XML 101 R81.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Employee Retirement Plans - Additional Information (Detail) kr in Millions |  |  |  |  | 1 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 02, 2016 | Dec. 31, 2015 | Dec. 01, 2015 USD ($) | Nov. 30, 2015 | Apr. 30, 2018 USD ($) | Dec. 31, 2017 Person | Dec. 31, 2010 Person | Dec. 31, 2017 USD ($) Person | Dec. 31, 2017 NOK (kr) Person | Mar. 31, 2017 USD ($) | Mar. 31, 2017 NOK (kr) | Mar. 31, 2016 USD ($) | Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of employers participated in defined benefit plan | Person |  |  |  |  |  | 4 | 60 |  |  |  |  |  |
Number of employers still remains in defined benefit plan | Person |  |  |  |  |  |  |  | 30 | 30 |  |  |  |
Percentage of defined benefit plan, actuarial discount rate assumption |  |  |  |  |  |  |  | 3.80% | 3.80% |  |  |  |
Defined benefit plan, significant concentrations of risk |  |  |  |  |  |  |  | U.S. Plans The pension plan and the supplemental plan assets are periodically evaluated for concentration risks. As of December 31, 2017, the company did not have any individual asset investments that comprised 10% or more of each plan’s overall assets. | U.S. Plans The pension plan and the supplemental plan assets are periodically evaluated for concentration risks. As of December 31, 2017, the company did not have any individual asset investments that comprised 10% or more of each plan’s overall assets. |  |  |  |
Defined benefit plan, concentration risk, assets, equity securities, difference plan assets and liabilities |  |  |  |  |  |  |  | 15.00% | 15.00% |  |  |  |
Defined benefit plan, concentration risk, assets, equity securities, maximum foreign and us stock |  |  |  |  |  |  |  | 10.00% | 10.00% |  |  |  |
Defined benefit plan, concentration risk, diversification, equity limit, single industry |  |  |  |  |  |  |  | 25.00% | 25.00% |  |  |  |
Defined benefit plan, concentration risk, diversification, equity limit, single corporation |  |  |  |  |  |  |  | 10.00% | 10.00% |  |  |  |
Defined benefit plan, concentration risk, diversification, debt limit, single issuer |  |  |  |  |  |  |  | 10.00% | 10.00% |  |  |  |
Defined contribution plan, description |  |  |  |  |  |  |  | Effective January 1, 2018, the company no longer provides a matching of 50% of the first 8% of eligible compensation in an attempt to reduce costs. | Effective January 1, 2018, the company no longer provides a matching of 50% of the first 8% of eligible compensation in an attempt to reduce costs. |  |  |  |
Retirement Contributions |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage |  |  |  |  |  |  |  | 3.00% | 3.00% |  |  |  |
Defined contribution plan, company contribution, vesting period, years |  |  |  |  |  |  |  | 5 years | 5 years |  |  |  |
Retirement Contributions | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage additional percentage |  |  |  |  |  |  |  | 1.00% | 1.00% |  |  |  |
Retirement Contributions | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage additional percentage |  |  |  |  |  |  |  | 8.00% | 8.00% |  |  |  |
Defined Contribution Savings Plan 401k |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution, vesting period, years |  |  |  |  |  |  |  | 5 years | 5 years |  |  |  |
Percentage of defined plan, minimum employee contribution |  |  |  |  |  | 2.00% |  | 2.00% | 2.00% |  |  |  |
Percentage of defined plan, maximum employee contribution |  |  |  |  |  | 75.00% |  | 75.00% | 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% |  |  |  |  |  |  |  |  |  |  |
Non-Qualified Supplemental Savings Plan Executives |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage match, common stock |  |  |  |  |  |  |  |  |  | 50.00% | 50.00% |  |
Deferred compensation arrangement with individual, deferred compensation percentage |  |  |  |  |  |  |  |  |  | 50.00% | 50.00% |  |
Deferred compensation arrangement with individual, deferred bonus percentage |  |  |  |  |  |  |  |  |  | 100.00% | 100.00% |  |
Defined contribution plan, restoration benefit |  |  |  |  |  |  |  |  |  | 3.00% | 3.00% |  |
Non-Qualified Supplemental Savings Plan Executives | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage additional percentage |  |  |  |  |  |  |  |  |  | 1.00% | 1.00% |  |
Non-Qualified Supplemental Savings Plan Executives | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution percentage additional percentage |  |  |  |  |  |  |  |  |  | 8.00% | 8.00% |  |
Multinational Retirement Plan |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined contribution plan, company contribution, vesting period, years |  |  | 5 years | 6 years |  |  |  |  |  |  |  |  |
