Document and Entity Information (USD $)	12 Months Ended
	Jun. 24, 2012	Aug. 16, 2012	Dec. 25, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	INTERNATIONAL RECTIFIER CORP /DE/
Entity Central Index Key	0000316793
Current Fiscal Year End Date	--06-24
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,379,394,366
Entity Common Stock, Shares Outstanding		69,328,152
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 24, 2012