IDT (IDT) 10-K 14 Oct 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 31, 2014	Jan. 31, 2014	Oct. 06, 2014	Oct. 06, 2014
			Class B Common Stock [Member]	Class A Common Stock [Member]
Document Information [Line Items]	'	'	'	'
Entity Registrant Name	'IDT CORP	'	'	'
Entity Central Index Key	'0001005731	'	'	'
Amendment Flag	'false	'	'	'
Current Fiscal Year End Date	'--07-31	'	'	'
Document Type	'10-K	'	'	'
Document Period End Date	31-Jul-14	'	'	'
Document Fiscal Period Focus	'FY	'	'	'
Document Fiscal Year Focus	'2014	'	'	'
Trading Symbol	'IDT	'	'	'
Entity Well Known Seasoned Issuer	'No	'	'	'
Entity Voluntary Filers	'No	'	'	'
Entity Current Reporting Status	'Yes	'	'	'
Entity Filer Category	'Accelerated Filer	'	'	'
Entity Public Float	'	$304	'	'
Entity Common Stock Shares Outstanding	'	'	21,663,733	1,574,326

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
CURRENT ASSETS:	'	'
Cash and cash equivalents	$153,823	$151,600
Restricted cash and cash equivalents-short-term	65,706	34,988
Marketable securities	12,873	9,684
Trade accounts receivable, net of allowance for doubtful accounts of $11,507 and $13,079 at July 31, 2014 and 2013, respectively	69,330	65,078
Prepaid expenses	21,799	19,175
Deferred income tax assets, net-current portion	2,953	1,689
Other current assets	12,381	12,730
TOTAL CURRENT ASSETS	338,865	294,944
Property, plant and equipment, net	81,760	80,742
Goodwill	14,830	14,807
Other intangibles, net	1,742	1,390
Investments	10,008	9,605
Restricted cash and cash equivalents-long-term	2,763	2,767
Deferred income tax assets, net-long-term portion	16,248	20,000
Other assets	14,715	11,152
TOTAL ASSETS	480,931	435,407
CURRENT LIABILITIES:	'	'
Revolving credit loan payable	13,000	21,062
Trade accounts payable	42,135	39,323
Accrued expenses	142,528	145,432
Deferred revenue	101,165	91,227
Customer deposits	62,685	28,663
Income taxes payable	732	761
Dividends payable	'	1,837
Notes payable-current portion	271	535
Other current liabilities	5,468	4,829
TOTAL CURRENT LIABILITIES	367,984	333,669
Notes payable-long-term portion	6,353	6,624
Other liabilities	5,430	5,978
TOTAL LIABILITIES	379,767	346,271
Commitments and contingencies	'	'
IDT Corporation stockholders' equity:	'	'
Preferred stock, $.01 par value; authorized shares-10,000; no shares issued	'	'
Additional paid-in capital	392,858	388,533
Treasury stock, at cost, consisting of 1,698 and 1,698 shares of Class A common stock and 2,934 and 2,878 shares of Class B common stock at July 31, 2014 and 2013, respectively	-99,841	-98,836
Accumulated other comprehensive income	3,668	2,341
Accumulated deficit	-196,725	-203,711
Total IDT Corporation stockholders' equity	100,239	88,603
Noncontrolling interests	925	533
TOTAL EQUITY	101,164	89,136
TOTAL LIABILITIES AND EQUITY	480,931	435,407
Class A Common Stock [Member]	'	'
IDT Corporation stockholders' equity:	'	'
Common stock, value	33	33
Class B Common Stock [Member]	'	'
IDT Corporation stockholders' equity:	'	'
Common stock, value	$246	$243

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Allowance for doubtful accounts	$11,507	$13,079
Preferred stock, par value	$0.01	$0.01
Preferred stock, Authorized shares	10,000	10,000
Preferred stock, shares issued	'	'
Class A Common Stock [Member]	'	'
Common stock, Par value	$0.01	$0.01
Common stock, shares authorized	35,000	35,000
Common stock, shares issued	3,272	3,272
Common stock, shares outstanding	1,574	1,574
Treasury stock, Common stock shares	1,698	1,698
Class B Common Stock [Member]	'	'
Common stock, Par value	$0.01	$0.01
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	24,587	24,275
Common stock, shares outstanding	21,653	21,397
Treasury stock, Common stock shares	2,934	2,878

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Statement [Abstract]	'	'	'
REVENUES	$1,651,541	$1,620,617	$1,506,283
COSTS AND EXPENSES:	'	'	'
Direct cost of revenues (exclusive of depreciation and amortization)	1,367,266	1,355,573	1,269,386
Selling, general and administrative (i)	228,934	218,469	206,906
Depreciation and amortization	16,318	14,910	16,648
Research and development	10,018	7,166	4,569
Impairment of building and improvements	'	4,359	'
TOTAL COSTS AND EXPENSES	1,622,536	1,600,477	1,497,509
Other operating gains (losses), net	835	9,251	-15,870
Income (loss) from operations	29,840	29,391	-7,096
Interest expense, net	-148	-824	-2,985
Other (expense) income, net	-4,700	5,383	-1,767
Income (loss) from continuing operations before income taxes	24,992	33,950	-11,848
(Provision for) benefit from income taxes	-3,982	-15,872	42,782
Income from continuing operations	21,010	18,078	30,934
Discontinued operations, net of tax:	'	'	'
(Loss) income from discontinued operations	'	-4,634	5,851
Income on sale of discontinued operations	'	'	2,000
Total discontinued operations	'	-4,634	7,851
NET INCOME	21,010	13,444	38,785
Net income attributable to noncontrolling interests	-2,226	-1,837	-137
NET INCOME ATTRIBUTABLE TO IDT CORPORATION	18,784	11,607	38,648
Amounts attributable to IDT Corporation common stockholders:	'	'	'
Income from continuing operations	18,784	16,048	29,901
(Loss) income from discontinued operations	'	-4,441	8,747
NET INCOME ATTRIBUTABLE TO IDT CORPORATION	18,784	11,607	38,648
Basic:	'	'	'
Income from continuing operations	$0.85	$0.85	$1.45
(Loss) income from discontinued operations	'	($0.21)	$0.42
Net income	$0.85	$0.85	$1.87
Weighted-average number of shares used in calculation of basic earnings per share	22,009	20,876	20,717
Diluted:	'	'	'
Income from continuing operations	$0.82	$0.82	$1.36
(Loss) income from discontinued operations	'	($0.20)	$0.39
Net income	$0.82	$0.82	$1.75
Weighted-average number of shares used in calculation of diluted earnings per share	22,937	22,315	22,060
(i) Stock-based compensation included in selling, general and administrative expenses	$5,382	$5,875	$3,325

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'
Net income	$21,010	$13,444	$38,785
Other comprehensive income (loss):	'	'	'
Change in unrealized (loss) gain on available-for-sale securities	-8	-1	4
Foreign currency translation adjustments	1,335	2,092	-2,272
Other comprehensive income (loss)	1,327	2,091	-2,268
COMPREHENSIVE INCOME	22,337	15,535	36,517
Comprehensive income attributable to noncontrolling interests	-2,226	-1,789	-256
COMPREHENSIVE INCOME ATTRIBUTABLE TO IDT CORPORATION	$20,111	$13,746	$36,261

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Noncontrolling Interests [Member]	Receivable for Issuance of Equity [Member]	IDT Corp [Member]	IDT Corp [Member]	IDT Corp [Member]	IDT Corp [Member]	IDT Corp [Member]	IDT Corp [Member]	IDT Corp [Member]
In Thousands				Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Common Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member]
BALANCE at Jul. 31, 2011	$203,790	($4,305)	($1,000)	$520,732	($94,941)	$3,027	($219,992)	'	$33	$236
BALANCE, SHARES at Jul. 31, 2011	'	'	'	'	'	'	'	'	3,272	23,586
Dividends declared	-15,014	'	'	'	'	'	-15,014	'	'	'
Restricted Class B common stock purchased from employee	-210	'	'	'	-210	'	'	'	'	'
Repurchases of Class B common stock through repurchase program	-2,606	'	'	'	-2,606	'	'	'	'	'
Stock-based compensation	3,605	'	'	3,605	'	'	'	'	'	'
Restricted stock issued to employees and directors	'	'	'	-4	'	'	'	'	'	4
Restricted stock issued to employees and directors, Shares	'	'	'	'	'	'	'	'	'	433
Stock issued for matching contributions to the 401(k) Plan	911	'	'	910	'	'	'	'	'	1
Stock issued for matching contributions to the 401(k) Plan, shares	92,843	'	'	'	'	'	'	'	'	93
Sale of stock of subsidiary	133	211	'	-78	'	'	'	'	'	'
Distributions to noncontrolling interests	-1,580	-1,580	'	'	'	'	'	'	'	'
Other	225	225	'	'	'	'	'	'	'	'
Genie/Straight Path Spin-Off	-123,046	5,688	1,000	-129,296	'	-438	'	'	'	'
Other comprehensive income (loss)	-2,268	119	'	'	'	-2,387	'	'	'	'
Net income for the year ended July	38,785	137	'	'	'	'	38,648	'	'	'
BALANCE at Jul. 31, 2012	102,725	495	'	395,869	-97,757	202	-196,358	'	33	241
BALANCE, SHARES at Jul. 31, 2012	'	'	'	'	'	'	'	'	3,272	24,112
Dividends declared	-18,960	'	'	'	'	'	-18,960	'	'	'
Restricted Class B common stock purchased from employee	-301	'	'	'	-301	'	'	'	'	'
Repurchases of Class B common stock through repurchase program	-778	'	'	'	-778	'	'	'	'	'
Exercise of stock options	921	'	'	920	'	'	'	'	'	1
Exercise of stock options, Shares	'	'	'	'	'	'	'	'	'	62
Stock-based compensation	6,616	204	'	6,412	'	'	'	'	'	'
Restricted stock issued to employees and directors	'	'	'	-1	'	'	'	'	'	1
Restricted stock issued to employees and directors, Shares	'	'	'	'	'	'	'	'	'	49
Stock issued for matching contributions to the 401(k) Plan	932	'	'	932	'	'	'	'	'	'
Stock issued for matching contributions to the 401(k) Plan, shares	51,861	'	'	'	'	'	'	'	'	52
Purchases of stock of subsidiary	1,804	9	'	1,795	'	'	'	'	'	'
Sale of stock of subsidiary	145	203	'	-58	'	'	'	'	'	'
Distributions to noncontrolling interests	-2,245	-2,245	'	'	'	'	'	'	'	'
Exercise of stock options in subsidiary	9	6	'	3	'	'	'	'	'	'
Genie/Straight Path Spin-Off	-13,659	90	'	-13,749	'	'	'	'	'	'
Other comprehensive income (loss)	2,091	-48	'	'	'	2,139	'	'	'	'
Net income for the year ended July	13,444	1,837	'	'	'	'	11,607	'	'	'
BALANCE at Jul. 31, 2013	89,136	533	'	388,533	-98,836	2,341	-203,711	'	33	243
BALANCE, SHARES at Jul. 31, 2013	'	'	'	'	'	'	'	0	3,272	24,275
Dividends declared	-11,798	'	'	'	'	'	-11,798	'	'	'
Restricted Class B common stock purchased from employee	-1,005	'	'	'	-1,005	'	'	'	'	'
Exercise of stock options	609	3	'	606	'	'	'	'	'	'
Exercise of stock options, Shares	'	'	'	'	'	'	'	'	'	46
Stock-based compensation	5,362	30	'	5,332	'	'	'	'	'	'
Restricted stock issued to employees and directors	'	'	'	-2	'	'	'	'	'	2
Restricted stock issued to employees and directors, Shares	'	'	'	'	'	'	'	'	'	194
Stock issued for matching contributions to the 401(k) Plan	1,168	'	'	1,167	'	'	'	'	'	1
Stock issued for matching contributions to the 401(k) Plan, shares	72,281	'	'	'	'	'	'	'	'	72
Purchases of stock of subsidiary	-1,133	21	'	-1,154	'	'	'	'	'	'
Distributions to noncontrolling interests	-1,888	-1,888	'	'	'	'	'	'	'	'
Genie/Straight Path Spin-Off	-1,624	'	'	-1,624	'	'	'	'	'	'
Other comprehensive income (loss)	1,327	'	'	'	'	1,327	'	'	'	'
Net income for the year ended July	21,010	2,226	'	'	'	'	18,784	'	'	'
BALANCE at Jul. 31, 2014	$101,164	$925	'	$392,858	($99,841)	$3,668	($196,725)	'	$33	$246
BALANCE, SHARES at Jul. 31, 2014	'	'	'	'	'	'	'	'	3,272	24,587

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Parenthetical) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Statement Of Stockholders Equity [Abstract]	'	'	'
Dividends declared, per share	$0.51	$0.83	$0.66

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
OPERATING ACTIVITIES	'	'	'
Net income	$21,010	$13,444	$38,785
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Net loss (income) from discontinued operations	'	4,634	-7,851
Depreciation and amortization	16,318	14,910	16,648
Impairment of building and improvements	'	4,359	'
Deferred income taxes	2,487	15,198	-37,925
Provision for doubtful accounts receivable	500	2,743	2,098
Net realized gains from investments	'	-586	'
Gain on proceeds from insurance	-571	'	'
Interest in the equity of investments	-1,282	-1,968	-1,157
Stock-based compensation	5,382	5,875	3,325
Change in assets and liabilities:	'	'	'
Restricted cash and cash equivalents	-25,292	-23,006	-7,733
Trade accounts receivable	-1,363	17,606	8,728
Prepaid expenses, other current assets and other assets	-4,628	2,890	-2,100
Trade accounts payable, accrued expenses, other current liabilities and other liabilities	-5,914	-22,578	10,703
Customer deposits	30,186	17,998	9,057
Income taxes payable	-29	-576	-4,721
Deferred revenue	8,917	6,253	6,666
Net cash provided by operating activities	45,721	57,196	34,523
INVESTING ACTIVITIES	'	'	'
Capital expenditures	-17,021	-14,537	-10,830
Deposit on purchase of leasehold interest in building	'	-950	'
Collection of notes receivable, net	'	750	'
Cash used for acquisition and purchase of investments	-175	-1,219	'
Proceeds from sales and redemptions of investments	1,038	114	3,169
Purchases of other intangibles	-250	-93	'
Proceeds from sale of building	250	'	'
Proceeds from insurance	571	'	'
Purchases of marketable securities	-20,658	-11,414	'
Proceeds from maturities and sales of marketable securities	17,323	1,712	'
Proceeds from maturities of certificates of deposit	'	'	3,300
Net cash used in investing activities	-18,922	-25,637	-4,361
FINANCING ACTIVITIES	'	'	'
Cash of subsidiaries deconsolidated as a result of spin-offs	'	-15,000	-104,243
Dividends paid	-13,635	-17,123	-15,014
Distributions to noncontrolling interests	-1,888	-2,245	-1,580
Purchases of stock of subsidiary	-1,133	-1,804	'
Proceeds from sales of stock and exercise of stock options of subsidiary	'	154	133
Proceeds from exercise of stock options	609	921	'
Repayments of capital lease obligations	'	'	-1,781
Proceeds from revolving credit loan payable	56,000	21,062	'
Repayments of revolving credit loan payable and other borrowings	-64,318	-21,304	-332
Repurchases of Class B common stock	-1,005	-1,079	-2,816
Net cash used in financing activities	-25,370	-36,418	-125,633
DISCONTINUED OPERATIONS	'	'	'
Net cash used in operating activities	'	-2,638	-1,984
Net cash (used in) provided by investing activities	'	-350	4,992
Net cash (used in) provided by discontinued operations	'	-2,988	3,008
Effect of exchange rate changes on cash and cash equivalents	794	1,241	-2,335
Net increase (decrease) in cash and cash equivalents	2,223	-6,606	-94,798
Cash and cash equivalents (including discontinued operations) at beginning of year	151,600	158,206	253,004
Cash and cash equivalents (including discontinued operations) at end of year	153,823	151,600	158,206
Less cash and cash equivalents of discontinued operations at end of year	'	'	2,598
Cash and cash equivalents (excluding discontinued operations) at end of year	153,823	151,600	155,608
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION	'	'	'
Cash payments made for interest	743	1,286	3,621
Cash payments made for income taxes	1,115	483	1,049
SUPPLEMENTAL SCHEDULE OF NON-CASH FINANCING AND INVESTING ACTIVITIES	'	'	'
Adjustment to liabilities in connection with the Straight Path Spin-Off	1,624	'	'
Escrow account balances included in other current assets used to reduce notes payable	'	1,976	'
Net liabilities (assets) excluding cash and cash equivalents of subsidiaries deconsolidated as a result of spin-offs	'	$1,341	($18,803)

