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Fair Value Measurements and Disclosures - Additional Information (Detail) $ in Millions	12 Months Ended
	Mar. 31, 2017 USD ($) Contract	Mar. 31, 2016 USD ($) Contract
Derivatives, Fair Value [Line Items]
Cash equivalents maturity period, days	90 days
Number of contracts outstanding | Contract	6	2
Notional value of foreign exchange contract	$ 1.5	$ 1.4
Forward Contracts
Derivatives, Fair Value [Line Items]
Gain (loss) on Derivatives	$ 0.7	$ 0.1

X

- Definition

Notional value equivalent of forward contract.

+ References

No definition available.

+ Details

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Namespace Prefix:	tdw_
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Balance Type:	debit
Period Type:	instant

X

- Definition

Short term deposits maximum maturity period.

+ References

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+ Details

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X

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579245-113959

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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.

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X

- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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