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Commitments and Contingencies - Additional Information (Detail) - Vessel Commitments $ in Millions | Mar. 31, 2018 USD ($) Vessel T
--- | ---
Significant Purchase and Supply Commitment [Line Items] |
Remaining Balance, commitments | $ | $ 4.2
Number of Vessels, commitments | Vessel | 1
Significant commitment, new construction deadweight tons capacity | T | 5,400

X
- Definition Commitments, remaining expenditures. + References No definition available. + Details
Name: | tdw_CommitmentsRemainingExpenditures
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Significant Commitment New Construction Dead Weight Tons Capacity + References No definition available. + Details
Name: | tdw_SignificantCommitmentNewConstructionDeadWeightTonsCapacity
Namespace Prefix: | tdw_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | instant

X
- Definition Significant commitment number of vessel. + References No definition available. + Details
Name: | tdw_SignificantCommitmentNumberOfVessel
Namespace Prefix: | tdw_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Significant Purchase and Supply Commitment [Line Items] + References No definition available. + Details
Name: | tdw_SignificantPurchaseAndSupplyCommitmentLineItems
Namespace Prefix: | tdw_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=tdw_DeepwaterPlatformSupplyVesselMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |