Document and Entity Information	6 Months Ended
	Jan. 31, 2013	Mar. 06, 2013 Class A Common Stock [Member]	Mar. 06, 2013 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	Jan. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Entity Filer Category	Accelerated Filer
Entity Common Stock Shares Outstanding		1,574,326	21,276,304