Document and Entity Information (USD $)	12 Months Ended
	Mar. 31, 2013	Apr. 30, 2013	Sep. 30, 2012
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Trading Symbol	TDW
Entity Registrant Name	TIDEWATER INC
Entity Central Index Key	0000098222
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		49,494,676
Entity Public Float			$ 2,390,575,522