XML 121 R101.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Number of Tidewater Common Stock Shares, Series A Warrants and Series B Warrants Held by Plan (Detail) - shares | Dec. 31, 2017 | Jul. 31, 2017 | Mar. 31, 2017
--- | --- | --- | ---
Defined Contribution Plan Disclosure [Line Items] |  |  |
Warrants issued | 924,125 |  |
Defined Contribution Savings Plan 401k |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Number of shares of Tidewater common stock held by 401(k) plan | 8,074 |  |
Defined Contribution Savings Plan 401k | Predecessor |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Number of shares of Tidewater common stock held by 401(k) plan |  | 264,504 | 291,957
Defined Contribution Savings Plan 401k | Series A |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Warrants issued | 9,030 |  |
Defined Contribution Savings Plan 401k | Series B |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Warrants issued | 9,762 |  |

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://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 40 -Section 25 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=65888597&loc=d3e16701-113920 + Details
Name: | us-gaap_CommonStockSharesHeldInEmployeeTrustShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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_DefinedContributionPlanDisclosureLineItems
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: |

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: |