Document and Entity Information	3 Months Ended
	Oct. 31, 2012	Dec. 04, 2012 Class A Common Stock [Member]	Dec. 04, 2012 Class B Common Stock [Member]
Entity Information [Line Items]
Entity Registrant Name	IDT CORP
Entity Central Index Key	0001005731
Amendment Flag	false
Current Fiscal Year End Date	--07-31
Document Type	10-Q
Document Period End Date	Oct. 31, 2012
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Entity Filer Category	Accelerated Filer
Entity Common Stock Shares Outstanding		1,574,326	21,259,640