Description_of_Business_and_Su

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Jul. 31, 2014
Description of Business and Summary of Significant Accounting Policies [Abstract]	'
Description of Business and Summary of Significant Accounting Policies	'
	Note 1—Description of Business and Summary of Significant Accounting Policies
	Description of Business
	IDT Corporation (“IDT” or the “Company”) is a multinational holding company with operations primarily in the telecommunications and payment industries. The Company has three reportable business segments, Telecom Platform Services, Consumer Phone Services and Zedge Holdings, Inc. (“Zedge”). Telecom Platform Services provides retail telecommunications and payment offerings as well as wholesale international long distance traffic termination. Consumer Phone Services provides consumer local and long distance services in certain U.S. states. Telecom Platform Services and Consumer Phone Services comprise the IDT Telecom division. Zedge owns and operates an online platform for mobile phone consumers interested in obtaining free, high-quality games, apps, and mobile phone customization including ringtones, wallpapers, and notification sounds. Operating segments not reportable individually are included in All Other. All Other includes Fabrix Systems Ltd. (“Fabrix”), a software development company offering a cloud-based scale-out storage and computing platform optimized for big data, virtualization and media storage, processing and delivery. The Company sold Fabrix in October 2014 (see Note 22). All Other also includes the Company’s real estate holdings and other, smaller, businesses.
	On July 31, 2013, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Straight Path Communications Inc. (“Straight Path”), to the Company’s stockholders of record as of the close of business on July 25, 2013 (the “Straight Path Spin-Off”) (see Note 2). On October 28, 2011, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Genie Energy Ltd. (“Genie”), to the Company’s stockholders of record as of the close of business on October 21, 2011 (the “Genie Spin-Off”) (see Note 2). Straight Path and Genie met the criteria to be reported as discontinued operations and accordingly, their assets, liabilities, results of operations and cash flows are classified as discontinued operations for all periods presented.
	Basis of Consolidation and Accounting for Investments
	The method of accounting applied to long-term investments, whether consolidated, equity or cost, involves an evaluation of the significant terms of each investment that explicitly grant or suggest evidence of control or influence over the operations of the investee and also includes the identification of any variable interests in which the Company is the primary beneficiary. The consolidated financial statements include the Company’s controlled subsidiaries. In addition, the Company has not identified any variable interests in which the Company is the primary beneficiary. All significant intercompany accounts and transactions between the consolidated subsidiaries are eliminated.
	Investments in businesses that the Company does not control, but in which the Company has the ability to exercise significant influence over operating and financial matters, are accounted for using the equity method. Investments in which the Company does not have the ability to exercise significant influence over operating and financial matters are accounted for using the cost method. Investments in hedge funds are accounted for using the equity method unless the Company’s interest is so minor that it has virtually no influence over operating and financial policies, in which case these investments are accounted for using the cost method. At July 31, 2014 and 2013, the Company had $9.4 million and $8.1 million, respectively, in investments accounted for using the equity method, and $1.8 million and $1.5 million, respectively, in investments accounted for using the cost method. Equity and cost method investments are included in “Other current assets” or “Investments” in the accompanying consolidated balance sheets. The Company periodically evaluates its equity and cost method investments for impairment due to declines considered to be other than temporary. If the Company determines that a decline in fair value is other than temporary, then a charge to earnings is recorded in “Other (expense) income, net” in the accompanying consolidated statements of income, and a new basis in the investment is established.
	Reclassifications
	Certain prior year amounts were reclassified to conform to the current year’s presentation:
		●	In the consolidated balance sheet, $4.6 million previously included in “Restricted cash and cash equivalents—long-term” at July 31, 2013 was reclassified to “Cash and cash equivalents”;
		●	In the consolidated statements of cash flows, cash used for “Restricted cash and cash equivalents” in the years ended July 31, 2013 and 2012 of $2.1 million and $2.0 million, respectively, was reclassified to “Cash and cash equivalents”; and
		●	In the consolidated statement of cash flows, $8.7 million previously included in “Restricted cash and cash equivalents” at July 31, 2011 was reclassified to “Cash and cash equivalents”.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.
	Revenue Recognition
	Telephone service, which includes domestic and international long distance, local service, and wholesale carrier telephony services is recognized as revenue when services are provided, primarily based on usage and/or the assessment of fees. Revenue from Boss Revolution PIN-less international calling service and from sales of calling cards, net of customer discounts, is deferred until the service or the cards are used or, calling card administrative fees are imposed, thereby reducing the Company’s outstanding obligation to the customer, at which time revenue is recognized. Domestic and international airtime top-up revenue is recognized upon redemption. International airtime top-up enables customers to purchase airtime for a prepaid mobile telephone in another country.
	IDT Telecom enters into reciprocal transactions pursuant to which IDT Telecom is committed to purchase a specific number of minutes to specific destinations at specified rates, and the counterparty is committed to purchase from IDT Telecom a specific number of minutes to specific destinations at specified rates. The number of minutes purchased and sold in a reciprocal transaction is not necessarily equal. The rates in these reciprocal transactions are generally greater than prevailing market rates. In addition, IDT Telecom enters into transactions in which it swaps minutes with another carrier. The Company recognizes revenue and the related direct cost of revenue for these reciprocal and swap transactions based on the fair value of the minutes.
	Zedge revenues from traditional web/mobile web and Android/iOS applications are recognized based on blocks of impressions or ad views. Revenues from mobile games are recognized upon download by the end user.
	Revenue from Fabrix for software licenses and maintenance support was deferred and recognized on a straight-line basis from the date on which delivered orders were accepted by the customer over the period that the support was expected to be provided since sufficient vendor-specific objective evidence of fair value to allocate revenues to the various deliverables did not exist in fiscal 2014, fiscal 2013 or fiscal 2012.
	Direct Cost of Revenues
	Direct cost of revenues for IDT Telecom consists primarily of termination and origination costs, toll-free costs, and network costs—including customer/carrier interconnect charges and leased fiber circuit charges. These costs include an estimate of charges for which invoices have not yet been received, and estimated amounts for pending disputes with other carriers. Subsequent adjustments to these estimates may occur after the invoices are received for the actual costs incurred, but these adjustments generally are not material to the Company’s results of operations. Direct cost of revenues for IDT Telecom also includes the cost of airtime top-up minutes.
	Direct cost of revenues for Zedge consists of ad server costs, web hosting charges, and copyright/infringement prevention costs.
	Direct cost of revenues for Fabrix consisted primarily of customer support expenses.
	Direct cost of revenues excludes depreciation and amortization expense.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents.
	Restricted Cash and Cash Equivalents
	The Company classifies the change in its restricted cash and cash equivalents as an operating activity in the accompanying consolidated statements of cash flows because the restrictions are directly related to the operations of IDT Financial Services, the Company’s Gibraltar-based bank, and IDT Telecom.
	Substantially Restricted Cash and Cash Equivalents
	IDT Payment Services, which provides the Company’s international money transfer services in the United States, and IDT Financial Services set aside certain cash balances in accordance with banking regulations, credit card issuer requirements or license compliance. These balances are included in “Cash and cash equivalents” in the Company’s consolidated balance sheet. The balances are not legally restricted, however the Company treats these balances as substantially restricted and unavailable for other purposes.
	Marketable Securities
	The Company’s investments in marketable securities are classified as “available-for-sale.” Available-for-sale securities are required to be carried at their fair value, with unrealized gains and losses (net of income taxes) that are considered temporary in nature recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. The Company uses the specific identification method in computing the gross realized gains and gross realized losses on the sales of marketable securities. The Company periodically evaluates its investments in marketable securities for impairment due to declines in market value considered to be other than temporary. Such impairment evaluations include, in addition to persistent, declining market prices, general economic and Company-specific evaluations. If the Company determines that a decline in market value is other than temporary, then a charge to operations is recorded in “Other (expense) income, net” in the accompanying consolidated statements of income and a new cost basis in the investment is established.
	Long-Lived Assets
	Equipment, buildings, computer software and furniture and fixtures are recorded at cost and are depreciated on a straight-line basis over their estimated useful lives, which range as follows: equipment—5, 7 or 20 years; buildings—40 years; computer software—2, 3 or 5 years and furniture and fixtures—5, 7 or 10 years. Leasehold improvements are recorded at cost and are depreciated on a straight-line basis over the term of their lease or their estimated useful lives, whichever is shorter.
	Costs associated with obtaining the right to use trademark and patents owned by third parties are capitalized and amortized on a straight-line basis over the term of the relevant trademark and patent licenses. The fair value of technology and domain names, customer lists, and trademark acquired in a business combination accounted for under the purchase method are amortized over their estimated useful lives as follows: technology and domain names are amortized on a straight-line basis over the 3 year estimated useful lives; customer lists are amortized ratably over the approximately 15 year period of expected cash flows; and trademark is amortized on a straight-line basis over the 5 year period of expected cash flows.
	The Company tests the recoverability of its long-lived assets with finite useful lives whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company tests for recoverability based on the projected undiscounted cash flows to be derived from such asset. If the projected undiscounted future cash flows are less than the carrying value of the asset, the Company will record an impairment loss, if any, based on the difference between the estimated fair value and the carrying value of the asset. The Company generally measures fair value by considering sale prices for similar assets or by discounting estimated future cash flows from such asset using an appropriate discount rate. Cash flow projections and fair value estimates require significant estimates and assumptions by management. Should the estimates and assumptions prove to be incorrect, the Company may be required to record impairments in future periods and such impairments could be material.
	Goodwill
	Goodwill is the excess of the acquisition cost of businesses over the fair value of the identifiable net assets acquired. Goodwill and other indefinite lived intangible assets are not amortized. These assets are reviewed annually (or more frequently under various conditions) for impairment using a fair value approach. The goodwill impairment assessment involves estimating the fair value of the reporting unit and comparing it to its carrying amount, which is known as Step 1. If the carrying value of the reporting unit exceeds its estimated fair value, Step 2 is performed to determine if an impairment of goodwill is required. The fair value of the reporting units is estimated using discounted cash flow methodologies, as well as considering third party market value indicators. Goodwill impairment is measured by the excess of the carrying amount of the reporting unit’s goodwill over its implied fair value. Calculating the fair value of the reporting units, and allocating the estimated fair value to all of the tangible assets, intangible assets and liabilities, requires significant estimates and assumptions by management. Should the estimates and assumptions regarding the fair value of the reporting units prove to be incorrect, the Company may be required to record impairments to its goodwill in future periods and such impairments could be material.
	The Company has the option to perform a qualitative assessment to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. However, the Company may elect to perform the two-step quantitative goodwill impairment test even if no indications of a potential impairment exist.
	For its reporting unit with zero or negative carrying amount, the Company performs Step 2 of the goodwill impairment test if it is more likely than not that a goodwill impairment exists. In determining whether it is more likely than not that goodwill impairment exists, the Company considers whether there are any adverse qualitative factors indicating that impairment may exist.
	Advertising Expense
	Cost of advertising is charged to selling, general and administrative expenses in the period in which it is incurred. In fiscal 2014, fiscal 2013 and fiscal 2012, advertising expense was $17.2 million, $13.1 million and $17.0 million, respectively.
	Research and Development Costs
	Costs for research and development are charged to expense as incurred. Research and development costs were primarily incurred by Fabrix.
	Capitalized Internal Use Software Costs
	The Company capitalizes the cost of internal-use software that has a useful life in excess of one year. These costs consist of payments made to third parties and the salaries of employees working on such software development. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they allow the software to perform a task it previously did not perform. Software maintenance and training costs are expensed in the period in which they are incurred. Capitalized internal use software costs are amortized on a straight-line basis over their estimated useful lives. Amortization expense related to such capitalized software in fiscal 2014, fiscal 2013 and fiscal 2012 was $7.6 million, $6.3 million and $5.8 million, respectively. Unamortized capitalized internal use software costs at July 31, 2014 and 2013 were $13.2 million and $10.2 million, respectively.
	Repairs and Maintenance
	The Company charges the cost of repairs and maintenance, including the cost of replacing minor items not constituting substantial betterment, to selling, general and administrative expenses as these costs are incurred.
	Foreign Currency Translation
	Assets and liabilities of foreign subsidiaries denominated in foreign currencies are translated to U.S. Dollars at end-of-period rates of exchange, and their monthly results of operations are translated to U.S. Dollars at the average rates of exchange for that month. Gains or losses resulting from such foreign currency translations are recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are reported in “Other (expense) income, net” in the accompanying consolidated statements of income.
	Income Taxes
	The Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the period in which related temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in its assessment of a valuation allowance. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date of such change.
	The Company uses a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. The Company determines whether it is more-likely-than-not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. Tax positions that meet the more-likely-than-not recognition threshold are measured to determine the amount of tax benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement. Differences between tax positions taken in a tax return and amounts recognized in the financial statements will generally result in one or more of the following: an increase in a liability for income taxes payable, a reduction of an income tax refund receivable, a reduction in a deferred tax asset, or an increase in a deferred tax liability.
	The Company classifies interest and penalties on income taxes as a component of income tax expense.
	Contingencies
	The Company accrues for loss contingencies when both (a) information available prior to issuance of the financial statements indicates that it is probable that a liability had been incurred at the date of the financial statements and (b) the amount of loss can reasonably be estimated. When the Company accrues for loss contingencies and the reasonable estimate of the loss is within a range, the Company records its best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company accrues the minimum amount in the range. The Company discloses an estimated possible loss or a range of loss when it is at least reasonably possible that a loss may have been incurred.
	Earnings Per Share
	Basic earnings per share is computed by dividing net income attributable to all classes of common stockholders of the Company by the weighted average number of shares of all classes of common stock outstanding during the applicable period. Diluted earnings per share is determined in the same manner as basic earnings per share, except that the number of shares is increased to include restricted stock still subject to risk of forfeiture and to assume exercise of potentially dilutive stock options using the treasury stock method, unless the effect of such increase is anti-dilutive.
	The weighted-average number of shares used in the calculation of basic and diluted earnings per share attributable to the Company’s common stockholders consists of the following:
	Year ended July 31		2014		2013		2012
	(in thousands)
	Basic weighted-average number of shares			22,009		20,876		20,717
	Effect of dilutive securities:
Stock options			92		9		—
Non-vested restricted Class B common stock			836		1,430		1,343
Diluted weighted-average number of shares			22,937		22,315		22,060
The following outstanding stock options were excluded from the calculation of diluted earnings per share because the exercise price of the stock option was greater than the average market price of the Company’s stock during the period:
Year ended July 31		2014		2013		2012
(in thousands)
Shares excluded from the calculation of diluted earnings per share			70		611		619
Stock-Based Compensation
The Company recognizes compensation expense for all of its grants of stock-based awards based on the estimated fair value on the grant date. Compensation cost for awards is recognized using the straight-line method over the vesting period. Stock-based compensation is included in selling, general and administrative expense.
Taxes Collected from Customers and Remitted to Governmental Authorities
The Company collects taxes from its customers that are remitted to governmental authorities in the normal course of its operations. These taxes, which are imposed on or are concurrent with specific revenue-producing transactions, include Universal Service Fund (“USF”) charges, sales, use, value added and certain excise taxes. The Company currently records USF charges that are billed to customers on a gross basis in its results of operations, and records other taxes on a net basis. USF charges in the amount of $0.6 million, $0.8 million and $1.1 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively, were recorded on a gross basis and included in “Revenues” and “Direct cost of revenues” in the accompanying consolidated statements of income.
Vulnerability Due to Certain Concentrations
Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash, cash equivalents, restricted cash and cash equivalents, marketable securities, investments in hedge funds and trade accounts receivable. The Company holds cash and cash equivalents at several major financial institutions, which often exceed FDIC insurance limits. Historically, the Company has not experienced any losses due to such concentration of credit risk. The Company’s temporary cash investments policy is to limit the dollar amount of investments with any one financial institution and monitor the credit ratings of those institutions. While the Company may be exposed to credit losses due to the nonperformance of the holders of its deposits, the Company does not expect the settlement of these transactions to have a material effect on its results of operations, cash flows or financial condition.
Concentration of credit risk with respect to trade accounts receivable is limited due to the large number of customers in various geographic regions and industry segments comprising the Company’s customer base. No single customer accounted for more than 10% of consolidated revenues in fiscal 2014, fiscal 2013 or fiscal 2012. However, the Company’s five largest customers collectively accounted for 12.0%, 10.0% and 8.1% of its consolidated revenues from continuing operations in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. The Company’s customers with the five largest receivables balances collectively accounted for 22.1% and 16.6% of the consolidated gross trade accounts receivable at July 31, 2014 and 2013, respectively. This concentration of customers increases the Company’s risk associated with nonpayment by those customers. In an effort to reduce such risk, the Company performs ongoing credit evaluations of its significant retail, wholesale and cable telephony customers. In addition, the Company attempts to mitigate the credit risk related to specific wholesale termination customers by also buying services from the customer, in order to create an opportunity to offset its payables and receivables and reduce its net trade receivable exposure risk. When it is practical to do so, the Company will increase its purchases from wholesale termination customers with receivable balances that exceed the Company’s applicable payables in order to maximize the offset and reduce its credit risk.
Allowance for Doubtful Accounts
The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the accounts receivable balance. The allowance is determined based on known troubled accounts, historical experience and other currently available evidence. Doubtful accounts are written-off upon final determination that the trade accounts will not be collected. The change in the allowance for doubtful accounts is as follows:
Year ended July 31		Balance at		Additions		Deductions(1)			Balance at
(in thousands)		beginning of		charged to					end of year
		year		costs and
				expenses
2014
Reserves deducted from accounts receivable:
Allowance for doubtful accounts		$	13,079	$	500	$	(2,072	)	$	11,507
2013
Reserves deducted from accounts receivable:
Allowance for doubtful accounts		$	13,044	$	2,743	$	(2,708	)	$	13,079
2012
Reserves deducted from accounts receivable:
Allowance for doubtful accounts		$	15,364	$	2,098	$	(4,418	)	$	13,044
-1	Primarily uncollectible accounts written off, net of recoveries.
Fair Value Measurements
Fair value of financial and non-financial assets and liabilities is defined as an exit price, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used to measure fair value, which prioritizes the inputs to valuation techniques used to measure fair value, is as follows:
Level 1 –	quoted prices (unadjusted) in active markets for identical assets or liabilities.
Level 2 –	quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument.
Level 3 –	unobservable inputs based on the Company’s assumptions used to measure assets and liabilities at fair value.
A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the assets and liabilities being measured and their placement within the fair value hierarchy.
Recently Issued Accounting Standard Not Yet Adopted
In May 2014, the Financial Accounting Standards Board and the International Accounting Standards Board jointly issued a comprehensive new revenue recognition standard that will supersede most of the current revenue recognition guidance under U.S. GAAP and International Financial Reporting Standards (“IFRS”). The goals of the revenue recognition project were to clarify and converge the revenue recognition principles under U.S. GAAP and IFRS and to develop guidance that would streamline and enhance revenue recognition requirements. The Company will adopt this standard on August 1, 2017. Entities have the option of using either a full retrospective or modified retrospective approach for the adoption of the standard. The Company is evaluating the impact that the standard will have on its consolidated financial statements.
Recently Adopted Accounting Standard
In April 2014, an accounting standard update was issued that changed the criteria for reporting discontinued operations and enhanced convergence of U.S. GAAP and IFRS reporting requirements for discontinued operations. The amendments in the update raise the threshold for a disposal to qualify as a discontinued operation and require new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. Early adoption is permitted but only for disposals (or classifications as held for sale) that have not been reported in previously issued financial statements. The Company adopted this standard update as of August 1, 2014. In accordance with this standard update, the Company does not expect the sale of Fabrix in October 2014 to qualify as a discontinued operation. The Company is unable to determine at this time whether the adoption of this standard update will have further effect on its financial position, results of operations or cash flows in the future for other disposals.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Jul. 31, 2014
Discontinued Operations [Abstract]	'
Discontinued Operations	'
	Note 2—Discontinued Operations
	Straight Path Communications, Inc.
	On July 31, 2013, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Straight Path Communications Inc., to the Company’s stockholders of record as of the close of business on July 25, 2013. At the time of the Straight Path Spin-Off, Straight Path owned 100% of Straight Path Spectrum, Inc., which holds, leases and markets fixed wireless spectrum licenses, and 84.5% of Straight Path IP Group, Inc., which holds intellectual property primarily related to communications over the Internet and the licensing and other businesses related to this intellectual property. As of July 31, 2013, each of the Company’s stockholders received one share of Straight Path Class A common stock for every two shares of the Company’s Class A common stock and one share of Straight Path Class B common stock for every two shares of the Company’s Class B common stock held of record as of the close of business on July 25, 2013. Straight Path and its subsidiaries met the criteria to be reported as discontinued operations and accordingly, their assets, liabilities, results of operations and cash flows are classified as discontinued operations for all periods presented.
	The Company believes that the Straight Path Spin-Off was tax-free for the Company and the Company’s stockholders for U.S. federal income tax purposes under Section 355 of the Internal Revenue Code of 1986 (the “Code”). The Company received an opinion from Pryor Cashman LLP on the requirements for a tax-free distribution. Specifically, the opinion concluded that the distribution (i) should satisfy the business purpose requirement of the Code for a tax-free distribution, (ii) should not be viewed as being used principally as a device for the distribution of earnings and profits of the distributing corporation or the controlled corporation or both, and (iii) should not be viewed as part of a plan (or series of related transactions) pursuant to which one or more persons will acquire directly or indirectly stock representing a 50 percent or greater interest in the distributing corporation or controlled corporation within the meaning of the relevant section of the Code.
	In connection with the Straight Path Spin-Off, the Company funded Straight Path with a total of $15.0 million in aggregate cash and cash equivalents.
	Genie Energy Ltd.
	On October 28, 2011, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Genie Energy Ltd., to the Company’s stockholders of record as of the close of business on October 21, 2011. At the time of the Genie Spin-Off, Genie owned 99.3% of Genie Energy International Corporation, which owned 100% of IDT Energy and 92% of Genie Oil and Gas, Inc. As of October 28, 2011, each of the Company’s stockholders received one share of Genie Class A common stock for every share of the Company’s Class A common stock and one share of Genie Class B common stock for every share of the Company’s Class B common stock held of record as of the close of business on October 21, 2011. Genie and subsidiaries met the criteria to be reported as discontinued operations and accordingly, their assets, liabilities, results of operations and cash flows are classified as discontinued operations for all periods presented.
	The Company received a ruling from the Internal Revenue Service (“IRS”) substantially to the effect that, for U.S. federal income tax purposes, the distribution of shares of Genie common stock will qualify as tax-free for Genie, the Company and the Company’s stockholders under Section 355 of the Code. In addition to obtaining the IRS ruling, the Company received an opinion from PricewaterhouseCoopers LLP on the three requirements for a tax-free distribution that are not addressed in the IRS ruling. Specifically, the opinion concludes that the distribution (i) should satisfy the business purpose requirement of the Code for a tax-free distribution, (ii) should not be viewed as being used principally as a device for the distribution of earnings and profits of the distributing corporation or the controlled corporation or both, and (iii) should not be viewed as part of a plan (or series of related transactions) pursuant to which one or more persons will acquire directly or indirectly stock representing a 50 percent or greater interest in the distributing corporation or controlled corporation within the meaning of the relevant section of the Code.
	In connection with the Genie Spin-Off, the Company funded Genie with a total of $106.0 million in aggregate cash and cash equivalents, including restricted cash.
	IDT Entertainment
	In connection with the sale of IDT Entertainment to Liberty Media Corporation in the first quarter of fiscal 2007, the Company was eligible to receive additional consideration from Liberty Media based upon any appreciation in the value of IDT Entertainment over the five-year period that ended in August 2011, however, the Company may have been required to pay Liberty Media up to $3.5 million if the value of IDT Entertainment did not exceed a certain amount by August 2011. In September 2011, the Company and Liberty Media executed an agreement to settle and resolve all claims related to the additional consideration and certain other disputes and claims. Liberty Media paid the Company $2.0 million in September 2011 in consideration for the settlement and related releases, which is included in “Income on sale of discontinued operations” in fiscal 2012 in the accompanying consolidated statement of income.
	Summary Financial Data of Discontinued Operations
	Revenues, income before income taxes and net income (loss) of Straight Path and Genie, which are included in discontinued operations, were as follows:
	Year ended July 31	2014		2013			2012
	(in thousands)
	REVENUES
	Straight Path	$	—	$	1,130		$	553
	Genie		—		—			45,796
	TOTAL	$	—	$	1,130		$	46,349
	(LOSS) INCOME BEFORE INCOME TAXES
	Straight Path	$	—	$	(4,621	)	$	4,862
	Genie		—		—			2,609
	TOTAL	$	—	$	(4,621	)	$	7,471
	NET (LOSS) INCOME
	Straight Path	$	—	$	(4,634	)	$	4,836
	Genie		—		—			1,015
	TOTAL	$	—	$	(4,634	)	$	5,851