Percentage of defined plan, minimum employee contribution |  |  | 1.00% | 1.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, maximum employee contribution |  |  | 50.00% | 15.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, company contribution match, cash |  |  | 50.00% | 50.00% |  |  |  |  |  |  |  |  |
Percentage of defined plan, company contribution match, employee deferred compensation |  |  | 6.00% | 6.00% |  |  |  |  |  |  |  |  |
Reduction in defined plan assets and liabilities |  |  | $ 6,400,000 |  |  |  |  |  |  |  |  |  |
Norway?s Defined Benefit Pension Plan |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of employers still remains in defined benefit plan | Person |  |  |  |  |  |  |  | 90 | 90 |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  |  |  |  | $ 300,000 | kr 2.7 | $ 400,000 | kr 3.6 |  |
Pension Plans, Defined Benefit |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  |  |  |  | 0 |  | 3,000,000 |  | $ 0 |
Supplemental Executive Retirement Plan |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  |  |  |  |  |  | $ 100,000 |  | 200,000 |  |  |
Supplemental Executive Retirement Plan | Scenario, Forecast | President, and Chief Executive Officer [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of distribution |  |  |  |  | $ 9,600,000 |  |  |  |  |  |  |  |
Settlement loss |  |  |  |  | $ 500,000 |  |  |  |  |  |  |  |
Postretirement Benefit Plan |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Additional estimated net periodic benefit |  |  |  |  |  |  |  |  |  | $ 2,000,000 |  |  |
Postretirement Benefit Plan | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
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, Actuarial Discount Rate Assumption + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanActuarialDiscountRateAssumption
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, Concentration Risk, Diversification, Debt Limit, Single Issuer + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanConcentrationRiskDiversificationDebtLimitSingleIssuer
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Concentration Risk, Diversification, Equity Limit, Single Corporation + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanConcentrationRiskDiversificationEquityLimitSingleCorporation
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Concentration Risk, Diversification, Equity Limit, Single Industry + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanConcentrationRiskDiversificationEquityLimitSingleIndustry
Namespace Prefix: | tdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Number of Employees Participating + References No definition available. + Details
Name: | tdw_DefinedBenefitPlanNumberOfEmployeesParticipating
Namespace Prefix: | tdw_
Data Type: | xbrli:positiveIntegerItemType
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 Additional Percentage + References No definition available. + Details
Name: | tdw_DefinedContributionPlanCompanyContributionPercentageAdditionalPercentage
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 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 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 Reduction in benefit plan assets and liabilities. + References No definition available. + Details
Name: | tdw_ReductionInDefinedPlanAssetsAndLiabilities
Namespace Prefix: | tdw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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 Amount of contribution received by defined benefit plan from employer which increases plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5)(ii) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2709-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5)(iv)(01) -URI http://asc.fasb.org/extlink&oid=82843861&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 of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanPlanAmendments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Narrative that provides an understanding of significant concentrations of risk within plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(i) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2446-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanSignificantConcentrationsOfRisk
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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://www.xbrl.org/2003/role/presentationRef -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
- Details
Name: | us-gaap_RetirementPlanNameAxis=tdw_RetirementPlansContributionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
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_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_NorwaysDefinedBenefitPensionPlanMember
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: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_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: |