Document and Entity Information (USD $)	9 Months Ended
	Mar. 24, 2013	Apr. 22, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	INTERNATIONAL RECTIFIER CORP /DE/
Entity Central Index Key	0000316793
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float	$ 1,228,885,481
Entity Common Stock, Shares Outstanding		69,448,496
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 24, 2013