Marketable_Securities

Marketable Securities	12 Months Ended
	Jul. 31, 2014
Marketable Securities [Abstract]	'
Marketable Securities	'
	Note 3—Marketable Securities
	The following is a summary of marketable securities:
	(in thousands)	Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	31-Jul-14
	Available-for-sale securities:
	Certificates of deposit*	$	10,375	$	—	$	—		$	10,375
	Equity securities		31		—		(9	)		22
	Municipal bonds		2,475		1		—			2,476
	TOTAL	$	12,881	$	1	$	(9	)	$	12,873
	31-Jul-13
	Available-for-sale securities:
	Certificates of deposit*	$	8,786	$	—	$	—		$	8,786
	Municipal bonds		898		—		—			898
	TOTAL	$	9,684	$	—	$	—		$	9,684
	*Each of the Company’s certificates of deposit has a CUSIP, was purchased in the secondary market through a broker and may be sold in the secondary market.
	Proceeds from maturities and sales of available-for-sale securities were $17.3 million, $1.7 million and nil in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. There were no realized gains or losses from sales of available-for-sale securities in fiscal 2014, fiscal 2013 and fiscal 2012. In fiscal 2014, the Company recorded a loss of $0.1 million for the other than temporary decline in market value of its equity securities.
	The contractual maturities of the Company’s available-for-sale securities at July 31, 2014 were as follows:
	(in thousands)	Fair Value
	Within one year	$	12,851
	After one year through five years		—
	After five years through ten years		—
	After ten years		—
	TOTAL	$	12,851

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Jul. 31, 2014
Fair Value Measurements [Abstract]	'
Fair Value Measurements	'
	Note 4—Fair Value Measurements
	The following table presents the balance of assets measured at fair value on a recurring basis:
	(in thousands)	Level 1		Level 2		Level 3		Total
	31-Jul-14
	Available-for-sale securities	$	—	$	12,873	$	—	$	12,873
	31-Jul-13
	Available-for-sale securities	$	—	$	9,684	$	—	$	9,684
	At July 31, 2014 and 2013, the Company did not have any liabilities measured at fair value on a recurring basis. At July 31, 2014 and 2013, the Company had $9.5 million and $8.3 million, respectively, in investments in hedge funds, of which $0.1 million and $0.1 million, respectively, were included in “Other current assets” and $9.4 million and $8.2 million, respectively, were included in “Investments” in the accompanying consolidated balance sheets. The Company’s investments in hedge funds are accounted for using the equity method or the cost method, therefore investments in hedge funds are not measured at fair value.
	Fair Value of Other Financial Instruments
	The estimated fair value of the Company’s other financial instruments was determined using available market information or other appropriate valuation methodologies. However, considerable judgment is required in interpreting these data to develop estimates of fair value. Consequently, the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange.
	Cash and cash equivalents, restricted cash and cash equivalents—short-term, other current assets, revolving credit loan payable, customer deposits, dividend payable, notes payable—current portion and other current liabilities. At July 31, 2014 and 2013, the carrying amount of these assets and liabilities approximated fair value because of the short period of time to maturity. The fair value estimates for cash, cash equivalents and restricted cash and cash equivalents—short-term were classified as Level 1 and other current assets, revolving credit loan payable, customer deposits, dividend payable, notes payable—current portion and other current liabilities were classified as Level 2 of the fair value hierarchy.
	Restricted cash and cash equivalents—long-term. At July 31, 2014 and 2013, the carrying amount of restricted cash and cash equivalents—long-term approximated fair value. The fair value was estimated based on the anticipated cash flows once the restrictions are removed, which was classified as Level 2 of the fair value hierarchy.
	Notes payable—long-term portion and other liabilities. At July 31, 2014 and 2013, the carrying amount of these liabilities approximated fair value. The fair values were estimated based on the Company’s assumptions, which was classified as Level 3 of the fair value hierarchy.
	The Company’s investments at July 31, 2014 and 2013 included investments in the equity of certain privately held entities and other investments that are accounted for at cost. It is not practicable to estimate the fair value of these investments because of the lack of a quoted market price for the shares of these entities, and the inability to estimate their fair value without incurring excessive cost. The carrying value of these investments was $1.8 million and $1.5 million at July 31, 2014 and 2013, respectively, which the Company believes was not impaired.

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Jul. 31, 2014
Property Plant And Equipment [Abstract]	'
Property, Plant and Equipment	'
	Note 5—Property, Plant and Equipment
	Property, plant and equipment consist of the following:
	July 31	2014			2013
	(in thousands)
	Equipment	$	438,899		$	436,127
	Land and buildings		53,895			51,294
	Computer software		116,775			105,449
	Leasehold improvements		42,190			45,141
	Furniture and fixtures		6,249			6,187
			658,008			644,198
	Less accumulated depreciation and amortization		(576,248	)		(563,456	)
	Property, plant and equipment, net	$	81,760		$	80,742
	In fiscal 2013, the Company recorded an impairment charge of $4.4 million for the building and improvements that it owns at 520 Broad Street, Newark, New Jersey. The following facts and circumstances indicated that the fair value of the building and improvements may be less than their carrying value at that time: (1) the building was not occupied and, at the time, the Company did not expect to occupy it, (2) economic uncertainty and sluggish leasing activity stalled a recovery of the real estate market in Newark, (3) there were no potential tenants, (4) no sale of the building had been completed and there were no other likely buyers, (5) the building would be expensive to redevelop and (6) the building was expected to remain vacant for the foreseeable future. The Company determined the fair value of the building and improvements based on estimates of an owner/user’s market rental rate net of costs of improvements and tenant work as well as the estimated value to an investor/developer after deducting costs of improvements and costs to achieve full occupancy. This fair value measurement was classified as Level 2 of the fair value hierarchy.
	In fiscal 2014, the Company began renovations of the first four floors of its 520 Broad Street building in order to move its personnel and offices currently located at 550 Broad Street, Newark, New Jersey to 520 Broad Street. The move is expected to occur during fiscal 2015. The Company also plans to lease or sell the office space on the other floors, although there are no potential tenants or buyers at this time. At both July 31, 2014 and 2013, the carrying value of the land, building and improvements at 520 Broad Street after the impairment charge was $37.7 million.
	Depreciation and amortization expense of property, plant and equipment was $15.7 million, $14.3 million and $15.9 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively.

Goodwill_and_Other_Intangibles

Goodwill and Other Intangibles	12 Months Ended
	Jul. 31, 2014
Goodwill and Other Intangibles [Abstract]	'
Goodwill and Other Intangibles	'
	Note 6—Goodwill and Other Intangibles
	The table below reconciles the change in the carrying amount of goodwill by operating segment for the period from July 31, 2012 to July 31, 2014:
	(in thousands)	Telecom Platform		Zedge		Total
		Services
	Balance as of July 31, 2012	$	11,407	$	3,207	$	14,614
	Foreign currency translation adjustments		193		—		193
	Balance as of July 31, 2013		11,600		3,207		14,807
	Foreign currency translation adjustments		23		—		23
	Balance as of July 31, 2014	$	11,623	$	3,207	$	14,830
	The table below presents information on the Company’s other intangible assets:
	(in thousands)	Weighted		Gross		Accumulated			Net
		Average		Carrying		Amortization			Balance
		Amortization		Amount
		Period
	31-Jul-14
	Amortized intangible assets:
	Trademarks and patents		4.7 years	$	670	$	(335	)	$	335
	Technology and domain names		3.0 years		708		(68	)		640
	Customer lists		6.5 years		3,154		(2,387	)		767
	TOTAL		5.7 years	$	4,532	$	(2,790	)	$	1,742
	31-Jul-13
	Amortized intangible assets:
	Trademarks and patents		4.7 years	$	2,119	$	(1,715	)	$	404
	Customer lists		6.8 years		3,154		(2,168	)		986
	TOTAL		6.0 years	$	5,273	$	(3,883	)	$	1,390
	Amortization expense of intangible assets was $0.6 million, $0.6 million and $0.7 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. The Company estimates that amortization expense of intangible assets with finite lives will be $0.5 million, $0.4 million, $0.3 million, $0.1 million and $0.1 million in fiscal 2015, fiscal 2016, fiscal 2017, fiscal 2018 and fiscal 2019, respectively.

Other_Operating_Gains_Losses_N

Other Operating Gains (Losses), Net	12 Months Ended
	Jul. 31, 2014
Other (Expense) Income, Net [Abstract]	'
Other Operating Gains (Losses), Net	'
	Note 7—Other Operating Gains (Losses), Net
	The following table summarizes the other operating gains (losses), net by business segment:
	Year ended July 31		2014			2013		2012
	(in thousands)
	Telecom Platform Services—gains (losses) related to legal matters, net		$	650		$	9,251	$	(6,698	)
	Telecom Platform Services—loss on settlement of litigation (a)			—			—		(11,022	)
	Telecom Platform Services—gain on settlement of claim (b)			—			—		1,750
	Corporate—loss related to settlement (c)			(79	)		—		—
	Corporate—other			(374	)		—		100
	All Other—gain on insurance claim (d)			571			—		—
	All Other—other			67			—		—
	TOTAL		$	835		$	9,251	$	(15,870	)
	Telecom Platform Services
	(a)	On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. (“T-Mobile”) to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.
	(b)	On January 17, 2012, the Company received $1.8 million from Broadstripe, LLC in settlement of the Company’s claim stemming from Broadstripe, LLC’s rejection of its telephony services agreements with the Company upon the confirmation of Broadstripe, LLC’s bankruptcy plan and closing of its bankruptcy sale.
	Corporate
	(c)	In fiscal 2014, the Company incurred a loss of $0.1 million in connection with the June 2013 settlement of outstanding claims and disputes with the former Chief Executive Officer of Straight Path Spectrum, Inc. and his related parties.
	All Other
	(d)	In fiscal 2014, the Company received proceeds from insurance of $0.6 million related to water damage to portions of the Company’s building and improvements at 520 Broad Street, Newark, New Jersey. The damage occurred in a prior period. The Company recorded a gain of $0.6 million from this insurance claim.

Revolving_Credit_Loan_Payable

Revolving Credit Loan Payable	12 Months Ended
	Jul. 31, 2014
Revolving Credit Loan Payable [Abstract]	'
Revolving Credit Loan Payable	'
	Note 8—Revolving Credit Loan Payable
	The Company’s subsidiary, IDT Telecom, Inc., entered into a credit agreement, dated July 12, 2012, with TD Bank, N.A. for a line of credit facility for up to a maximum principal amount of $25.0 million. IDT Telecom may use the proceeds to finance working capital requirements, acquisitions and for other general corporate purposes. The line of credit facility is secured by primarily all of IDT Telecom’s assets. The principal outstanding bears interest per annum, at the option of IDT Telecom, at either (a) the U.S. Prime Rate less 125 basis points, or (b) the LIBOR rate adjusted by the Regulation D maximum reserve requirement plus 150 basis points. Interest is payable monthly and all outstanding principal and any accrued and unpaid interest is due on the maturity date of January 31, 2015. At July 31, 2014 and 2013, there was $13.0 million and $21.1 million, respectively, outstanding under the facility. The principal outstanding at July 31, 2014 and 2013 incurred interest at a rate of 1.65% and 1.69%, respectively, per annum. In August 2014, the Company repaid the $13.0 million loan payable. The Company intends to continue to borrow under the facility from time to time. IDT Telecom pays a quarterly unused commitment fee of 0.375% per annum on the average daily balance of the unused portion of the $25.0 million commitment. IDT Telecom is required to comply with various affirmative and negative covenants as well as maintain certain financial targets and ratios during the term of the line of credit, including IDT Telecom may not pay any dividend on its capital stock and IDT Telecom’s aggregate loans and advances to affiliates or subsidiaries may not exceed $90.0 million. At July 31, 2014 and 2013, there were no amounts utilized for letters of credit under the line of credit, IDT Telecom was in compliance with all of the covenants, and IDT Telecom’s aggregate loans and advances to affiliates and subsidiaries was $73.7 million and $46.4 million, respectively.

Notes_Payable

Notes Payable	12 Months Ended
	Jul. 31, 2014
Notes Payable [Abstract]	'
Notes Payable	'
	Note 9—Notes Payable
	The Company’s notes payable consist of the following:
	31-Jul		2014			2013
	(in thousands)
	$11.0 million secured term loan due September 2015 (a)		$	6,624		$	6,880
	$1.2 million note due June 2012 (b)			—			279
	Total notes payable			6,624			7,159
	Less current portion			(271	)		(535	)
	Notes payable—long term portion		$	6,353		$	6,624
	The future principal payments for the note payable as of July 31, 2014 are as follows:
	(in thousands)
	Year ending July 31:
	2015		$	271
	2016			6353
	2017			—
	2018			—
	2019			—
	Thereafter			—
	Total notes payable		$	6,624
	(a)	The loan bears interest at the rate of 5.6% per annum and is payable in monthly installments of principal and interest of $0.1 million, with the last installment of $6.4 million payable on September 1, 2015. The loan is secured by a mortgage on a building in Piscataway, New Jersey.
	(b)	On June 24, 2009, the Company issued a promissory note in the principal amount of $1.2 million in connection with the acquisition of the 49% interest in Union Telecard Alliance, LLC that it did not own. The note incurred interest at 0.76% per annum. The principal and interest were payable in thirty six equal, monthly installments that began on July 24, 2009 with the last payment scheduled for June 24, 2012. The Company had not made any payments since November 2011 due to disputes with the seller. In fiscal 2014, in accordance with an arbitration award, the Company paid the remaining principal and accrued interest to the seller.

Accrued_Expenses

Accrued Expenses	12 Months Ended
	Jul. 31, 2014
Accrued Expenses [Abstract]	'
Accrued Expenses	'
	Note 10—Accrued Expenses
	Accrued expenses consist of the following:
	31-Jul	2014		2013
	(in thousands)
	Carrier minutes termination	$	53,280	$	50,687
	Carrier network connectivity, toll-free and 800 services		7,896		11,462
	Regulatory fees and taxes		43,293		38,602
	Legal settlements		1,615		11,784
	Compensation costs		15,612		12,836
	Legal and professional fees		4,708		6,026
	Other		16,124		14,035
	TOTAL	$	142,528	$	145,432

Other_Expense_Income_Net

Other (Expense) Income, Net	12 Months Ended
	Jul. 31, 2014
Other (Expense) Income, Net [Abstract]	'
Other (Expense) Income, Net	'
	Note 11—Other (Expense) Income, Net
	Other (expense) income, net consists of the following:
	Year ended July 31	2014			2013			2012
	(in thousands)
	Foreign currency transaction (losses) gains	$	(5,883	)	$	2,538		$	(2,859	)
	Gain on investments		1,218			2,664			1,172
	Gain on modification and early termination of note payable		—			238			—
	Gain on sales of buildings and other assets		—			11			197
	Other		(35	)		(68	)		(277	)
	TOTAL	$	(4,700	)	$	5,383		$	(1,767	)
	On April 30, 2013, the Company and the holder of the note payable secured by the mortgage on the building located at 520 Broad Street, Newark, New Jersey (the “Lender”) entered into an agreement to settle all disputes between the Company and Lender. In connection with this agreement, on May 1, 2013, the Company paid the Lender $21.1 million and the Lender released the Company from the note and discharged the mortgage. In fiscal 2013, the Company recognized a gain of $0.2 million on the modification and early termination of the note payable.

