IDT Financial Services Holding Limited Assets and Liabilities Held for Sale (Details 1) - USD ($) $ in Thousands	3 Months Ended
Oct. 31, 2018	Oct. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss before income taxes	$ 41	$ (381)
IDT Financial Services Holding Limited [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss before income taxes	(34)	(450)
Loss before income taxes attributable to IDT Corporation	$ (34)	$ (450)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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