Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Consolidated Statements of Income [Abstract]
Revenues	$ 382,454	$ 394,173	$ 773,032	$ 807,051
Costs and expenses:
Direct cost of revenues (exclusive of depreciation and amortization)	319,724	328,737	644,235	672,544
Selling, general and administrative (i)	51,054	57,394	104,143	114,392
Depreciation and amortization	$ 4,973	$ 4,440	$ 10,025	8,845
Research and development				1,656
Severance		$ 351		1,899
Total costs and expenses	$ 375,751	$ 390,922	$ 758,403	$ 799,336
Loss on disposal of property, plant and equipment	$ (326)		$ (326)
Gain on sale of interest in Fabrix Systems Ltd.		$ 484		$ 75,629
Income from operations	$ 6,377	3,735	$ 14,303	83,344
Interest income (expense), net	534	(40)	692	(131)
Other (expense) income, net	(234)	967	(844)	2,290
Income before income taxes	6,677	4,662	14,151	85,503
Provision for income taxes	(2,014)	(1,905)	(4,911)	(2,392)
Net income	4,663	2,757	9,240	83,111
Net income attributable to noncontrolling interests	(598)	(247)	(981)	(445)
Net income attributable to IDT Corporation	$ 4,065	$ 2,510	$ 8,259	$ 82,666
Earnings per share attributable to IDT Corporation common stockholders:
Basic	$ 0.18	$ 0.11	$ 0.36	$ 3.63
Diluted	$ 0.18	$ 0.11	$ 0.36	$ 3.57
Weighted-average number of shares used in calculation of earnings per share:
Basic	22,799	22,818	22,867	22,783
Diluted	22,799	23,225	22,884	23,155
Dividends declared per common share	$ 0.19	$ 0.82	$ 0.37	$ 1.67
(i) Stock-based compensation included in selling, general and administrative expenses	$ 873	$ 2,172	$ 1,644	$ 3,020