Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Consolidated Statements of Comprehensive Income [Abstract]
NET INCOME	$ 9,641	$ 25,358	$ 86,115
Other comprehensive income (loss):
Change in unrealized gain (loss) on available-for-sale securities	2,126	583	(567)
Foreign currency translation adjustments	(725)	(6,127)	(2,432)
Other comprehensive income (loss)	1,401	(5,544)	(2,999)
COMPREHENSIVE INCOME	11,042	19,814	83,116
Comprehensive income attributable to noncontrolling interests	(1,464)	(1,844)	(1,625)
COMPREHENSIVE INCOME ATTRIBUTABLE TO IDT CORPORATION	$ 9,578	$ 17,970	$ 81,491