Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Consolidated Statements of Income [Abstract]
REVENUES	$ 1,496,261	$ 1,596,777	$ 1,651,541
COSTS AND EXPENSES:
Direct cost of revenues (exclusive of depreciation and amortization)	1,246,594	1,328,363	1,367,266
Selling, general and administrative (i)	204,655	222,239	228,934
Depreciation and amortization	20,535	18,418	16,318
Research and development		1,656	10,018
Severance	6,510	8,363
TOTAL COSTS AND EXPENSES	1,478,294	1,579,039	1,622,536
Gain on sale of member interest in Visa Europe Ltd.	7,476
Gain on sale of interest in Fabrix Systems, Ltd.	1,086	76,864
Other operating (losses) gains, net	(326)	(1,552)	835
Income from operations	26,203	93,050	29,840
Interest income (expense), net	1,216	(159)	(148)
Other income (expense), net	2,049	(688)	(4,700)
Income before income taxes	29,468	92,203	24,992
Provision for income taxes	(4,110)	(6,088)	(3,982)
NET INCOME	25,358	86,115	21,010
Net income attributable to noncontrolling interests	(1,844)	(1,625)	(2,226)
NET INCOME ATTRIBUTABLE TO IDT CORPORATION	$ 23,514	$ 84,490	$ 18,784
Earnings per share attributable to IDT Corporation common stockholders:
Basic	$ 1.03	$ 3.69	$ 0.85
Diluted	$ 1.03	$ 3.63	$ 0.82
Weighted-average number of shares used in calculation of earnings per share:
Basic	22,765	22,903	22,009
Diluted	22,815	23,247	22,937
(i) Stock-based compensation included in selling, general and administrative expenses	$ 2,680	$ 5,185	$ 5,382