Document and Entity Information - shares	3 Months Ended
	Oct. 31, 2015	Dec. 06, 2015
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, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Entity Filer Category	Accelerated Filer
Class A common stock
Entity Common Stock Shares Outstanding		1,574,326
Class B common stock
Entity Common Stock Shares Outstanding		21,752,240