Income_Taxes

Income Taxes	12 Months Ended
	Jul. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Note 12—Income Taxes
	The components of income (loss) from continuing operations before income taxes are as follows:
	Year ended July 31	2014			2013			2012
	(in thousands)
	Domestic	$	21,624		$	44,355		$	9,573
	Foreign		3,368			(10,405	)		(21,421	)
	INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	$	24,992		$	33,950		$	(11,848	)
	Significant components of the Company’s deferred income tax assets consist of the following:
	31-Jul	2014			2013
	(in thousands)
	Deferred income tax assets:
	Bad debt reserve	$	2,188		$	2,812
	Accrued expenses		2,937			7,096
	Stock options and restricted stock		2,131			2,786
	Charitable contributions		1,230			2,415
	Impairment		25,745			25,566
	Depreciation		7,566			989
	Unrealized gain		163			507
	Net operating loss		126,093			144,001
	Credits		3,123			2,845
	Total deferred income tax assets		171,176			189,017
	Valuation allowance		(151,975	)		(167,328	)
	DEFERRED INCOME TAX ASSETS, NET	$	19,201		$	21,689
	The (provision for) benefit from income taxes consists of the following:
	Year ended July 31	2014			2013			2012
	(in thousands)
	Current:
	Federal	$	(279	)	$	671		$	1,652
	State and local		—			148			2,503
	Foreign		(1,177	)		(1,431	)		1,741
			(1,456	)		(612	)		5,896
	Deferred:
	Federal		(6,461	)		(14,181	)		36,166
	State and local		(175	)		(1,079	)		764
	Foreign		4,110			—			(44	)
			(2,526	)		(15,260	)		36,886
	(PROVISION FOR) BENEFIT FROM INCOME TAXES	$	(3,982	)	$	(15,872	)	$	42,782
	The benefit from income taxes in fiscal 2012 was primarily due to the $36.9 million reversal of a portion of the Company’s valuation allowance in the United States. In fiscal 2012, the Company determined that it was more likely than not that a portion of its deferred income tax assets would be realized, therefore the valuation allowance related to those assets was reversed. The Company based its determination on a projection of future U.S. income and took into consideration the historical U.S. performance and decided a partial release of the U.S. valuation that relates to the core businesses was warranted in that period. Assumptions regarding future taxable income require significant analysis and judgment. This analysis included financial forecasts based on historical performance of the core business and continuance of doing business in a jurisdiction in which losses were incurred. Based on its projections, the Company expected that it would generate future taxable income over the next five years in the U.S. jurisdiction and will begin utilizing its net operating loss carryover through this period. Accordingly, the Company concluded that a portion of its U.S. jurisdiction core business assets did not require a full valuation allowance. In fiscal 2013 and fiscal 2014, the Company updated the analysis and concluded that the valuation allowance related to its core U.S. business should be maintained at the current level and will be reevaluated as warranted. In addition, in fiscal 2014, the Company determined that its valuation allowance on the losses of IDT Global, a U.K. subsidiary, were no longer required due to an internal reorganization that generated income and a projection that the income would continue. The Company recorded a benefit from income taxes of $4.1 million from the full recognition of the IDT Global deferred tax assets.
	The Company did not release any of the valuation allowances that related to its former Straight Path Spectrum business since it was not part of the main tax consolidated group and the portion of the Net2Phone acquired net operating loss that is subject to Internal Revenue Code Section 382 limitations (see below). The Company did not release any of the valuation allowances related to its foreign operations in fiscal 2013 or fiscal 2012 as it was not more likely than not that the assets will be utilized based upon the earnings history and the profitability projections. Both the loss and valuation allowance that were part of the Straight Path Spin-Off are reflected as reductions in the total amounts in the deferred income tax assets, net table above.
	The differences between income taxes expected at the U.S. federal statutory income tax rate and income taxes provided are as follows:
	Year ended July 31	2014			2013			2012
	(in thousands)
	U.S. federal income tax at statutory rate	$	(8,747	)	$	(11,883	)	$	4,147
	Valuation allowance		4,110			—			41,961
	Foreign tax rate differential		961			(5,073	)		(5,800	)
	Nondeductible expenses		761			714			(26	)
	Other		7			50			—
	Prior year tax (expense) benefit		(960	)		921			2,500
	State and local income tax, net of federal benefit		(114	)		(601	)		—
	(PROVISION FOR) BENEFIT FROM INCOME TAXES	$	(3,982	)	$	(15,872	)	$	42,782
	At July 31, 2014, the Company had federal and state net operating loss carryforwards of approximately $168 million. This carry-forward loss is available to offset future U.S. federal and state taxable income. The net operating loss carryforwards will start to expire in fiscal 2014, with fiscal 2009’s loss expiring in fiscal 2030. The Company has foreign net operating losses of approximately $200 million, of which approximately $143 million does not expire and approximately $57 million expires in two to ten years. These foreign net operating losses are available to offset future taxable income in the countries in which the losses were incurred. The Company’s subsidiary, Net2Phone, which provides voice over Internet protocol communications services, has additional federal net operating losses of approximately $84 million, which will expire through fiscal 2027. With the reacquisition of Net2Phone by the Company in March 2006, its losses were limited under Internal Revenue Code Section 382 to approximately $7 million per year. The net operating losses do not include any excess benefits related to stock options or restricted stock.
	The Company has not recorded U.S. income tax expense for foreign earnings, as such earnings are permanently reinvested outside the United States. The cumulative undistributed foreign earnings are included in accumulated deficit in the Company’s consolidated balance sheets, and consisted of approximately $270 million at July 31, 2014. Upon distribution of these foreign earnings to the Company’s domestic entities, the Company may be subject to U.S. income taxes and withholding of foreign taxes, however, it is not practicable to determine the amount, if any, which would be paid.
	The change in the valuation allowance is as follows:
	Year ended July 31	Balance at			Additions			Deductions			Balance at
	(in thousands)	beginning of			charged to						end of year
		year			costs and
					expenses
	2014
	Reserves deducted from deferred income taxes, net:
	Valuation allowance	$	167,328		$	—		$	(15,353	)	$	151,975
	2013
	Reserves deducted from deferred income taxes, net:
	Valuation allowance	$	204,977		$	462		$	(38,111	)	$	167,328
2012
Reserves deducted from deferred income taxes, net:
Valuation allowance	$	206,669		$	41,925		$	(43,617	)	$	204,977
The table below summarizes the change in the balance of unrecognized income tax benefits:
Year ended July 31	2014			2013			2012
(in thousands)
Balance at beginning of year	$	356		$	—		$	3,754
Additions based on tax positions related to the current year		—			—			—
Additions for tax positions of prior years		—			356			—
Reductions for tax positions of prior years		—			—			—
Settlements		(356	)		—			(3,754	)
Lapses of statutes of limitations		—			—			—
Balance at end of year	$	—		$	356		$	—
Settlements of $3.8 million in fiscal 2012 were primarily due to an agreement on certain state tax positions and the related payment of the taxes due, as well as the settlement of a foreign audit.
In fiscal 2014, fiscal 2013 and fiscal 2012, the Company did not record any interest and penalties on income taxes. As of July 31, 2014 and 2013, there was no accrued interest included in current income taxes payable.
The Company currently remains subject to examinations of its tax returns as follows: U.S. federal tax returns for fiscal 2011 to fiscal 2014, state and local tax returns generally for fiscal 2010 to fiscal 2014 and foreign tax returns generally for fiscal 2010 to fiscal 2014.

Equity

Equity	12 Months Ended
	Jul. 31, 2014
Equity [Abstract]	'
Equity	'
	Note 13—Equity
	Class A Common Stock and Class B Common Stock
	The rights of holders of Class A common stock and Class B common stock are identical except for certain voting and conversion rights and restrictions on transferability. The holders of Class A common stock and Class B common stock receive identical dividends per share when and if declared by the Company’s Board of Directors. In addition, the holders of Class A common stock and Class B common stock have identical and equal priority rights per share in liquidation. The Class A common stock and Class B common stock do not have any other contractual participation rights. The holders of Class A common stock are entitled to three votes per share and the holders of Class B common stock are entitled to one-tenth of a vote per share. Each share of Class A common stock may be converted into one share of Class B common stock, at any time, at the option of the holder. Shares of Class A common stock are subject to certain limitations on transferability that do not apply to shares of Class B common stock.
	Dividend Payments
	In July 2013, the Company’s Board of Directors declared a special dividend of $0.08 per share to holders of the Company’s Class A common stock and Class B common stock. At July 31, 2013, dividends payable were $1.8 million.
	In fiscal 2014, the Company paid aggregate cash dividends of $0.59 per share on its Class A common stock and Class B common stock, or $13.6 million in total. In fiscal 2013, the Company paid aggregate cash dividends of $0.75 per share on its Class A common stock and Class B common stock, or $17.1 million in total. In fiscal 2012, the Company paid aggregate cash dividends of $0.66 per share on its Class A common stock and Class B common stock, or $15.0 million in total.
	On October 3, 2014, the Company paid a dividend of $0.17 per share for the fourth quarter of fiscal 2014 to holders of record of the Company’s Class A common stock and Class B common stock as of the close of business on September 29, 2014.
	Stock Repurchases
	The Company has a stock repurchase program for the repurchase of up to an aggregate of 8.3 million shares of the Company’s Class B common stock. There were no repurchases under the program in fiscal 2014. In fiscal 2013, the Company repurchased 77,843 shares of Class B common stock for an aggregate purchase price of $0.8 million. In fiscal 2012, the Company repurchased 0.3 million shares of Class B common stock for an aggregate purchase price of $2.6 million. As of July 31, 2014, 5.1 million shares remained available for repurchase under the stock repurchase program.
	Purchases of Stock of Subsidiary
	In August 2013, Fabrix and another wholly-owned subsidiary of the Company purchased shares of Fabrix for aggregate cash of $1.1 million. The shares were purchased from holders of noncontrolling interests in Fabrix representing 2.8% of the equity in Fabrix, which increased the Company’s ownership in Fabrix to 88.4%.
	In December 2012, a wholly-owned subsidiary of the Company purchased Fabrix shares for cash of $1.8 million. The shares were purchased from holders of noncontrolling interests in Fabrix representing 4.5% of the equity in Fabrix.
	Sales of Stock of Subsidiaries
	On November 21, 2012, the Company’s subsidiary, Zedge, sold shares to Shaman II, L.P. for cash of $0.1 million, which increased Shaman II, L.P.’s ownership in Zedge to 11.17% from 11.1%. On November 15, 2011, Zedge sold shares to Shaman II, L.P. for cash of $0.1 million, which increased Shaman II, L.P.’s ownership in Zedge to 11.1% from 11%. One of the limited partners in Shaman II, L.P. is a former employee of the Company.
	Adjustment to Liabilities in connection with the Straight Path Spin-Off
	The Company’s Separation and Distribution Agreement with Straight Path includes, among other things, that the Company is obligated to reimburse Straight Path for the payment of any liabilities of Straight Path arising or related to the period prior to the Straight Path Spin-Off (see Note 18). In fiscal 2014, the Company increased its estimated liability for this obligation by $1.9 million, of which $1.6 million was recorded as a reduction of additional paid-in capital.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Jul. 31, 2014
Stock-Based Compensation [Abstract]	'
Stock-Based Compensation	'
	Note 14—Stock-Based Compensation
	Stock-Based Compensation Plans
	The Company’s 2005 Stock Option and Incentive Plan, as amended and restated, is intended to provide incentives to executives, employees, directors and consultants of the Company. Incentives available under the 2005 Stock Option and Incentive Plan may include stock options, stock appreciation rights, limited rights, deferred stock units, and restricted stock. In December 2011, the Company’s stockholders approved an amendment to the 2005 Stock Option and Incentive Plan to increase the number of shares of the Company’s Class B common stock available for the grant of awards by an additional 1.1 million shares. At July 31, 2014, the Company had 5.3 million shares of Class B common stock reserved for award under its 2005 Stock Option and Incentive Plan and 0.3 million shares were available for future grants.
	In September 2014, the Company’s Board of Directors adopted the 2014 Stock Option and Incentive Plan, which is subject to ratification by the Company’s stockholders. It is expected that the 2014 Stock Option and Incentive Plan will become effective on January 1, 2015. Shares available for future grants under the 2005 Stock Option and Incentive Plan will no longer be available once the 2014 Stock Option and Incentive Plan is effective. The 2014 Stock Option and Incentive Plan is intended to provide incentives to officers, employees, directors and consultants of the Company, including stock options, stock appreciation rights, limited rights, deferred stock units, and restricted stock. There will be 0.5 million shares of the Company’s Class B common stock authorized for award under the 2014 Stock Option and Incentive Plan.
	No income tax benefits were recognized in the consolidated statements of income for stock-based compensation arrangements during fiscal 2014, fiscal 2013 or fiscal 2012. In fiscal 2014 and fiscal 2013, there was no tax benefit resulting from tax deductions in excess of the compensation cost recognized for the Company’s stock-based compensation. In fiscal 2012, the Company did not recognize the tax benefits because the deferred tax benefit was fully reserved for due to the uncertainty of future taxable income.
	Stock Options
	Option awards are generally granted with an exercise price equal to the market price of the Company’s stock on the date of grant. Option awards generally vest on a graded basis over three years of service and have ten-year contractual terms. The fair value of stock options was estimated on the date of the grant using a Black-Scholes valuation model and the assumptions in the following table. No option awards were granted in fiscal 2014 and fiscal 2013. Expected volatility is based on historical volatility of the Company’s Class B common stock and other factors. The Company uses historical data on exercise of stock options, post vesting forfeitures and other factors to estimate the expected term of the stock-based payments granted. The risk free rate is based on the U.S. Treasury yield curve in effect at the time of grant.
	ASSUMPTIONS
	Year ended July 31	2012
	Average risk-free interest rate		1.46	%
	Expected dividend yield		4.6	%
	Expected volatility		66.8	%
	Expected term		6.6 years
	A summary of stock option activity for the Company is as follows:
		Number of			Weighted-		Weighted-		Aggregate
		Options			Average		Average		Intrinsic Value
		(in thousands)			Exercise		Remaining		(in thousands)
					Price		Contractual
							Term
							(in years)
	Outstanding at July 31, 2013		642		$	14.22
	Granted		—			—
	Exercised		(29	)		13.45
	Cancelled / Forfeited		(2	)		21.38
	OUTSTANDING AT JULY 31, 2014		611		$	14.24		6.6	$	1,285
	EXERCISABLE AT JULY 31, 2014		438		$	15.63		5.2	$	444
	The weighted-average grant date fair value of options granted by the Company during fiscal 2012 was $4.97. The total intrinsic value of options exercised during fiscal 2014 and fiscal 2013 was $0.2 million and $0.2 million, respectively. As of July 31, 2014, there was $1.4 million of total unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over a weighted-average period of 2.2 years.
	In August 2013, in connection with the Straight Path Spin-Off, the exercise price of each outstanding option to purchase the Company’s Class B common stock was reduced by 15.29% of the exercise price based on the change in the trading price of the Company’s Class B common stock following the Straight Path Spin-Off. Further, each holder of options to purchase the Company’s Class B common stock shared ratably in a pool of options to purchase 32,155 shares of Straight Path Class B common stock. The Company accounted for the August 2013 reduction in the exercise price of the Company’s outstanding stock options and the grant of new options in Straight Path as a modification. The Company determined that there was no incremental value from the modification, and therefore, the Company was not required to record a stock-based compensation charge.
	On March 26, 2012, the Compensation Committee of the Company’s Board of Directors approved an extension of the expiration dates of all outstanding stock options held by current employees and consultants of the Company. The expiration date of every stock option was extended for three years from the prior scheduled expiration date. The Compensation Committee also approved the issuance of new options in replacement of certain stock options that had recently expired, setting the expiration date of the newly issued stock options three years from the date of the new grant. All newly issued options were fully vested and the exercise prices were unchanged. This extension or replacement applied to options to purchase an aggregate of 0.6 million shares of the Company’s Class B common stock. The Company recorded stock-based compensation expense of $0.3 million in March 2012 for the modification or issuance of the options based on the estimated fair values on March 26, 2012.
	On November 22, 2011, there were fully vested outstanding options to purchase 0.5 million shares of the Company’s Class B common stock, with various exercise prices and expiration dates. The exercise prices of all of such options were above the market price for the Company’s Class B common stock on such date. On November 22, 2011, in connection with the Genie Spin-Off, the exercise price of each outstanding option to purchase the Company’s Class B common stock was reduced by 43.8% of the exercise price based on the change in the trading price of the Company’s Class B common stock following the Genie Spin-Off. Further, each option holder shared ratably in a pool of options to purchase 50,000 shares of Genie Class B common stock. The Company accounted for the November 2011 reduction in the exercise price of the Company’s outstanding stock options and the grant of new options in Genie as a modification. The Company determined that there was no incremental value from the modification, therefore, the Company did not record a stock-based compensation charge.
	Restricted Stock
	The fair value of restricted shares of the Company’s Class B common stock is determined based on the closing price of the Company’s Class B common stock on the grant date. Share awards generally vest on a graded basis over three years of service.
	A summary of the status of the Company’s grants of restricted shares of Class B common stock is presented below:
	(in thousands)	Number of			Weighted-
		Non-vested			Average Grant-
		Shares			Date Fair
					Value
	Non-vested shares at July 31, 2013		2,013		$	6.11
	Granted		183			19.71
	Vested		(1,649	)		5.29
	Forfeited		(7	)		10.17
	NON-VESTED SHARES AT JULY 31, 2014		540		$	13
	As of July 31, 2014, there was $3.5 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements, which is expected to be recognized over a weighted-average period of 0.9 years. The total grant date fair value of shares vested in fiscal 2014, fiscal 2013 and fiscal 2012 was $8.7 million, $3.5 million and $5.7 million, respectively.
	Straight Path IP Group Stock
	On September 24, 2012, the Company’s Board of Directors approved a grant of 10% of the equity of the Company’s former subsidiary, Straight Path IP Group, to Mr. Howard S. Jonas, the Company’s Chairman of the Board and former Chief Executive Officer. These Straight Path IP Group shares vested immediately. The Company recorded stock-based compensation expense of $0.7 million in fiscal 2013 for the grant of these shares, based on the estimated fair value of the shares on the grant date.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	12 Months Ended
	Jul. 31, 2014
Accumulated Other Comprehensive Income Loss [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	Note 15—Accumulated Other Comprehensive Income
	The accumulated balances for each classification of other comprehensive income (loss) were as follows:
	(in thousands)	Unrealized			Foreign			Accumulated
		gain (loss) on			currency			other
		available-for-			translation			comprehensive
		sale securities						income (loss)
	Balance at July 31, 2011	$	(4	)	$	3,031		$	3,027
	Genie Spin-Off		—			(438	)		(438	)
	Other comprehensive loss attributable to IDT Corporation		4			(2,391	)		(2,387	)
	Balance at July 31, 2012		—			202			202
	Other comprehensive income attributable to IDT Corporation		—			2,139			2,139
	Balance at July 31, 2013		—			2,341			2,341
	Other comprehensive income attributable to IDT Corporation		(8	)		1,335			1,327
	BALANCE AT JULY 31, 2014	$	(8	)	$	3,676		$	3,668

