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Fair Value Measurements - Additional Information (Detail) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2019 | Dec. 31, 2018
Fair Value Disclosures [Abstract] |  |
Cash equivalents maturity period, days | 90 days |
Spot derivatives outstanding | $ 0 | $ 0

X
- Definition Derivatives outstanding. + References No definition available. + Details
Name: | tdw_DerivativesOutstanding
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Short term deposits maximum maturity period. + References No definition available. + Details
Name: | tdw_ShortTermDepositsMaximumMaturityPeriod
Namespace Prefix: | tdw_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration