XML 117 R100.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Amounts Charged to Expense Related to Defined Contribution Plans (Detail) - USD ($) $ in Thousands | 4 Months Ended | 5 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2018 | Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined contribution plans expense, net of forfeitures |  |  | $ 3 |
Defined contribution plans forfeitures |  |  | $ 152 |
Defined Contribution Savings Plan 401k |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined contribution plans expense, net of forfeitures |  | $ 854 |  |
Defined contribution plans forfeitures |  | $ 83 |  |
Defined Contribution Savings Plan 401k | Predecessor |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined contribution plans expense, net of forfeitures | $ 871 |  |  | $ 2,660
Defined contribution plans forfeitures | $ 79 |  |  | $ 149

X
- Definition Defined Benefit Plan Forfeited Amounts + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanForfeitedAmounts
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined Contribution Plan Expense + References No definition available. + Details
Name: | tdw_DefinedContributionPlanExpense
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=tdw_DefinedContributionSavingPlanFourZeroOneKMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |