Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 13,205	$ 904	$ 21,620	$ (518)
Other comprehensive income (loss):
Change in unrealized loss on available-for-sale securities	46		17
Foreign currency translation adjustments	(1,815)	(513)	(1,564)	(1,717)
Other comprehensive loss	(1,769)	(513)	(1,547)	(1,717)
Comprehensive income (loss)	11,436	391	20,073	(2,235)
Comprehensive (income) loss attributable to noncontrolling interests	(97)	28	(224)	(63)
Comprehensive income (loss) attributable to IDT Corporation	$ 11,339	$ 419	$ 19,849	$ (2,298)