Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Income Statement [Abstract]
Revenues	$ 406,423	$ 411,456	$ 827,093	$ 811,573
Costs and expenses:
Direct cost of revenues (exclusive of depreciation and amortization)	335,258	344,486	685,577	679,737
Selling, general and administrative (i)	57,285	55,631	115,040	108,946
Depreciation and amortization	4,059	3,865	7,955	7,000
Research and development	2,597	1,819	4,873	3,201
Total costs and expenses	399,199	405,801	813,445	798,884
Other operating gains (loss), net	350		1,209	(350)
Income from operations	7,574	5,655	14,857	12,339
Interest income (expense), net	105	(457)	80	(352)
Other (expense) income, net	(3,065)	1,815	(3,614)	2,700
Income from continuing operations before income taxes	4,614	7,013	11,323	14,687
Provision for benefit from income taxes	(1,641)	(3,105)	(4,300)	(5,159)
Income from continuing operations	2,973	3,908	7,023	9,528
Loss from discontinued operations, net of tax		(413)		(1,865)
Net income	2,973	3,495	7,023	7,663
Net income attributable to noncontrolling interests	(438)	(542)	(965)	(1,096)
Net income attributable to IDT Corporation	2,535	2,953	6,058	6,567
Amounts attributable to IDT Corporation common stockholders:
Income from continuing operations	2,535	3,284	6,058	8,351
Loss from discontinued operations		(331)		(1,784)
Net income	2,535	2,953	6,058	6,567
Basic:
Income from continuing operations	$ 0.12	$ 0.16	$ 0.28	$ 0.40
Loss from discontinued operations		$ (0.02)		$ (0.08)
Net income	$ 0.12	$ 0.14	$ 0.28	$ 0.32
Weighted-average number of shares used in calculation of basic earnings per share	21,572	20,829	21,305	20,818
Diluted:
Income from continuing operations	$ 0.11	$ 0.15	$ 0.27	$ 0.38
Loss from discontinued operations		$ (0.02)		$ (0.08)
Net income	$ 0.11	$ 0.13	$ 0.27	$ 0.30
Weighted-average number of shares used in calculation of diluted earnings per share	22,743	22,089	22,827	22,087
Dividends declared per common share	$ 0.17		$ 0.17	$ 0.75
(i) Stock-based compensation included in selling, general and administrative expenses	$ 1,632	$ 1,806	$ 4,127	$ 2,818