Legal_Proceedings

Legal Proceedings	12 Months Ended
	Jul. 31, 2014
Legal Proceedings and Commitments And Contingencies Disclosure [Abstract]	'
Legal Proceedings	'
	Note 16—Legal Proceedings
	On October 17, 2013, the Company and Alexsam, Inc. (“Alexsam”) entered into a confidential Settlement Agreement pursuant to which the parties agreed to fully compromise, settle and release any and all claims and counterclaims related to Alexsam’s action in the United States District Court, Eastern District of Texas alleging infringement of two patents related to the activation of phone and gift cards (incorporating bank identification numbers approved by the American Banking Association for use in a banking network) over a point-of-sale terminal. In a judgment issued in August 2011, Alexsam was awarded an aggregate of $10.1 million including damages and interest. The Settlement Agreement included a prospective royalty free license. On November 4, 2013, the Company paid Alexsam the settlement amount.
	In connection with an arbitration hearing with Aerotel, Ltd. (“Aerotel”) that was held in June 2012, on March 15, 2013, the arbitration panel issued its Final Award, and determined that Aerotel sustained damages, inclusive of interest at 9% per annum through March 15, 2013, in the total amount of approximately $5.4 million. On April 8, 2013, Aerotel filed a Petition for Judgment Vacating the Arbitration Awards in the United States District Court, Southern District of New York along with a Motion supporting its Petition to Vacate the Arbitration Awards. After briefing, on July 18, 2013, the Court confirmed the award, and as a result, in July 2013, the Company paid Aerotel $5.4 million, including interest. On August 14, 2013, Aerotel filed a Notice of Appeal with the Court of Appeals, 2nd Circuit. After briefing, oral argument was held on May 21, 2014 and on June 3, 2014, the Court of Appeals affirmed the decision of the District Court.
	The Company’s subsidiary Prepaid Cards BVBA was the exclusive licensee of a patent related to a method and process used in prepaid calling cards that was invented by Shmuel Fromer, which has now expired. The Company had been attempting to enforce this patent in Germany, and had succeeded, prevailing in infringement cases against certain calling card providers, including Lycatel (Ireland) Limited and Lycatel Services Limited, and Mox Telecom AG. On February 21, 2012, a nullity hearing (effectively judging the validity of the patent) with respect to the patent, took place before the German Federal Court of Justice in Karlsruhe, between Lycatel Services Limited as claimant, Mox Telecom AG as intervenor on the side of claimant, and Mr. Fromer, as defendant. During this hearing, the court nullified claims 1, 2, 3, 5 and 6 of the patent. The Court also ordered the defendant to pay costs and fees in respect of all of the nullity proceedings involving Lycatel and Mox. Except for the amount of fees and costs which may be claimed against the Company in connection with the infringement proceedings, which are based on applicable statutes (for which the Company has accrued $1.1 million at July 31, 2014), the outcome of this matter is uncertain, and, as such, the Company is not able to make an assessment of the final result and its impact on the Company. The Company paid the court fees in connection with the infringement proceedings, and in March 2014, paid Lycatel for its own fees and costs. Mox’s costs and fees in connection with the infringement proceedings have not been determined. Upon enforcement of the judgments in these cases, the Company was required to transfer security deposits to the Court. While the security deposit for the Lycatel case was subsequently released to the Company, at this time the relevant courts have declined to release the security deposit for the Mox case. Mox recently filed for bankruptcy. The Company is examining its options with respect to the release of this deposit.
	On May 5, 2004, the Company filed a complaint in the Supreme Court of the State of New York, County of New York, seeking injunctive relief and damages against Tyco Group, S.A.R.L., Tyco Telecommunications (US) Inc. (f/k/a TyCom (US) Inc.), Tyco International, Ltd., Tyco International (US) Inc., and TyCom Ltd. (collectively “Tyco”). The Company alleged that Tyco breached a settlement agreement that it had entered into with the Company to resolve certain disputes and civil actions among the parties. The Company alleged that Tyco did not provide the Company, as required under the settlement agreement, free of charge and for the Company’s exclusive use, a 15-year indefeasible right to use four Wavelengths in Ring Configuration (as defined in the settlement agreement) (“Wavelengths”) on a global undersea fiber optic network that Tyco was deploying at that time. In June 2004, Tyco asserted several counterclaims against the Company, alleging that the Company breached the settlement agreement and is liable for damages for allegedly refusing to accept Tyco’s offer regarding the Wavelengths referenced in the settlement agreement and for making a public statement that Tyco failed to provide the Company with the use of its Wavelengths. On August 19, 2008, the Appellate Division of the State of New York, First Department, granted summary judgment in favor of Tyco dismissing the complaint and remanded the matter to the Supreme Court for further proceedings. On October 22, 2009, the New York Court of Appeals issued an Order denying the Company’s appeal and affirming the Appellate Division’s order. On or about November 17, 2009, the Company demanded that Tyco comply with its obligations under the settlement agreement. After further discussions and meetings between the parties regarding Tyco’s obligations under the settlement agreement, including its obligation to provide the use of the Wavelengths for fifteen years in a manner fully consistent with that described in the settlement agreement, the Company filed a complaint on November 24, 2010 in the Supreme Court of the State of New York, County of New York, against Tyco based upon the failure to comply with the obligations under the settlement agreement, to negotiate the terms of an indefeasible right to use the Wavelengths in good faith, and to provide the Company with the Wavelengths. The complaint alleges causes of action for breach of contract and breach of duty to negotiate in good faith. On January 6, 2011, Tyco filed a motion to dismiss the complaint, which was granted. On July 22, 2011, the Company filed a notice of appeal. After briefing was completed, oral argument was held on April 2, 2012. On December 27, 2012, the Appellate Division issued an opinion and order reversing the order of the Supreme Court that granted Tyco’s motion to dismiss the Company’s complaint. On April 30, 2013, Tyco filed a motion for reargument or, in the alternative, leave to appeal to the Court of Appeals, which the Company opposed. On February 8, 2013, Tyco filed an answer with a counterclaim. On May 21, 2013, the Appellate Division denied Tyco’s request for reargument but granted its request for leave to appeal to the Court of Appeals. On July 30, 2013, Tyco filed its opening brief, the Company filed its response brief on September 16, 2013, and Tyco filed its reply on October 11, 2013. Oral argument was held on April 29, 2014. On June 5, 2014, the Court issued its decision, and reversed the order of the Appellate Division, and ordered that the order of the Supreme Court should be reinstated. On July 7, 2014, the Company filed a motion for reargument with the Court of Appeals, which Tyco opposed. On September 11, 2014, the Court denied the Company’s motion. The Company is evaluating its options going forward.
	In addition to the foregoing, the Company is subject to other legal proceedings that have arisen in the ordinary course of business and have not been finally adjudicated. Although there can be no assurance in this regard, none of the other legal proceedings to which the Company is a party will have a material adverse effect on the Company’s results of operations, cash flows or financial condition.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Jul. 31, 2014
Legal Proceedings and Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Note 17—Commitments and Contingencies
	Purchase Commitments
	The Company had purchase commitments of $2.3 million as of July 31, 2014.
	Lease Commitments
	The future minimum payments for operating leases as of July 31, 2014 are as follows:
	(in thousands)
	Year ending July 31:
	2015	$	2,801
	2016		1,383
	2017		1,146
	2018		934
	2019		812
	Thereafter		235
	Total payments	$	7,311
	Rental expense under operating leases was $6.4 million, $5.9 million and $4.1 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. In addition, connectivity charges under operating leases were $10.4 million, $11.8 million and $16.3 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively.
	Letters of Credit
	As of July 31, 2014, the Company had letters of credit outstanding totaling $3.7 million primarily for collateral to secure mortgage repayments and for IDT Telecom’s business. The letters of credit outstanding as of July 31, 2014 expire as follows: $0.9 million in the year ending July 31, 2015 and $2.8 million in August 2015.
	Performance Bonds
	IDT Payment Services and IDT Telecom have performance bonds issued through third parties for the benefit of various states in order to comply with the states’ financial requirements for money remittance licenses and telecommunications resellers, respectively. At July 31, 2014, the Company had aggregate performance bonds of $10.0 million outstanding.
	Customer Deposits
	As of July 31, 2014 and 2013, “Customer deposits” in the Company’s consolidated balance sheets included refundable customer deposits of $62.7 million and $28.7 million, respectively, related to IDT Financial Services, the Company’s Gibraltar-based bank.
	Substantially Restricted Cash and Cash Equivalents
	At July 31, 2014 and 2013, “Cash and cash equivalents” in the Company’s consolidated balance sheet included an aggregate of $12.9 million and $7.8 million, respectively, set aside by IDT Payment Services and IDT Financial Services that was unavailable for other purposes.
	Restricted Cash and Cash Equivalents
	Restricted cash and cash equivalents consist of the following:
	July 31	2014		2013
	(in thousands)
	Restricted cash and cash equivalents—short-term
	Letters of credit related	$	665	$	3,189
	IDT Financial Services customer deposits		64,415		31,076
	Other		626		723
	Total short-term		65,706		34,988
	Restricted cash and cash equivalents—long-term
	Letters of credit related		2,763		2,767
	Total restricted cash and cash equivalents	$	68,469	$	37,755

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Jul. 31, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Note 18—Related Party Transactions
	See Note 13 for a description of the Zedge transactions under “Sales of Stock of Subsidiaries.”
	The Company entered into various agreements with Straight Path prior to the Straight Path Spin-Off including (1) a Separation and Distribution Agreement to effect the separation and provide a framework for the Company’s relationship with Straight Path after the spin-off, (2) a Tax Separation Agreement, which sets forth the responsibilities of the Company and Straight Path with respect to, among other things, liabilities for federal, state, local and foreign taxes for periods before and including the spin-off, the preparation and filing of tax returns for such periods and disputes with taxing authorities regarding taxes for such periods, and (3) a Transition Services Agreement, which provides for certain services to be performed by the Company to facilitate Straight Path’s transition into a separate publicly-traded company. These agreements provide for, among other things, the allocation between the Company and Straight Path of employee benefits, taxes and other liabilities and obligations attributable to periods prior to the spin-off, and provision of certain services by the Company to Straight Path following the spin-off, including services relating to human resources and employee benefits administration, treasury, accounting, tax, external reporting, and legal. Straight Path transitioned accounting and external reporting services from the Company to a third party in the first quarter of fiscal 2015. In addition, the Company and Straight Path have entered into a license agreement whereby each of the Company, Straight Path and their subsidiaries granted and will grant a license to the other to utilize patents held by each entity.
	The Separation and Distribution Agreement also includes that the Company is obligated to reimburse Straight Path for the payment of any liabilities of Straight Path arising or related to the period prior to the Straight Path Spin-Off. The following table summarizes the change in the balance of the Company’s estimated liability to Straight Path, which is included in “Other current liabilities” in the accompanying consolidated balance sheet:
	Year ended July 31	2014
	(in thousands)
	Balance at beginning of year	$	931
	Additional liability		1,930
	Payments		(1,001	)
	Balance at end of year	$	1,860
	Pursuant to the Separation and Distribution Agreement, the Company indemnifies Straight Path and Straight Path indemnifies the Company for losses related to the failure of the other to pay, perform or otherwise discharge, any of the liabilities and obligations set forth in the agreement. Pursuant to the Tax Separation Agreement, the Company indemnifies Straight Path from all liability for taxes of Straight Path or any of its subsidiaries or relating to the Straight Path business with respect to taxable periods ending on or before the Straight Path Spin-Off, from all liability for taxes of the Company, other than Straight Path and its subsidiaries, for any taxable period, and from all liability for taxes due to the Straight Path Spin-Off.
	The Company’s selling, general and administrative expenses were reduced by $0.8 million in fiscal 2014 as a result of the fees the Company charged to Straight Path for services provided pursuant to the Transition Services Agreement. At July 31, 2014, other current assets reported in the Company’s consolidated balance sheet included receivables from Straight Path of $29,000.
	The Company entered into various agreements with Genie prior to the Genie Spin-Off including a Separation and Distribution Agreement to effect the separation and provide a framework for the Company’s relationship with Genie after the spin-off, and a Transition Services Agreement, which provides for certain services to be performed by the Company and Genie to facilitate Genie’s transition into a separate publicly-traded company. These agreements provide for, among other things, (1) the allocation between the Company and Genie of employee benefits, taxes and other liabilities and obligations attributable to periods prior to the spin-off, (2) transitional services to be provided by the Company relating to human resources and employee benefits administration, (3) the allocation of responsibilities relating to employee compensation and benefit plans and programs and other related matters, (4) finance, accounting, tax, internal audit, facilities, external reporting, investor relations and legal services to be provided by the Company to Genie following the spin-off and (5) specified administrative services to be provided by Genie to certain of the Company’s foreign subsidiaries. In addition, the Company entered into a Tax Separation Agreement with Genie, which sets forth the responsibilities of the Company and Genie with respect to, among other things, liabilities for federal, state, local and foreign taxes for periods before and including the spin-off, the preparation and filing of tax returns for such periods and disputes with taxing authorities regarding taxes for such periods.
	Pursuant to the Separation and Distribution Agreement, the Company indemnifies Genie and Genie indemnifies the Company for losses related to the failure of the other to pay, perform or otherwise discharge, any of the liabilities and obligations set forth in the agreement. Pursuant to the Tax Separation Agreement, the Company indemnifies Genie from all liability for the Company’s taxes with respect to any taxable period, and Genie indemnifies the Company from all liability for taxes of Genie and its subsidiaries with respect to any taxable period, including, without limitation, the ongoing tax audits related to Genie’s business.
	The Company’s Chairman of the Board and former Chief Executive Officer, Howard S. Jonas, is the controlling stockholder and Chairman of the Board of Genie. The Company’s selling, general and administrative expenses were reduced by $3.1 million, $3.8 million and $2.7 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively, as a result of the fees the Company charged to Genie for services provided pursuant to the Transition Services Agreement, net of the amounts charged by Genie to the Company. At July 31, 2014 and 2013, other current assets reported in the Company’s consolidated balance sheet included receivables from Genie of $0.5 million and $0.6 million, respectively.
	IDT Energy, Inc., a subsidiary of Genie, supplied electricity to the Company’s facilities in Piscataway, New Jersey, and Newark, New Jersey through January 2013. IDT Energy also supplied natural gas to the Company’s Newark, New Jersey building until April 2013, and IDT Energy supplies natural gas to the Company’s facility in Piscataway, New Jersey. In fiscal 2014, fiscal 2013 and fiscal 2012, IDT Energy, Inc. billed the Company $16,000, $21,000 and $0.5 million, respectively.
	The Company provides office space, certain connectivity and other services to Jonas Media Group, a publishing firm owned by Howard Jonas. Billings for such services were $18,000, $27,000 and $29,000 in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. The balance owed to the Company by Jonas Media Group was $4,000 and $6,000 as of July 31, 2014 and 2013, respectively.
	The Company obtains insurance policies from several insurance brokers, one of which is IGM Brokerage Corp. (“IGM”). IGM was, until his death in October 2009, owned by Irwin Jonas, father of Howard Jonas, and the Company’s General Counsel, Joyce J. Mason. IGM is currently owned by Irwin Jonas’ widow—the mother of Howard Jonas and Joyce Mason. Jonathan Mason, husband of Joyce Mason and brother-in-law of Howard Jonas, provides insurance brokerage services via IGM. Based on information the Company received from IGM, the Company believes that (1) IGM received commissions and fees from payments made by the Company (including payments from third party brokers) in the aggregate amounts of $20,000 in fiscal 2014, $15,000 in fiscal 2013 and $19,000 in fiscal 2012, which fees and commissions inured to the benefit of Mr. Mason, and (2) the total payments made by the Company to IGM for various insurance policies were nil in fiscal 2014 and fiscal 2013, and $0.2 million in fiscal 2012. Neither Howard Jonas nor Joyce Mason has any ownership or other interest in IGM or the commissions paid to IGM other than via the familial relationships with their mother and Jonathan Mason.
	Mason and Company Consulting, LLC (“Mason and Co.”), a company owned solely by Jonathan Mason, receives an annual fee for the insurance brokerage referral and placement of the Company’s health benefit plan with Brown & Brown Metro, Inc. Based on information the Company received from Jonathan Mason, the Company believes that Mason and Co. received from Brown & Brown Metro, Inc. commissions and fees from payments made by the Company in the amount of $18,000 in fiscal 2014, $24,000 in fiscal 2013 and $20,000 in fiscal 2012. Neither Howard Jonas nor Joyce Mason has any ownership or other interest in Mason and Co. or the commissions paid to Mason and Co., other than via the familial relationships with Jonathan Mason.
	Since August 2009, IDT Domestic Telecom, Inc., a subsidiary of the Company, has leased space in a building in the Bronx, New York. Howard Jonas and Shmuel Jonas, the Company’s Chief Executive Officer, and the son of Howard Jonas, are members of the limited liability company that owns the building. IDT Domestic Telecom rented office, storage and parking space for two years for $0.1 million per year and incurred costs of $0.1 million to build-out the space. In August 2009, the limited liability company was paid an aggregate of $0.3 million for the lease and the build-out costs. The initial lease expired at the end of April 2012. For the six month period from May 1, 2012 to October 31, 2012, IDT Domestic Telecom was charged aggregate rent of $34,512. The parties entered into a new lease, which became effective November 1, 2012 and has a one-year term, with a one-year renewal option for IDT Domestic Telecom with the same terms. Aggregate annual rent under the new lease is $69,025.
	The Company had net loans receivable outstanding from employees aggregating $0.2 million as of July 31, 2014 and 2013, which are included in “Other current assets” in the accompanying consolidated balance sheets.

