IDT Financial Services Ltd. Recent Transactions (Details) - IDT Financial Services Ltd. [Member] € in Millions, $ in Millions	6 Months Ended
	Jan. 31, 2016 USD ($)	Jan. 31, 2016 EUR (€)	Dec. 31, 2015 USD ($)
IDT Financial Services Ltd. Recent Transactions (Textual)
Received cash from MasterCard Europe			$ 4.7
Estimated adjustments to be received	$ 5.1	€ 4.7
Preferred stock [Member]
IDT Financial Services Ltd. Recent Transactions (Textual)
Estimated adjustments to be received	$ 1.8	€ 1.6