XML 54 R91.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Employee Retirement Plans - Additional Information (Detail) |  | 1 Months Ended | 4 Months Ended | 5 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Dec. 01, 2015 | Apr. 30, 2018 USD ($) | Jul. 31, 2017 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) Person shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 shares | Aug. 01, 2017 shares
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined benefit plan, concentration risk, assets, equity securities, difference plan assets and liabilities |  |  |  |  |  |  | 15.00% |  |  |
Defined benefit plan, concentration risk, assets, equity securities, maximum foreign and us stock |  |  |  |  |  |  | 10.00% |  |  |
Defined benefit plan, significant concentrations of risk |  |  |  |  |  |  | The pension plan assets are periodically evaluated for concentration risks. As of December 31, 2019, we did not have any individual asset investments that comprised 10% or more of each plan’s overall assets. |  |  |
Unrecognized actuarial (loss) gain |  |  |  |  |  |  | $ 0 |  |  |
Unrecognized prior service credit (cost) |  |  |  |  |  |  | $ 0 |  |  |
Discount rates |  |  |  |  |  |  | 3.50% | 4.50% |  |
Defined contribution plan, description |  |  |  |  |  |  | Effective January 1, 2018, we no longer provide a matching of 50% of the first 8% of eligible compensation in an attempt to reduce costs. |  |  |
Number of shares of Tidewater common stock held by 401(k) plan | shares |  |  | 264,504 |  |  |  |  |  |  |
Number of shares of Tidewater Series warrants held by 401(k) plan | shares |  |  |  | 924,125 | 924,125 |  |  |  | 924,125 |
Norways Defined Benefit Pension Plan |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  | $ 300,000 |  | $ 700,000 | $ 200,000 |  |
Number of employers still remains in defined benefit plan | Person |  |  |  |  |  |  | 100 |  |  |
Norways Defined Benefit Pension Plan | Scenario, Forecast |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  |  | $ 500,000 |  |  |  |
Retirement Contributions |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage |  |  |  |  |  |  | 3.00% |  |  |
Defined contribution plan, company contribution, vesting period, years |  |  |  |  |  |  | 5 years |  |  |
Defined Contribution Savings Plan 401k |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution, vesting period, years |  |  |  |  |  |  | 5 years |  |  |
Percentage of defined plan, minimum employee contribution |  |  |  |  |  |  | 2.00% |  |  |
Percentage of defined plan, maximum employee contribution |  |  |  |  |  |  | 75.00% |  |  |
Percentage of defined plan, company contribution match, cash |  |  |  |  |  |  |  |  | 50.00% |
Percentage of defined plan, company contribution match, employee deferred compensation |  |  |  |  |  |  | 8.00% |  | 8.00% |
Defined contribution plan, company contribution percentage match, company stock |  |  |  |  |  |  | 50.00% |  |  |
Number of shares of Tidewater common stock held by 401(k) plan | shares |  |  |  | 8,074 | 8,074 |  | 0 | 7,075 | 8,074 |
Defined Contribution Plan Expense |  |  | $ 900,000 | $ 900,000 |  |  |  |  |  |
Defined Contribution Savings Plan 401k | Series A Warrants |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares of Tidewater Series warrants held by 401(k) plan | shares |  |  |  |  |  |  |  |  |  | 9,030
Defined Contribution Savings Plan 401k | Series B Warrents |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares of Tidewater Series warrants held by 401(k) plan | shares |  |  |  | 9,762 | 9,762 |  |  |  | 9,762 |
Non-Qualified Supplemental Savings Plan Executives |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage match, common stock |  |  |  |  |  |  |  | 50.00% |  |
Deferred compensation arrangement with individual, deferred compensation percentage |  |  |  |  |  |  |  | 50.00% |  |
Deferred compensation arrangement with individual, deferred bonus percentage |  |  |  |  |  |  |  | 100.00% |  |
Defined contribution plan, restoration benefit |  |  |  |  |  |  | 3.00% |  |  |
Multinational Retirement Plan |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution, vesting period, years | 5 years |  |  |  |  |  |  |  |  |
Percentage of defined plan, minimum employee contribution | 1.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, maximum employee contribution | 50.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, company contribution match, cash | 50.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, company contribution match, employee deferred compensation | 6.00% |  |  |  |  |  |  |  |  |
Merchant Navy Officers Pension Fund |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Multi-employer retirement fund liability |  |  |  |  |  |  | $ 1,000,000.0 | $ 1,400,000 |  |
Multi-employer retirement fund expense |  |  |  |  |  |  | 200,000 |  |  |
Pension Plans, Defined Benefit |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  | $ 0 |  | 1,100,000 | 0 |  |
Supplemental Executive Retirement Plan |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  | $ 100,000 |  | 3,200,000 | 900,000 |  |
Supplemental Executive Retirement Plan | President, and Chief Executive Officer |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Settlement of distribution |  | $ 8,900,000 |  |  |  |  |  |  |  |
Settlement loss |  | $ (300,000) |  |  |  |  |  |  |  |
Postretirement Benefit Plan |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |
Gain on termination of post retirement benefit plan |  |  |  |  |  |  |  | $ 4,000,000.0 |  |
Postretirement benefit plan obligations reduction |  |  |  |  |  |  | $ 1,900,000 |  |  |

X
- Definition Deferred Compensation Arrangement with Individual Deferred Bonus Percentage + References No definition available. + Details
Name: | tdw_DeferredCompensationArrangementWithIndividualDeferredBonusPercentage
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred Compensation Arrangement with Individual Deferred Compensation Percentage + References No definition available. + Details
Name: | tdw_DeferredCompensationArrangementWithIndividualDeferredCompensationPercentage