Defined_Contribution_Plans

Defined Contribution Plans	12 Months Ended
	Jul. 31, 2014
Defined Contribution Plans [Abstract]	'
Defined Contribution Plans	'
	Note 19—Defined Contribution Plans
	The Company maintains a 401(k) Plan available to all employees meeting certain eligibility criteria. The Plan permits participants to contribute up to 20% of their salary, not to exceed the limits established by the Internal Revenue Code. The Plan provides for discretionary matching contributions of 50%, up to the first 6% of compensation. The discretionary matching contributions vest over the first five years of employment. The Plan permits the discretionary matching contributions to be granted as of December 31 of each year. All contributions made by participants vest immediately into the participant’s account. In fiscal 2014, fiscal 2013 and fiscal 2012, the Company’s cost for contributions to the Plan was $1.1 million, $1.1 million and $0.9 million, respectively. In fiscal 2014, fiscal 2013 and fiscal 2012, the Company contributed 72,281 shares, 51,861 shares and 92,843 shares, respectively, of the Company’s Class B common stock to the Plan for matching contributions. The Company’s Class A common stock and Class B common stock are not investment options for the Plan’s participants.

Business_Segment_Information

Business Segment Information	12 Months Ended
	Jul. 31, 2014
Business Segment Information [Abstract]	'
Business Segment Information	'
	Note 20—Business Segment Information
	The Company has three reportable business segments, Telecom Platform Services, Consumer Phone Services and Zedge. Telecom Platform Services and Consumer Phone Services comprise the IDT Telecom division. Operating segments not reportable individually are included in All Other. The Company’s reportable segments are distinguished by types of service, customers and methods used to provide their services. The operating results of these business segments are regularly reviewed by the Company’s chief operating decision maker.
	The Telecom Platform Services segment provides retail telecommunications and payment offerings as well as wholesale international long distance traffic termination. The Consumer Phone Services segment provides consumer local and long distance services in certain U.S. states. Zedge owns and operates an online platform for mobile phone consumers interested in obtaining free, high-quality games, apps, and mobile phone customization including ringtones, wallpapers, and notification sounds. All Other includes Fabrix, a software development company offering a cloud-based scale-out storage and computing platform optimized for big data, virtualization and media storage, processing and delivery. The Company sold Fabrix in October 2014 (see Note 22). All Other also includes the Company’s real estate holdings and other, smaller, businesses. Corporate costs include certain services, such as compensation, consulting fees, treasury and accounts payable, tax and accounting services, human resources and payroll, corporate purchasing, corporate governance including Board of Directors’ fees, internal and external audit, investor relations, corporate insurance, corporate legal, business development, and other corporate-related general and administrative expenses including, among others, facilities costs, charitable contributions and travel, as well as depreciation expense on corporate assets. Corporate does not generate any revenues, nor does it incur any direct cost of revenues.
	The accounting policies of the segments are the same as the accounting policies of the Company as a whole. The Company evaluates the performance of its business segments based primarily on income (loss) from operations. IDT Telecom depreciation and amortization are allocated to Telecom Platform Services and Consumer Phone Services because the related assets are not tracked separately by segment. There are no other significant asymmetrical allocations to segments.
	Operating results for the business segments of the Company are as follows:
	(in thousands)	Telecom			Consumer			Zedge			All Other			Corporate			Total
		Platform			Phone
		Services			Services
	Year ended July 31, 2014
	Revenues	$	1,615,570		$	11,023		$	6,535		$	18,413		$	—		$	1,651,541
	Income (loss) from operations		45,062			1,797			314			(2,049	)		(15,284	)		29,840
	Depreciation and amortization		13,776			—			967			1,545			30			16,318
	Year ended July 31, 2013
	Revenues	$	1,588,071		$	14,514		$	5,811		$	12,221		$	—		$	1,620,617
	Income (loss) from operations		48,661			1,824			340			(7,433	)		(14,001	)		29,391
	Depreciation and amortization		12,342			1			798			1,673			96			14,910
	Impairment of building and improvements		—			—			—			4,359			—			4,359
	Year ended July 31, 2012
	Revenues	$	1,477,762		$	19,307		$	3,793		$	5,421		$	—		$	1,506,283
	Income (loss) from operations		5,910			4,062			(248	)		(3,668	)		(13,152	)		(7,096	)
	Depreciation and amortization		14,215			9			652			1,512			260			16,648
	Telecom Platform Services’ income from operations in fiscal 2013 included net gains of $9.3 million related to legal matters.
	Telecom Platform Services’ income from operations in fiscal 2012 included other operating losses, net of $15.9 million comprised of $6.5 million for estimated losses from pending litigation, a loss of $11.0 million from the settlement of litigation with T-Mobile (see Note 7) and a $0.2 million loss on the settlement of an unrelated claim, net of a gain of $1.8 million for cash received from Broadstripe, LLC in settlement of the Company’s claim stemming from Broadstripe, LLC’s rejection of its telephony services agreements with the Company (see Note 7).
	Total assets for the reportable segments are not provided because a significant portion of the Company’s assets are servicing multiple segments and the Company does not track such assets separately by segment.
	Geographic Information
	Revenue from customers located outside of the United States as a percentage of total revenues from continuing operations and revenue from customers located in the United Kingdom as a percentage of total revenues from continuing operations were as follows. Revenues by country are determined based on selling location.
	Year ended July 31	2014			2013			2012
	Revenue from customers located outside of the United States		30	%		23	%		29	%
	Revenue from customers located in the United Kingdom		19	%		13	%		14	%
	Net long-lived assets and total assets held outside of the United States, which are located primarily in Western Europe, were as follows:
	(in thousands)	United			Foreign			Total
		States			Countries
	31-Jul-14
	Long-lived assets, net	$	79,281		$	2,479		$	81,760
	Total assets		284,249			196,682			480,931
	31-Jul-13
	Long-lived assets, net	$	77,580		$	3,162		$	80,742
	Total assets		294,337			141,070			435,407
	31-Jul-12
	Long-lived assets, net	$	81,668		$	3,899		$	85,567
	Total assets		310,209			140,905			451,114

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
	Jul. 31, 2014
Selected Quarterly Financial Data [Abstract]	'
Selected Quarterly Financial Data	'
	Note 21—Selected Quarterly Financial Data (Unaudited)
	The table below presents selected quarterly financial data of the Company for its fiscal quarters in fiscal 2013 and fiscal 2012:
	Quarter Ended								Income			Net income			Income (loss) per share						Income (loss) per share
									(loss)			(loss)			—basic						—diluted
	(in thousands, except per share data)		Revenues		Direct cost		Income		from			attributable			From			Net			From			Net
					of revenues		from		continuing			to IDT			continuing			income			continuing			income
							operations		operations			Corporation			operations			(loss)			operations			(loss)
	2014:00:00
	October 31		$	420,670	$	350,319	$	7,283	$	4,050		$	3,523		$	0.17		$	0.17		$	0.15		$	0.15
	January 31			406,423		335,258		7,574		2,973			2,535			0.12			0.12			0.11			0.11
	30-Apr			403,761		332,376		9,170		5,599			5,017			0.22			0.22			0.22			0.22
	31-Jul			420,687		349,313		5,813		8,388			7,709			0.34			0.34			0.33			0.33
	TOTAL		$	1,651,541	$	1,367,266	$	29,840	$	21,010		$	18,784		$	0.85		$	0.85		$	0.82		$	0.82
	2013:00:00
	October 31		$	400,117	$	335,251	$	6,684	$	5,620		$	3,614		$	0.24		$	0.17		$	0.23		$	0.16
	31-Jan			411,456		344,486		5,655		3,908			2,953			0.16			0.14			0.15			0.13
	April 30(a)			396,935		331,163		15,687		10,082			8,691			0.46			0.42			0.43			0.39
	July 31(b)			412,109		344,673		1,365		(1,532	)		(3,651	)		(0.09	)		(0.17	)		(0.09	)		(0.17	)
	TOTAL		$	1,620,617	$	1,355,573	$	29,391	$	18,078		$	11,607		$	0.77		$	0.56		$	0.72		$	0.52
	(a)	Included in income from operations was other operating gains of $9.6 million related to legal matters.
	(b)	Included in income from operations was a charge for impairment of building and improvements of $4.4 million.

Subsequent_Event

Subsequent Event	12 Months Ended
	Jul. 31, 2014
Subsequent Event [Abstract]	'
Subsequent Event	'
	Note 22—Subsequent Event
	On October 8, 2014, the Company completed the sale of its interests in Fabrix to Telefonaktiebolget LM Ericsson (publ) (“Ericsson”). The final sale price for 100% of the shares in Fabrix was $95 million in cash, excluding transaction costs and working capital and other adjustments. The Company owned approximately 78% of Fabrix on a fully diluted basis. The Company’s share of the sale price, net of transaction costs, is expected to be approximately $73 million in cash. The Company and the other shareholders have placed $13 million of their proceeds in escrow for the resolution of post-closing claims that may arise. Any unclaimed escrow balance will be released in two tranches over a period of 18 months.

