Document and Entity Information	9 Months Ended
	Apr. 30, 2013	Jun. 04, 2013 Class A common stock	Jun. 04, 2013 Class B common stock
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	Apr. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Entity Filer Category	Accelerated Filer
Entity Common Stock Shares Outstanding		1,574,326	21,324,715