Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Consolidated Statements of Income [Abstract]
Revenues	$ 355,154	$ 383,930	$ 1,128,186	$ 1,190,981
Costs and expenses:
Direct cost of revenues (exclusive of depreciation and amortization)	293,220	316,508	937,455	989,052
Selling, general and administrative (i)	51,594	53,792	155,738	168,184
Depreciation and amortization	$ 5,518	$ 4,617	$ 15,543	13,462
Research and development				1,656
Severance	$ 232	$ 6,226	$ 232	8,126
Total costs and expenses	$ 350,564	381,143	1,108,968	1,180,480
Other operating losses		(1,552)	(326)	(1,552)
Gain on sale of interest in Fabrix Systems Ltd.	$ 1,086	1,235	1,086	76,864
Income from operations	5,676	2,470	19,978	85,813
Interest income (expense), net	244	(54)	936	(184)
Other income (expense), net	120	(1,352)	(723)	937
Income before income taxes	6,040	1,064	20,191	86,566
(Provision for) benefit from income taxes	(1,339)	59	(6,250)	(2,332)
Net income	4,701	1,123	13,941	84,234
Net income attributable to noncontrolling interests	(464)	(558)	(1,445)	(1,003)
Net income attributable to IDT Corporation	$ 4,237	$ 565	$ 12,496	$ 83,231
Earnings per share attributable to IDT Corporation common stockholders:
Basic	$ 0.19	$ 0.02	$ 0.55	$ 3.64
Diluted	$ 0.19	$ 0.02	$ 0.55	$ 3.58
Weighted-average number of shares used in calculation of earnings per share:
Basic	22,635	23,034	22,790	22,867
Diluted	22,680	23,468	22,816	23,259
Dividends declared per common share	$ 0.19	$ 0.18	$ 0.56	$ 1.85
(i) Stock-based compensation included in selling, general and administrative expenses	$ 673	$ 992	$ 2,317	$ 4,012