Number of Shares of Tidewater Common Stock Held by Plan (Detail) (Defined Contribution Pension Plan 401k)	Mar. 31, 2015	Mar. 31, 2014
Defined Contribution Pension Plan 401k
Defined Contribution Plan [Line Items]
Number of shares of Tidewater common stock held by 401(k) plan	299,256	273,662

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.

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=6418455&loc=d3e16701-113920

Name:	us-gaap_CommonStockSharesHeldInEmployeeTrustShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant