Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Statements Of Comprehensive Income (Loss) [Abstract]
Net income (loss)	$ 3,495	$ 2,929	$ 7,663	$ (2,144)
Other comprehensive income (loss):
Change in unrealized gain on available-for-sale securities		6		4
Foreign currency translation adjustments	1,645	(2,035)	3,273	(2,829)
Other comprehensive income (loss)	1,645	(2,029)	3,273	(2,825)
Comprehensive income (loss)	5,140	900	10,936	(4,969)
Comprehensive (income) loss attributable to noncontrolling interests	(503)	(266)	(1,049)	469
Comprehensive income (loss) attributable to IDT Corporation	$ 4,637	$ 634	$ 9,887	$ (4,500)