Schedule of Accumulated Balances for Each Classification of Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ (10,183)
Other comprehensive loss attributable to IDT Corporation	$ (1,862)	$ (1,769)	(905)	$ (1,547)
Ending balance	(11,088)		(11,088)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(9)
Other comprehensive loss attributable to IDT Corporation			(323)
Ending balance	(332)		(332)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(10,174)
Other comprehensive loss attributable to IDT Corporation			(582)
Ending balance	$ (10,756)		$ (10,756)