Commitments and Contingencies (Details 1) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash and cash equivalents	$ 98,822	$ 91,035
IDT Financial Services Ltd. customer deposits [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash and cash equivalents	98,500	87,613
Related to letters of credit [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash and cash equivalents	122	3,163
Other [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash and cash equivalents	$ 200	$ 259