Description_of_Business_and_Su1

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Jul. 31, 2014
Description of Business and Summary of Significant Accounting Policies [Abstract]	'
Description of Business	'
	Description of Business
	IDT Corporation (“IDT” or the “Company”) is a multinational holding company with operations primarily in the telecommunications and payment industries. The Company has three reportable business segments, Telecom Platform Services, Consumer Phone Services and Zedge Holdings, Inc. (“Zedge”). Telecom Platform Services provides retail telecommunications and payment offerings as well as wholesale international long distance traffic termination. Consumer Phone Services provides consumer local and long distance services in certain U.S. states. Telecom Platform Services and Consumer Phone Services comprise the IDT Telecom division. Zedge owns and operates an online platform for mobile phone consumers interested in obtaining free, high-quality games, apps, and mobile phone customization including ringtones, wallpapers, and notification sounds. Operating segments not reportable individually are included in All Other. All Other includes Fabrix Systems Ltd. (“Fabrix”), a software development company offering a cloud-based scale-out storage and computing platform optimized for big data, virtualization and media storage, processing and delivery. The Company sold Fabrix in October 2014 (see Note 22). All Other also includes the Company’s real estate holdings and other, smaller, businesses.
	On July 31, 2013, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Straight Path Communications Inc. (“Straight Path”), to the Company’s stockholders of record as of the close of business on July 25, 2013 (the “Straight Path Spin-Off”) (see Note 2). On October 28, 2011, the Company completed a pro rata distribution of the common stock of the Company’s subsidiary, Genie Energy Ltd. (“Genie”), to the Company’s stockholders of record as of the close of business on October 21, 2011 (the “Genie Spin-Off”) (see Note 2). Straight Path and Genie met the criteria to be reported as discontinued operations and accordingly, their assets, liabilities, results of operations and cash flows are classified as discontinued operations for all periods presented.
Basis of Consolidation and Accounting for Investments	'
	Basis of Consolidation and Accounting for Investments
	The method of accounting applied to long-term investments, whether consolidated, equity or cost, involves an evaluation of the significant terms of each investment that explicitly grant or suggest evidence of control or influence over the operations of the investee and also includes the identification of any variable interests in which the Company is the primary beneficiary. The consolidated financial statements include the Company’s controlled subsidiaries. In addition, the Company has not identified any variable interests in which the Company is the primary beneficiary. All significant intercompany accounts and transactions between the consolidated subsidiaries are eliminated.
	Investments in businesses that the Company does not control, but in which the Company has the ability to exercise significant influence over operating and financial matters, are accounted for using the equity method. Investments in which the Company does not have the ability to exercise significant influence over operating and financial matters are accounted for using the cost method. Investments in hedge funds are accounted for using the equity method unless the Company’s interest is so minor that it has virtually no influence over operating and financial policies, in which case these investments are accounted for using the cost method. At July 31, 2014 and 2013, the Company had $9.4 million and $8.1 million, respectively, in investments accounted for using the equity method, and $1.8 million and $1.5 million, respectively, in investments accounted for using the cost method. Equity and cost method investments are included in “Other current assets” or “Investments” in the accompanying consolidated balance sheets. The Company periodically evaluates its equity and cost method investments for impairment due to declines considered to be other than temporary. If the Company determines that a decline in fair value is other than temporary, then a charge to earnings is recorded in “Other (expense) income, net” in the accompanying consolidated statements of income, and a new basis in the investment is established.
Reclassifications	'
	Reclassifications
	Certain prior year amounts were reclassified to conform to the current year’s presentation:
		●	In the consolidated balance sheet, $4.6 million previously included in “Restricted cash and cash equivalents—long-term” at July 31, 2013 was reclassified to “Cash and cash equivalents”;
		●	In the consolidated statements of cash flows, cash used for “Restricted cash and cash equivalents” in the years ended July 31, 2013 and 2012 of $2.1 million and $2.0 million, respectively, was reclassified to “Cash and cash equivalents”; and
		●	In the consolidated statement of cash flows, $8.7 million previously included in “Restricted cash and cash equivalents” at July 31, 2011 was reclassified to “Cash and cash equivalents”.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.
Revenue Recognition	'
	Revenue Recognition
	Telephone service, which includes domestic and international long distance, local service, and wholesale carrier telephony services is recognized as revenue when services are provided, primarily based on usage and/or the assessment of fees. Revenue from Boss Revolution PIN-less international calling service and from sales of calling cards, net of customer discounts, is deferred until the service or the cards are used or, calling card administrative fees are imposed, thereby reducing the Company’s outstanding obligation to the customer, at which time revenue is recognized. Domestic and international airtime top-up revenue is recognized upon redemption. International airtime top-up enables customers to purchase airtime for a prepaid mobile telephone in another country.
	IDT Telecom enters into reciprocal transactions pursuant to which IDT Telecom is committed to purchase a specific number of minutes to specific destinations at specified rates, and the counterparty is committed to purchase from IDT Telecom a specific number of minutes to specific destinations at specified rates. The number of minutes purchased and sold in a reciprocal transaction is not necessarily equal. The rates in these reciprocal transactions are generally greater than prevailing market rates. In addition, IDT Telecom enters into transactions in which it swaps minutes with another carrier. The Company recognizes revenue and the related direct cost of revenue for these reciprocal and swap transactions based on the fair value of the minutes.
	Zedge revenues from traditional web/mobile web and Android/iOS applications are recognized based on blocks of impressions or ad views. Revenues from mobile games are recognized upon download by the end user.
	Revenue from Fabrix for software licenses and maintenance support was deferred and recognized on a straight-line basis from the date on which delivered orders were accepted by the customer over the period that the support was expected to be provided since sufficient vendor-specific objective evidence of fair value to allocate revenues to the various deliverables did not exist in fiscal 2014, fiscal 2013 or fiscal 2012.
Direct Cost of Revenues	'
	Direct Cost of Revenues
	Direct cost of revenues for IDT Telecom consists primarily of termination and origination costs, toll-free costs, and network costs—including customer/carrier interconnect charges and leased fiber circuit charges. These costs include an estimate of charges for which invoices have not yet been received, and estimated amounts for pending disputes with other carriers. Subsequent adjustments to these estimates may occur after the invoices are received for the actual costs incurred, but these adjustments generally are not material to the Company’s results of operations. Direct cost of revenues for IDT Telecom also includes the cost of airtime top-up minutes.
	Direct cost of revenues for Zedge consists of ad server costs, web hosting charges, and copyright/infringement prevention costs.
	Direct cost of revenues for Fabrix consisted primarily of customer support expenses.
	Direct cost of revenues excludes depreciation and amortization expense.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents.
Restricted Cash and Cash Equivalents	'
	Restricted Cash and Cash Equivalents
	The Company classifies the change in its restricted cash and cash equivalents as an operating activity in the accompanying consolidated statements of cash flows because the restrictions are directly related to the operations of IDT Financial Services, the Company’s Gibraltar-based bank, and IDT Telecom.
Substantially Restricted Cash and Cash Equivalents	'
	Substantially Restricted Cash and Cash Equivalents
	IDT Payment Services, which provides the Company’s international money transfer services in the United States, and IDT Financial Services set aside certain cash balances in accordance with banking regulations, credit card issuer requirements or license compliance. These balances are included in “Cash and cash equivalents” in the Company’s consolidated balance sheet. The balances are not legally restricted, however the Company treats these balances as substantially restricted and unavailable for other purposes.
Marketable Securities	'
	Marketable Securities
	The Company’s investments in marketable securities are classified as “available-for-sale.” Available-for-sale securities are required to be carried at their fair value, with unrealized gains and losses (net of income taxes) that are considered temporary in nature recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. The Company uses the specific identification method in computing the gross realized gains and gross realized losses on the sales of marketable securities. The Company periodically evaluates its investments in marketable securities for impairment due to declines in market value considered to be other than temporary. Such impairment evaluations include, in addition to persistent, declining market prices, general economic and Company-specific evaluations. If the Company determines that a decline in market value is other than temporary, then a charge to operations is recorded in “Other (expense) income, net” in the accompanying consolidated statements of income and a new cost basis in the investment is established.
Long-Lived Assets	'
	Long-Lived Assets
	Equipment, buildings, computer software and furniture and fixtures are recorded at cost and are depreciated on a straight-line basis over their estimated useful lives, which range as follows: equipment—5, 7 or 20 years; buildings—40 years; computer software—2, 3 or 5 years and furniture and fixtures—5, 7 or 10 years. Leasehold improvements are recorded at cost and are depreciated on a straight-line basis over the term of their lease or their estimated useful lives, whichever is shorter.
	Costs associated with obtaining the right to use trademark and patents owned by third parties are capitalized and amortized on a straight-line basis over the term of the relevant trademark and patent licenses. The fair value of technology and domain names, customer lists, and trademark acquired in a business combination accounted for under the purchase method are amortized over their estimated useful lives as follows: technology and domain names are amortized on a straight-line basis over the 3 year estimated useful lives; customer lists are amortized ratably over the approximately 15 year period of expected cash flows; and trademark is amortized on a straight-line basis over the 5 year period of expected cash flows.
	The Company tests the recoverability of its long-lived assets with finite useful lives whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company tests for recoverability based on the projected undiscounted cash flows to be derived from such asset. If the projected undiscounted future cash flows are less than the carrying value of the asset, the Company will record an impairment loss, if any, based on the difference between the estimated fair value and the carrying value of the asset. The Company generally measures fair value by considering sale prices for similar assets or by discounting estimated future cash flows from such asset using an appropriate discount rate. Cash flow projections and fair value estimates require significant estimates and assumptions by management. Should the estimates and assumptions prove to be incorrect, the Company may be required to record impairments in future periods and such impairments could be material.
Goodwill	'
	Goodwill
	Goodwill is the excess of the acquisition cost of businesses over the fair value of the identifiable net assets acquired. Goodwill and other indefinite lived intangible assets are not amortized. These assets are reviewed annually (or more frequently under various conditions) for impairment using a fair value approach. The goodwill impairment assessment involves estimating the fair value of the reporting unit and comparing it to its carrying amount, which is known as Step 1. If the carrying value of the reporting unit exceeds its estimated fair value, Step 2 is performed to determine if an impairment of goodwill is required. The fair value of the reporting units is estimated using discounted cash flow methodologies, as well as considering third party market value indicators. Goodwill impairment is measured by the excess of the carrying amount of the reporting unit’s goodwill over its implied fair value. Calculating the fair value of the reporting units, and allocating the estimated fair value to all of the tangible assets, intangible assets and liabilities, requires significant estimates and assumptions by management. Should the estimates and assumptions regarding the fair value of the reporting units prove to be incorrect, the Company may be required to record impairments to its goodwill in future periods and such impairments could be material.
	The Company has the option to perform a qualitative assessment to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. However, the Company may elect to perform the two-step quantitative goodwill impairment test even if no indications of a potential impairment exist.
	For its reporting unit with zero or negative carrying amount, the Company performs Step 2 of the goodwill impairment test if it is more likely than not that a goodwill impairment exists. In determining whether it is more likely than not that goodwill impairment exists, the Company considers whether there are any adverse qualitative factors indicating that impairment may exist.
Advertising Expense	'
	Advertising Expense
	Cost of advertising is charged to selling, general and administrative expenses in the period in which it is incurred. In fiscal 2014, fiscal 2013 and fiscal 2012, advertising expense was $17.2 million, $13.1 million and $17.0 million, respectively.
Research and Development Costs	'
	Research and Development Costs
	Costs for research and development are charged to expense as incurred. Research and development costs were primarily incurred by Fabrix.
Capitalized Internal Use Software Costs	'
	Capitalized Internal Use Software Costs
	The Company capitalizes the cost of internal-use software that has a useful life in excess of one year. These costs consist of payments made to third parties and the salaries of employees working on such software development. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they allow the software to perform a task it previously did not perform. Software maintenance and training costs are expensed in the period in which they are incurred. Capitalized internal use software costs are amortized on a straight-line basis over their estimated useful lives. Amortization expense related to such capitalized software in fiscal 2014, fiscal 2013 and fiscal 2012 was $7.6 million, $6.3 million and $5.8 million, respectively. Unamortized capitalized internal use software costs at July 31, 2014 and 2013 were $13.2 million and $10.2 million, respectively.
Repairs and Maintenance	'
	Repairs and Maintenance
	The Company charges the cost of repairs and maintenance, including the cost of replacing minor items not constituting substantial betterment, to selling, general and administrative expenses as these costs are incurred.
Foreign Currency Translation	'
	Foreign Currency Translation
	Assets and liabilities of foreign subsidiaries denominated in foreign currencies are translated to U.S. Dollars at end-of-period rates of exchange, and their monthly results of operations are translated to U.S. Dollars at the average rates of exchange for that month. Gains or losses resulting from such foreign currency translations are recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are reported in “Other (expense) income, net” in the accompanying consolidated statements of income.
Income Taxes	'
	Income Taxes
	The Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the period in which related temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in its assessment of a valuation allowance. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date of such change.
	The Company uses a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. The Company determines whether it is more-likely-than-not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. Tax positions that meet the more-likely-than-not recognition threshold are measured to determine the amount of tax benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement. Differences between tax positions taken in a tax return and amounts recognized in the financial statements will generally result in one or more of the following: an increase in a liability for income taxes payable, a reduction of an income tax refund receivable, a reduction in a deferred tax asset, or an increase in a deferred tax liability.
	The Company classifies interest and penalties on income taxes as a component of income tax expense.
Contingencies	'
	Contingencies
	The Company accrues for loss contingencies when both (a) information available prior to issuance of the financial statements indicates that it is probable that a liability had been incurred at the date of the financial statements and (b) the amount of loss can reasonably be estimated. When the Company accrues for loss contingencies and the reasonable estimate of the loss is within a range, the Company records its best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company accrues the minimum amount in the range. The Company discloses an estimated possible loss or a range of loss when it is at least reasonably possible that a loss may have been incurred.
Earnings Per Share	'
	Earnings Per Share
	Basic earnings per share is computed by dividing net income attributable to all classes of common stockholders of the Company by the weighted average number of shares of all classes of common stock outstanding during the applicable period. Diluted earnings per share is determined in the same manner as basic earnings per share, except that the number of shares is increased to include restricted stock still subject to risk of forfeiture and to assume exercise of potentially dilutive stock options using the treasury stock method, unless the effect of such increase is anti-dilutive.
	The weighted-average number of shares used in the calculation of basic and diluted earnings per share attributable to the Company’s common stockholders consists of the following:
	Year ended July 31		2014		2013		2012
	(in thousands)
	Basic weighted-average number of shares			22,009		20,876		20,717
	Effect of dilutive securities:
	Stock options			92		9		—
	Non-vested restricted Class B common stock			836		1,430		1,343
	Diluted weighted-average number of shares			22,937		22,315		22,060
	The following outstanding stock options were excluded from the calculation of diluted earnings per share because the exercise price of the stock option was greater than the average market price of the Company’s stock during the period:
	Year ended July 31		2014		2013		2012
	(in thousands)
	Shares excluded from the calculation of diluted earnings per share			70		611		619
Stock-Based Compensation	'
	Stock-Based Compensation
	The Company recognizes compensation expense for all of its grants of stock-based awards based on the estimated fair value on the grant date. Compensation cost for awards is recognized using the straight-line method over the vesting period. Stock-based compensation is included in selling, general and administrative expense.
Taxes Collected from Customers and Remitted to Governmental Authorities	'
	Taxes Collected from Customers and Remitted to Governmental Authorities
	The Company collects taxes from its customers that are remitted to governmental authorities in the normal course of its operations. These taxes, which are imposed on or are concurrent with specific revenue-producing transactions, include Universal Service Fund (“USF”) charges, sales, use, value added and certain excise taxes. The Company currently records USF charges that are billed to customers on a gross basis in its results of operations, and records other taxes on a net basis. USF charges in the amount of $0.6 million, $0.8 million and $1.1 million in fiscal 2014, fiscal 2013 and fiscal 2012, respectively, were recorded on a gross basis and included in “Revenues” and “Direct cost of revenues” in the accompanying consolidated statements of income.
Vulnerability Due to Certain Concentrations	'
	Vulnerability Due to Certain Concentrations
	Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash, cash equivalents, restricted cash and cash equivalents, marketable securities, investments in hedge funds and trade accounts receivable. The Company holds cash and cash equivalents at several major financial institutions, which often exceed FDIC insurance limits. Historically, the Company has not experienced any losses due to such concentration of credit risk. The Company’s temporary cash investments policy is to limit the dollar amount of investments with any one financial institution and monitor the credit ratings of those institutions. While the Company may be exposed to credit losses due to the nonperformance of the holders of its deposits, the Company does not expect the settlement of these transactions to have a material effect on its results of operations, cash flows or financial condition.
	Concentration of credit risk with respect to trade accounts receivable is limited due to the large number of customers in various geographic regions and industry segments comprising the Company’s customer base. No single customer accounted for more than 10% of consolidated revenues in fiscal 2014, fiscal 2013 or fiscal 2012. However, the Company’s five largest customers collectively accounted for 12.0%, 10.0% and 8.1% of its consolidated revenues from continuing operations in fiscal 2014, fiscal 2013 and fiscal 2012, respectively. The Company’s customers with the five largest receivables balances collectively accounted for 22.1% and 16.6% of the consolidated gross trade accounts receivable at July 31, 2014 and 2013, respectively. This concentration of customers increases the Company’s risk associated with nonpayment by those customers. In an effort to reduce such risk, the Company performs ongoing credit evaluations of its significant retail telecom, wholesale termination and cable telephony customers. In addition, the Company attempts to mitigate the credit risk related to specific wholesale termination customers by also buying services from the customer, in order to create an opportunity to offset its payables and receivables and reduce its net trade receivable exposure risk. When it is practical to do so, the Company will increase its purchases from wholesale termination customers with receivable balances that exceed the Company’s applicable payables in order to maximize the offset and reduce its credit risk.
Allowance for Doubtful Accounts	'
	Allowance for Doubtful Accounts
	The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the accounts receivable balance. The allowance is determined based on known troubled accounts, historical experience and other currently available evidence. Doubtful accounts are written-off upon final determination that the trade accounts will not be collected. The change in the allowance for doubtful accounts is as follows:
	Year ended July 31		Balance at		Additions		Deductions(1)			Balance at
	(in thousands)		beginning of		charged to					end of year
			year		costs and
					expenses
	2014
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	13,079	$	500	$	(2,072	)	$	11,507
	2013
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	13,044	$	2,743	$	(2,708	)	$	13,079
	2012
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	15,364	$	2,098	$	(4,418	)	$	13,044
	-1	Primarily uncollectible accounts written off, net of recoveries.
Fair Value Measurements	'
	Fair Value Measurements
	Fair value of financial and non-financial assets and liabilities is defined as an exit price, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used to measure fair value, which prioritizes the inputs to valuation techniques used to measure fair value, is as follows:
	Level 1 –	quoted prices (unadjusted) in active markets for identical assets or liabilities.
	Level 2 –	quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument.
	Level 3 –	unobservable inputs based on the Company’s assumptions used to measure assets and liabilities at fair value.
	A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the assets and liabilities being measured and their placement within the fair value hierarchy.
Recently Issued Accounting Standard Not Yet Adopted	'
	Recently Issued Accounting Standard Not Yet Adopted
	In May 2014, the Financial Accounting Standards Board and the International Accounting Standards Board jointly issued a comprehensive new revenue recognition standard that will supersede most of the current revenue recognition guidance under U.S. GAAP and International Financial Reporting Standards (“IFRS”). The goals of the revenue recognition project were to clarify and converge the revenue recognition principles under U.S. GAAP and IFRS and to develop guidance that would streamline and enhance revenue recognition requirements. The Company will adopt this standard on August 1, 2017. Entities have the option of using either a full retrospective or modified retrospective approach for the adoption of the standard. The Company is evaluating the impact that the standard will have on its consolidated financial statements.
Recently Adopted Accounting Standard	'
	Recently Adopted Accounting Standard
	In April 2014, an accounting standard update was issued that changed the criteria for reporting discontinued operations and enhanced convergence of U.S. GAAP and IFRS reporting requirements for discontinued operations. The amendments in the update raise the threshold for a disposal to qualify as a discontinued operation and require new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. Early adoption is permitted but only for disposals (or classifications as held for sale) that have not been reported in previously issued financial statements. The Company adopted this standard update as of August 1, 2014. In accordance with this standard update, the Company does not expect the sale of Fabrix in October 2014 to qualify as a discontinued operation. The Company is unable to determine at this time whether the adoption of this standard update will have further effect on its financial position, results of operations or cash flows in the future for other disposals.

Description_of_Business_and_Su2

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Jul. 31, 2014
Description of Business and Summary of Significant Accounting Policies [Abstract]	'
Summary of Weighted-Average Number of Shares used in Calculation of Basic and Diluted Earnings Per Share	'
	Year ended July 31		2014		2013		2012
	(in thousands)
	Basic weighted-average number of shares			22,009		20,876		20,717
	Effect of dilutive securities:
	Stock options			92		9		—
	Non-vested restricted Class B common stock			836		1,430		1,343
	Diluted weighted-average number of shares			22,937		22,315		22,060
Summary of Outstanding Stock Options Excluded from Calculation of Diluted Earnings Per Share	'
	Year ended July 31		2014		2013		2012
	(in thousands)
	Shares excluded from the calculation of diluted earnings per share			70		611		619
Summary of Change in Allowance for Doubtful Accounts	'
	Year ended July 31		Balance at		Additions		Deductions(1)			Balance at
	(in thousands)		beginning of		charged to					end of year
			year		costs and
					expenses
	2014
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	13,079	$	500	$	(2,072	)	$	11,507
	2013
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	13,044	$	2,743	$	(2,708	)	$	13,079
	2012
	Reserves deducted from accounts receivable:
	Allowance for doubtful accounts		$	15,364	$	2,098	$	(4,418	)	$	13,044
	-1	Primarily uncollectible accounts written off, net of recoveries.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Jul. 31, 2014
Discontinued Operations [Abstract]	'
Summary Financial Data of Discontinued Operations	'
	Year ended July 31	2014		2013			2012
	(in thousands)
	REVENUES
	Straight Path	$	—	$	1,130		$	553
	Genie		—		—			45,796
	TOTAL	$	—	$	1,130		$	46,349
	(LOSS) INCOME BEFORE INCOME TAXES
	Straight Path	$	—	$	(4,621	)	$	4,862
	Genie		—		—			2,609
	TOTAL	$	—	$	(4,621	)	$	7,471
	NET (LOSS) INCOME
	Straight Path	$	—	$	(4,634	)	$	4,836
	Genie		—		—			1,015
	TOTAL	$	—	$	(4,634	)	$	5,851

Marketable_Securities_Tables

Marketable Securities (Tables)	12 Months Ended
	Jul. 31, 2014
Marketable Securities [Abstract]	'
Summary of Marketable Securities	'
	(in thousands)	Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	31-Jul-14
	Available-for-sale securities:
	Certificates of deposit*	$	10,375	$	—	$	—		$	10,375
	Equity securities		31		—		(9	)		22
	Municipal bonds		2,475		1		—			2,476
	TOTAL	$	12,881	$	1	$	(9	)	$	12,873
	31-Jul-13
	Available-for-sale securities:
	Certificates of deposit*	$	8,786	$	—	$	—		$	8,786
	Municipal bonds		898		—		—			898
	TOTAL	$	9,684	$	—	$	—		$	9,684
	*Each of the Company’s certificates of deposit has a CUSIP, was purchased in the secondary market through a broker and may be sold in the secondary market.
Summary of Available-for-Sale Securities	'
	(in thousands)	Fair Value
	Within one year	$	12,851
	After one year through five years		—
	After five years through ten years		—
	After ten years		—
	TOTAL	$	12,851

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Jul. 31, 2014
Fair Value Measurements [Abstract]	'
Summary of Assets Measured at Fair Value on Recurring Basis	'
	in thousands)	Level 1		Level 2		Level 3		Total
	31-Jul-14
	Available-for-sale securities	$	—	$	12,873	$	—	$	12,873
	31-Jul-13
	Available-for-sale securities	$	—	$	9,684	$	—	$	9,684

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Jul. 31, 2014
Property Plant And Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	July 31	2014			2013
	(in thousands)
	Equipment	$	438,899		$	436,127
	Land and buildings		53,895			51,294
	Computer software		116,775			105,449
	Leasehold improvements		42,190			45,141
	Furniture and fixtures		6,249			6,187
			658,008			644,198
	Less accumulated depreciation and amortization		(576,248	)		(563,456	)
	Property, plant and equipment, net	$	81,760		$	80,742

Goodwill_and_Other_Intangibles1

Goodwill and Other Intangibles (Tables)	12 Months Ended
	Jul. 31, 2014
Goodwill and Other Intangibles [Abstract]	'
Schedule of Change in Carrying Amount of Goodwill by Operating Segment	'
	(in thousands)	Telecom Platform		Zedge		Total
		Services
	Balance as of July 31, 2012	$	11,407	$	3,207	$	14,614
	Foreign currency translation adjustments		193		—		193
	Balance as of July 31, 2013		11,600		3,207		14,807
	Foreign currency translation adjustments		23		—		23
	Balance as of July 31, 2014	$	11,623	$	3,207	$	14,830
Schedule of Other Intangible Assets	'
	(in thousands)	Weighted		Gross		Accumulated			Net
		Average		Carrying		Amortization			Balance
		Amortization		Amount
		Period
	31-Jul-14
	Amortized intangible assets:
	Trademarks and patents		4.7 years	$	670	$	(335	)	$	335
	Technology and domain names		3.0 years		708		(68	)		640
	Customer lists		6.5 years		3,154		(2,387	)		767
	TOTAL		5.7 years	$	4,532	$	(2,790	)	$	1,742
	31-Jul-13
	Amortized intangible assets:
	Trademarks and patents		4.7 years	$	2,119	$	(1,715	)	$	404
	Customer lists		6.8 years		3,154		(2,168	)		986
	TOTAL		6.0 years	$	5,273	$	(3,883	)	$	1,390

Other_Operating_Gains_Losses_N1

Other Operating Gains (Losses), Net (Tables)	12 Months Ended
	Jul. 31, 2014
Other (Expense) Income, Net [Abstract]	'
Schedule of Other Operating Gains Net	'
	Year ended July 31	2014			2013		2012
	(in thousands)
	Telecom Platform Services—gains (losses) related to legal matters, net	$	650		$	9,251	$	(6,698	)
	Telecom Platform Services—loss on settlement of litigation (a)		—			—		(11,022	)
	Telecom Platform Services—gain on settlement of claim (b)		—			—		1,750
	Corporate—loss related to settlement (c)		(79	)		—		—
	Corporate—other		(374	)		—		100
	All Other—gain on insurance claim (d)		571			—		—
	All Other—other		67			—		—
	TOTAL	$	835		$	9,251	$	(15,870	)

Notes_Payable_Tables

Notes Payable (Tables)	12 Months Ended
	Jul. 31, 2014
Notes Payable [Abstract]	'
Schedule of Notes Payable	'
	31-Jul	2014			2013
	(in thousands)
	$11.0 million secured term loan due September 2015 (a)	$	6,624		$	6,880
	$1.2 million note due June 2012 (b)		—			279
	Total notes payable		6,624			7,159
	Less current portion		(271	)		(535	)
	Notes payable—long term portion	$	6,353		$	6,624
Schedule of Future Principal Payments of Notes Payable	'
	(in thousands)
	Year ending July 31:
	2015	$	271
	2016		6353
	2017		—
	2018		—
	2019		—
	Thereafter		—
	Total notes payable	$	6,624

Accrued_Expenses_Tables

Accrued Expenses (Tables)	12 Months Ended
	Jul. 31, 2014
Accrued Expenses [Abstract]	'
Summary of Accrued Expenses	'
	31-Jul	2014		2013
	(in thousands)
	Carrier minutes termination	$	53,280	$	50,687
	Carrier network connectivity, toll-free and 800 services		7,896		11,462
	Regulatory fees and taxes		43,293		38,602
	Legal settlements		1,615		11,784
	Compensation costs		15,612		12,836
	Legal and professional fees		4,708		6,026
	Other		16,124		14,035
	TOTAL	$	142,528	$	145,432