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Concentration Risk, Assets, Equity Securities, Difference plan assets and liabilities. + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanConcentrationRiskAssetsEquitySecuritiesDifferencePlanAssetsAndLiabilities
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Concentration Risk, Assets, Equity Securities, Maximum of Foreign and US Stock + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanConcentrationRiskAssetsEquitySecuritiesMaximumOfForeignAndUsStock
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined benefit plan number of employees remaining in plan. + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanNumberOfEmployeesRemainingInPlan
Namespace Prefix: | tdw_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan Company Contribution Percentage + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionPercentage
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined contribution plan company contribution percentage match cash. + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionPercentageMatchCash
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan Company Contribution Percentage Match Common Stock + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionPercentageMatchCommonStock
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined contribution plan company contribution percentage match deferred compensation. + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionPercentageMatchDeferredCompensation
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan, Company Contribution Vesting Period + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionVestingPeriod
Namespace Prefix: | tdw_
Data Type: | xbrli:durationItemType
Balance Type: | na
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 Defined contribution plan percent contributed by employee maximum. + References No definition available. + Details
Name: | tdw_DefinedContributionPlanPercentContributedByEmployeeMaximum
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Contribution Plan Percent Contributed By Employee Minimum + References No definition available. + Details
Name: | tdw_DefinedContributionPlanPercentContributedByEmployeeMinimum
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Contribution Plan, Restoration Benefit + References No definition available. + Details
Name: | tdw_DefinedContributionPlanRestorationBenefit
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gain on termination of post retirement benefit plan. + References No definition available. + Details
Name: | tdw_GainOnTerminationOfPostRetirementBenefitPlan
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Postretirement benefit plan obligations reduction. + References No definition available. + Details
Name: | tdw_PostretirementBenefitPlanObligationsReduction
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees but not yet earned. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 40 -Section 25 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=109244457&loc=d3e16701-113920 + Details
Name: | us-gaap_CommonStockSharesHeldInEmployeeTrustShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of distribution made to individual in accordance with deferred compensation arrangement. + References No definition available. + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualDistributionPaid
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of contribution received by defined benefit plan from employer which increases plan assets. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
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
- Definition Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (s) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount included in accumulated other comprehensive (income) loss for prior service cost (credit) expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (s) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Description of investment policy and strategy for defined benefit plan asset. Includes, but is not limited to, investment allocation decision and factor pertinent to understanding investment policy and strategy for plan asset. Factor includes, but is not limited to, investment goal, risk management practice, permitted and prohibited investment including use of derivative, diversification, and relationship between plan asset and obligation. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanInvestmentPoliciesAndStrategiesNarrativeDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 + Details
Name: | us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of nature and effect of change affecting comparability of defined contribution plan. Includes, but is not limited to, change in rate of employer contributions, business combination, or divestiture. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DescriptionOfNatureAndEffectOfSignificantChangesDuringPeriodAffectingComparability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying amount as of the balance sheet date of the obligations recognized for the various benefits provided to former or inactive employees, their beneficiaries, and covered dependents after employment but before retirement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 712 -SubTopic 10 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6410138&loc=d3e79708-111665 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 712 -SubTopic 10 -Section 25 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6410138&loc=d3e79691-111665 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period expense related to postemployment benefits. + References No definition available. + Details
Name: | us-gaap_PostemploymentBenefitsPeriodExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=us-gaap_SeriesAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=us-gaap_SeriesBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_OfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_DefinedBenefitPostretirementHealthCoverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |