Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 1,257	$ 4,663	$ 23,552	$ 9,240
Other comprehensive income (loss):
Change in unrealized (loss) gain on available-for-sale securities	(40)	(143)	(63)	385
Foreign currency translation adjustments	459	(4,011)	(2,403)	(3,900)
Other comprehensive income (loss)	419	(4,154)	(2,466)	(3,515)
Comprehensive income	1,676	509	21,086	5,725
Comprehensive income attributable to noncontrolling interests	(382)	(598)	(758)	(981)
Comprehensive income (loss) attributable to IDT Corporation	$ 1,294	$ (89)	$ 20,328	$ 4,744