Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Net loss	$ (1,148)	$ (1,797)
Other comprehensive income (loss):
Change in unrealized gain on available-for-sale securities	(2)	(30)
Foreign currency translation adjustments	524	(368)
Other comprehensive income (loss)	522	(398)
Comprehensive loss	(626)	(2,195)
Comprehensive income attributable to noncontrolling interests	(301)	(295)
Comprehensive loss attributable to IDT Corporation	$ (927)	$ (2,490)