Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 4,663	$ 2,757	$ 9,240	$ 83,111
Other comprehensive (loss) income:
Change in unrealized gain on available-for-sale securities	(143)	8	385	15
Foreign currency translation adjustments	(4,011)	(2,119)	(3,900)	(3,977)
Other comprehensive loss	(4,154)	(2,111)	(3,515)	(3,962)
Comprehensive income	509	646	5,725	79,149
Comprehensive income attributable to noncontrolling interests	(598)	(247)	(981)	(445)
Comprehensive (loss) income attributable to IDT Corporation	$ (89)	$ 399	$ 4,744	$ 78,704