Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Apr. 30, 2015		Apr. 30, 2014		Apr. 30, 2015		Apr. 30, 2014
Consolidated Statements of Income [Abstract]
Revenues	$ 383,930		$ 403,761		$ 1,190,981		$ 1,230,855
Costs and expenses:
Direct cost of revenues (exclusive of depreciation and amortization)	316,508		332,376		989,052		1,017,954
Selling, general and administrative (i)	53,792	[1]	55,548	[1]	168,184	[1]	170,588	[1]
Depreciation and amortization	4,617		4,153		13,462		12,108
Research and development			2,514		1,656		7,387
Severance	6,226				8,126
Total costs and expenses	381,143		394,591		1,180,480		1,208,037
Gain on sale of interest in Fabrix Systems Ltd.	1,235				76,864
Other operating (losses) gains, net	(1,552)				(1,552)		1,209
Income from operations	2,470		9,170		85,813		24,027
Interest expense, net	(54)		(135)		(184)		(55)
Other (expense) income, net	(1,352)		159		937		(3,455)
Income before income taxes	1,064		9,194		86,566		20,517
Benefit from (provision for) income taxes	59		(3,595)		(2,332)		(7,895)
Net income	1,123		5,599		84,234		12,622
Net income attributable to noncontrolling interests	(558)		(582)		(1,003)		(1,548)
Net income attributable to IDT Corporation	565		5,017		83,231		11,074
Earnings per share attributable to IDT Corporation common stockholders:
Basic	$ 0.02		$ 0.22		$ 3.64		$ 0.51
Diluted	$ 0.02		$ 0.22		$ 3.58		$ 0.48
Weighted-average number of shares used in calculation of earnings per share:
Basic	23,034		22,680		22,867		21,763
Diluted	23,468		23,023		23,259		22,893
Dividends declared per common share	$ 0.18		$ 0.17		$ 1.85		$ 0.34
(i) Stock-based compensation included in selling, general and administrative expenses	$ 992		$ 793		$ 4,012		$ 4,920

[1] Stock-based compensation included in selling, general and administrative expenses