Redemption, Period One [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
The 2023 Notes [Member] \| Debt Instrument, Redemption, Period Two [Member]
Debt Instrument, Redemption Price, Percentage	104.563%
Vessel Facility Agreements [Member] \| Delivery of Vessels Per Arrangement [Member]
Debt Instrument, Face Amount			$ 26,700		$ 26,700		€ 24.9
Vessel Facility Agreements [Member] \| Minimum [Member] \| Delivery of Vessels Per Arrangement [Member]
Debt Instrument, Interest Rate, Stated Percentage			2.70%		2.70%		2.70%
Vessel Facility Agreements [Member] \| Maximum [Member] \| Delivery of Vessels Per Arrangement [Member]
Debt Instrument, Interest Rate, Stated Percentage			6.30%		6.30%		6.30%
Nordic Bond [Member]
Debt Instrument, Interest Rate, Stated Percentage											8.50%
Debt Instrument, Covenant, Prepayment Premium Percentage											2.55%
Debt Instrument, Covenant, Prepayment Premium Percentage, Increase (Decrease)											0.85%
Nordic Bond [Member] \| GOLP and TMII [Member]
Debt Instrument, Collateral, Percentage of Equity Interests											66.00%
Nordic Bond 1 [Member]
Debt Instrument, Interest Rate, Stated Percentage			9.125%		9.125%		9.125%
Long-Term Debt, Fair Value			$ 697,100		$ 697,100
Secured Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage											8.50%
Long-Term Debt, Fair Value									$ 218,200
Redemption Premium	$ 4,500
Debt Instrument, Face Amount		$ 325,000									$ 175,000
Secured Debt [Member] \| Tranche A Term Loan [Member]
Debt Instrument, Basis Spread on Variable Rate		5.00%
Secured Debt [Member] \| Tranche A Term Loan [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate		8.00%
Secured Debt [Member] \| Tranche B Term Loan [Member]
Debt Instrument, Basis Spread on Variable Rate		3.75%
Unsecured Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage	10.375%		10.375%		10.375%		10.375%		10.375%	10.375%
Long-Term Debt, Fair Value									$ 266,100
Redemption Premium	$ 15,000
Debt Instrument, Face Amount										$ 250,000
Debt Instrument, Covenant, Prepayment Premium Percentage										6.00%
Nordic Bond [Member]
Debt Instrument, Interest Rate, Stated Percentage	8.50%		8.50%		8.50%		8.50%		8.50%
Long-Term Debt, Fair Value									$ 180,800
Extinguished Debt [Member]
Deferred Debt Issuance Cost, Writeoff			$ 7,500
Gain (Loss) on Extinguishment of Debt			$ (27,100)		$ (27,100)

TIDEWATER INC 10-Q