Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2015	Jul. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents-short-term	$ 73,645	$ 65,706
Restricted cash and cash equivalents-long-term		2,763
Total restricted cash and cash equivalents	73,645	68,469
Restricted cash and cash equivalents-short-term [Member] | Related to letters of credit [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents-short-term	3,201	665
Restricted cash and cash equivalents-short-term [Member] | IDT Financial Services customer deposits [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents-short-term	70,189	64,415
Restricted cash and cash equivalents-short-term [Member] | Other [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents-short-term	$ 255	$ 626