Other_Expense_Income_Net_Table

Other (Expense) Income, Net (Tables)	12 Months Ended
	Jul. 31, 2014
Other (Expense) Income, Net [Abstract]	'
Schedule of Other Income (Expense), Net	'
	Year ended July 31	2014			2013			2012
	(in thousands)
	Foreign currency transaction (losses) gains	$	(5,883	)	$	2,538		$	(2,859	)
	Gain on investments		1,218			2,664			1,172
	Gain on modification and early termination of note payable		—			238			—
	Gain on sales of buildings and other assets		—			11			197
	Other		(35	)		(68	)		(277	)
	TOTAL	$	(4,700	)	$	5,383		$	(1,767	)

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Jul. 31, 2014
Income Tax Disclosure [Abstract]	'
Schedule of Income (loss) from Continuing Operations Before Income Taxes	'
	Year ended July 31	2014			2013			2012
	(in thousands)
	Domestic	$	21,624		$	44,355		$	9,573
	Foreign		3,368			(10,405	)		(21,421	)
	INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	$	24,992		$	33,950		$	(11,848	)
Schedule of Deferred Income Tax Assets	'
	31-Jul	2014			2013
	(in thousands)
	Deferred income tax assets:
	Bad debt reserve	$	2,188		$	2,812
	Accrued expenses		2,937			7,096
	Stock options and restricted stock		2,131			2,786
	Charitable contributions		1,230			2,415
	Impairment		25,745			25,566
	Depreciation		7,566			989
	Unrealized gain		163			507
	Net operating loss		126,093			144,001
	Credits		3,123			2,845
	Total deferred income tax assets		171,176			189,017
	Valuation allowance		(151,975	)		(167,328	)
	DEFERRED INCOME TAX ASSETS, NET	$	19,201		$	21,689
Schedule of (Provision for) Benefit from Income Taxes	'
	Year ended July 31	2014			2013			2012
	(in thousands)
	Current:
	Federal	$	(279	)	$	671		$	1,652
	State and local		—			148			2,503
	Foreign		(1,177	)		(1,431	)		1,741
			(1,456	)		(612	)		5,896
	Deferred:
	Federal		(6,461	)		(14,181	)		36,166
	State and local		(175	)		(1,079	)		764
	Foreign		4,110			—			(44	)
			(2,526	)		(15,260	)		36,886
	(PROVISION FOR) BENEFIT FROM INCOME TAXES	$	(3,982	)	$	(15,872	)	$	42,782
Schedule of Statutory Income Tax Rate and Income Taxes Provided	'
	Year ended July 31	2014			2013			2012
	(in thousands)
	U.S. federal income tax at statutory rate	$	(8,747	)	$	(11,883	)	$	4,147
	Valuation allowance		4,110			—			41,961
	Foreign tax rate differential		961			(5,073	)		(5,800	)
	Nondeductible expenses		761			714			(26	)
	Other		7			50			—
	Prior year tax (expense) benefit		(960	)		921			2,500
	State and local income tax, net of federal benefit		(114	)		(601	)		—
	(PROVISION FOR) BENEFIT FROM INCOME TAXES	$	(3,982	)	$	(15,872	)	$	42,782
Schedule of Change in Valuation Allowance	'
	Year ended July 31	Balance at			Additions			Deductions			Balance at
	(in thousands)	beginning of			charged to						end of year
		year			costs and
					expenses
	2014
	Reserves deducted from deferred income taxes, net:
	Valuation allowance	$	167,328		$	—		$	(15,353	)	$	151,975
	2013
	Reserves deducted from deferred income taxes, net:
	Valuation allowance	$	204,977		$	462		$	(38,111	)	$	167,328
	2012
	Reserves deducted from deferred income taxes, net:
	Valuation allowance	$	206,669		$	41,925		$	(43,617	)	$	204,977
Summary of Change in Balance of Unrecognized Income Tax Benefits	'
	Year ended July 31	2014			2013			2012
	(in thousands)
	Balance at beginning of year	$	356		$	—		$	3,754
	Additions based on tax positions related to the current year		—			—			—
	Additions for tax positions of prior years		—			356			—
	Reductions for tax positions of prior years		—			—			—
	Settlements		(356	)		—			(3,754	)
	Lapses of statutes of limitations		—			—			—
	Balance at end of year	$	—		$	356		$	—

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Jul. 31, 2014
Stock-Based Compensation [Abstract]	'
Schedule of Risk Free Rate Based on U.S. Treasury Yield Curve Effect at Time of Grant	'
	Year ended July 31	2012
	ASSUMPTIONS
	Average risk-free interest rate		1.46	%
	Expected dividend yield		4.6	%
	Expected volatility		66.8	%
	Expected term		6.6 years
Summary of Stock Option Activity	'
		Number of			Weighted-		Weighted-		Aggregate
		Options			Average		Average		Intrinsic Value
		(in thousands)			Exercise		Remaining		(in thousands)
					Price		Contractual
							Term
							(in years)
	Outstanding at July 31, 2013		642		$	14.22
	Granted		—			—
	Exercised		(29	)		13.45
	Cancelled / Forfeited		(2	)		21.38
	OUTSTANDING AT JULY 31, 2014		611		$	14.24		6.6	$	1,285
	EXERCISABLE AT JULY 31, 2014		438		$	15.63		5.2	$	444
Summary of Grants of Restricted Shares of Class B Common Stock	'
	(in thousands)	Number of			Weighted-
		Non-vested			Average Grant-
		Shares			Date Fair
					Value
	Non-vested shares at July 31, 2013		2,013		$	6.11
	Granted		183			19.71
	Vested		(1,649	)		5.29
	Forfeited		(7	)		10.17
	NON-VESTED SHARES AT JULY 31, 2014		540		$	13

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Jul. 31, 2014
Accumulated Other Comprehensive Income Loss [Abstract]	'
Schedule of Accumulated Balances for Each Classification of Other Comprehensive Income (Loss)	'
	in thousands)	Unrealized			Foreign			Accumulated
		gain (loss) on			currency			other
		available-for-			translation			comprehensive
		sale securities						income (loss)
	Balance at July 31, 2011	$	(4	)	$	3,031		$	3,027
	Genie Spin-Off		—			(438	)		(438	)
	Other comprehensive loss attributable to IDT Corporation		4			(2,391	)		(2,387	)
	Balance at July 31, 2012		—			202			202
	Other comprehensive income attributable to IDT Corporation		—			2,139			2,139
	Balance at July 31, 2013		—			2,341			2,341
	Other comprehensive income attributable to IDT Corporation		(8	)		1,335			1,327
	BALANCE AT JULY 31, 2014	$	(8	)	$	3,676		$	3,668

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Jul. 31, 2014
Legal Proceedings and Commitments And Contingencies Disclosure [Abstract]	'
Summary of Future Minimum Payments for Operating Leases	'
	(in thousands)
	Year ending July 31:
	2015	$	2,801
	2016		1,383
	2017		1,146
	2018		934
	2019		812
	Thereafter		235
	Total payments	$	7,311
Summary of Restricted Cash and Cash Equivalents	'
	July 31	2014		2013
	(in thousands)
	Restricted cash and cash equivalents—short-term
	Letters of credit related	$	665	$	3,189
	IDT Financial Services customer deposits		64,415		31,076
	Other		626		723
	Total short-term		65,706		34,988
	Restricted cash and cash equivalents—long-term
	Letters of credit related		2,763		2,767
	Total restricted cash and cash equivalents	$	68,469	$	37,755

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Jul. 31, 2014
Related Party Transactions [Abstract]	'
Summary of Changes in Estimated Liability to Stright Path Included in Other Current Liabilities	'
	Year ended July 31	2014
	(in thousands)
	Balance at beginning of year	$	931
	Additional liability		1,930
	Payments		(1,001	)
	Balance at end of year	$	1, 860

Business_Segment_Information_T

Business Segment Information (Tables)	12 Months Ended
	Jul. 31, 2014
Business Segment Information [Abstract]	'
Summary of Operating Results of Business Segments	'
	(in thousands)	Telecom			Consumer			Zedge			All Other			Corporate			Total
		Platform			Phone
		Services			Services
	Year ended July 31, 2014
	Revenues	$	1,615,570		$	11,023		$	6,535		$	18,413		$	—		$	1,651,541
	Income (loss) from operations		45,062			1,797			314			(2,049	)		(15,284	)		29,840
	Depreciation and amortization		13,776			—			967			1,545			30			16,318
	Year ended July 31, 2013
	Revenues	$	1,588,071		$	14,514		$	5,811		$	12,221		$	—		$	1,620,617
	Income (loss) from operations		48,661			1,824			340			(7,433	)		(14,001	)		29,391
	Depreciation and amortization		12,342			1			798			1,673			96			14,910
	Impairment of building and improvements		—			—			—			4,359			—			4,359
	Year ended July 31, 2012
	Revenues	$	1,477,762		$	19,307		$	3,793		$	5,421		$	—		$	1,506,283
	Income (loss) from operations		5,910			4,062			(248	)		(3,668	)		(13,152	)		(7,096	)
	Depreciation and amortization		14,215			9			652			1,512			260			16,648
Revenue from External Customers by Geographic Areas	'
	Year ended July 31	2014			2013			2012
	Revenue from customers located outside of the United States		30	%		23	%		29	%
	Revenue from customers located in the United Kingdom		19	%		13	%		14	%
Long-Lived Assets and Total Assets by Geographic Areas	'
	(in thousands)	United			Foreign			Total
		States			Countries
	31-Jul-14
	Long-lived assets, net	$	79,281		$	2,479		$	81,760
	Total assets		284,249			196,682			480,931
	31-Jul-13
	Long-lived assets, net	$	77,580		$	3,162		$	80,742
	Total assets		294,337			141,070			435,407
	31-Jul-12
	Long-lived assets, net	$	81,668		$	3,899		$	85,567
	Total assets		310,209			140,905			451,114

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Jul. 31, 2014
Selected Quarterly Financial Data [Abstract]	'
Summary of Selected Quarterly Financial Data	'
	Quarter Ended							Income			Net income			Income (loss) per share						Income (loss) per share
								(loss)			(loss)			—basic						—diluted
	(in thousands, except per share data)	Revenues		Direct cost		Income		from			attributable			From			Net			From			Net
				of revenues		from		continuing			to IDT			continuing			income			continuing			income
						operations		operations			Corporation			operations			(loss)			operations			(loss)
	2014:00:00
	October 31	$	420,670	$	350,319	$	7,283	$	4,050		$	3,523		$	0.17		$	0.17		$	0.15		$	0.15
	January 31		406,423		335,258		7,574		2,973			2,535			0.12			0.12			0.11			0.11
	30-Apr		403,761		332,376		9,170		5,599			5,017			0.22			0.22			0.22			0.22
	31-Jul		420,687		349,313		5,813		8,388			7,709			0.34			0.34			0.33			0.33
	TOTAL	$	1,651,541	$	1,367,266	$	29,840	$	21,010		$	18,784		$	0.85		$	0.85		$	0.82		$	0.82
	2013:00:00
	October 31	$	400,117	$	335,251	$	6,684	$	5,620		$	3,614		$	0.24		$	0.17		$	0.23		$	0.16
	31-Jan		411,456		344,486		5,655		3,908			2,953			0.16			0.14			0.15			0.13
	April 30(a)		396,935		331,163		15,687		10,082			8,691			0.46			0.42			0.43			0.39
	July 31(b)		412,109		344,673		1,365		(1,532	)		(3,651	)		(0.09	)		(0.17	)		(0.09	)		(0.17	)
	TOTAL	$	1,620,617	$	1,355,573	$	29,391	$	18,078		$	11,607		$	0.77		$	0.56		$	0.72		$	0.52

Description_of_Business_and_Su3

Description of Business and Summary of Significant Accounting Policies - Summary of Weighted-Average Number of Shares used in Calculation of Basic and Diluted Earnings Per Share (Detail)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Summary of Weighted-Average Number of Shares used in Calculation of Basic and Diluted Earnings Per Share [Abstract]	'	'	'
Basic weighted-average number of shares	22,009	20,876	20,717
Stock options	92	9	'
Non-vested restricted Class B common stock	836	1,430	1,343
Diluted weighted-average number of shares	22,937	22,315	22,060

Description_of_Business_and_Su4

Description of Business and Summary of Significant Accounting Policies - Summary of Outstanding Stock Options Excluded from Calculation of Diluted Earnings Per Share (Detail)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Earnings Per Share [Abstract]	'	'	'
Shares excluded from the calculation of diluted earnings per share	70	611	619

Description_of_Business_and_Su5

Description of Business and Summary of Significant Accounting Policies - Summary of Change in Allowance for Doubtful Accounts (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Receivables [Abstract]	'		'		'
Allowance for doubtful accounts, Balance at beginning of year	$13,079		$13,044		$15,364
Allowance for doubtful accounts, Additions charged to costs and expenses	500		2,743		2,098
Allowance for doubtful accounts, Deductions	-2,072	[1]	-2,708	[1]	-4,418	[1]
Allowance for doubtful accounts, Balance at end of year	$11,507		$13,079		$13,044
[1]	Primarily uncollectible accounts written off, net of recoveries.

Description_of_Business_and_Su6

Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)

12 Months Ended

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Jul. 31, 2013

Jul. 31, 2012

Jul. 31, 2011

Jul. 31, 2013

Jul. 31, 2013

Jul. 31, 2013

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Segment

Reclassification [Member]

Reclassification [Member]

Reclassification [Member]

Customer Lists [Member]

Trademarks [Member]

Technology and domain names [Member]

Equipment [Member]

Building [Member]

Computer Software [Member]

Furniture and Fixtures [Member]

Internal-use Software [Member]

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of reportable segments

3

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments accounted for using the equity method

$9,400,000

$8,100,000

'

'

'

'

'

'

'

'

'

'

'

'

Investments accounted for using the cost method

1,800,000

1,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Estimated useful lives of Long-Lived assets

'

'

'

'

'

'

'

'

'

'5

'

'2

'5

'

Estimated useful lives of Long-Lived assets

'

'

'

'

'

'

'

'

'

'7

'40

'3

'7

'Excess of one year

Estimated useful lives of Long-Lived assets

'

'

'

'

'

'

'

'

'

'20

'

'5

'10

'

Amortization period

'

'

'

'

'

'

'15 years

'5 years

'3 years

'

'

'

'

'

Advertising expense

17,200,000

13,100,000

17,000,000

'

'

'

'

'

'

'

'

'

'

'

Amortization expense related to capitalized software

7,600,000

6,300,000

5,800,000

'

'

'

'

'

'

'

'

'

'

'

Unamortized capitalized internal use software costs

13,200,000

10,200,000

'

'

'

'

'

'

'

'

'

'

'

'

USF charges

600,000

800,000

1,100,000

'

'

'

'

'

'

'

'

'

'

'

Percentage of consolidated revenues not exceeded by one single customer

10.00%

10.00%

10.00%

'

'

'

'

'

'

'

'

'

'

'

Percentage of consolidated revenues from continuing operations

12.00%

10.00%

8.10%

'

'

'

'

'

'

'

'

'

'

'

Percentage of gross trade accounts receivable from customers

22.10%

16.60%

'

'

'

'

'

'

'

'

'

'

'

'

Restricted cash and cash equivalents-long-term

2,763,000

2,767,000

'

4,600,000

'

'

'

'

'

'

'

'

'

'

Restricted cash and cash equivalents

$25,292,000

$23,006,000

$7,733,000

$2,100,000

$2,000,000

$8,700,000

'

'

'

'

'

'

'

'

Discontinued_Operations_Summar

Discontinued Operations - Summary Financial Data of Discontinued Operations (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Revenues	'	$1,130	$46,349
(Loss) income before income taxes	'	-4,621	7,471
Net (loss) income	'	-4,634	5,851
Straight Path [Member]	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Revenues	'	1,130	553
(Loss) income before income taxes	'	-4,621	4,862
Net (loss) income	'	-4,634	4,836
Genie [Member]	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Revenues	'	'	45,796
(Loss) income before income taxes	'	'	2,609
Net (loss) income	'	'	$1,015

Discontinued_Operations_Additi

Discontinued Operations - Additional Information (Detail) (USD $)	1 Months Ended			1 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Oct. 28, 2011	Oct. 28, 2011	Oct. 28, 2011	Sep. 30, 2011	Aug. 30, 2011	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013
	Genie Energy [Member]	IDT Energy [Member]	Genie Oil and Gas [Member]	IDT Entertainment [Member]	IDT Entertainment [Member]	Straight Path Spectrum, Inc. [Member]	Straight Path IP Group, Inc. [Member]	Straight Path Communications, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'	'	'	'
Ownership percentage at the time of spin-off	99.30%	100.00%	0.92%	'	'	100.00%	84.50%	'
Description of shares issued in spin-off transaction	'Each of the Company's stockholders received one share of Genie Class A common stock for every share of the Company's Class A common stock and one share of Genie Class B common stock for every share of the Company's Class B common stock held of record as of the close of business on October 21, 2011.	'	'	'	'	'	'	'Each of the Company's stockholders received one share of Straight Path Class A common stock for every two shares of the Company's Class A common stock and one share of Straight Path Class B common stock for every two shares of the Company's Class B common stock held of record date as of the close of business on July 25, 2013
Discontinued operations amount funded to spin-off	$106	'	'	'	'	'	'	$15
Payment to Liberty Media in connection with IDT Entertainment	'	'	'	'	3.5	'	'	'
Period to receive additional consideration from Liberty Media Corporation	'	'	'	'	'5 years	'	'	'
Gain (loss) recorded from prior period adjustments	'	'	'	$2	'	'	'	'

Marketable_Securities_Summary_

Marketable Securities - Summary of Marketable Securities (Detail) (USD $)	Jul. 31, 2014		Jul. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost	$12,881		$9,684
Gross Unrealized Gains	1		'
Gross Unrealized Losses	-9		'
Fair Value	12,873		9,684
Certificates of Deposit [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost	10,375	[1]	8,786	[1]
Gross Unrealized Gains	'	[1]	'	[1]
Gross Unrealized Losses	'	[1]	'	[1]
Fair Value	10,375	[1]	8,786	[1]
Equity Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost	31		'
Gross Unrealized Gains	'		'
Gross Unrealized Losses	-9		'
Fair Value	22		'
Municipal Bonds [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost	2,475		898
Gross Unrealized Gains	1		'
Gross Unrealized Losses	'		'
Fair Value	$2,476		$898
[1]	Each of the Company's certificates of deposit has a CUSIP, was purchased in the secondary market through a broker and may be sold in the secondary market.

Marketable_Securities_Summary_1

Marketable Securities - Summary of Available-for-Sale Securities (Detail) (USD $)	Jul. 31, 2014
In Thousands, unless otherwise specified
Marketable Securities [Abstract]	'
Within one year	$12,851
After one year through five years	'
After five years through ten years	'
After ten years	'
TOTAL	$12,851

Marketable_Securities_Addition

Marketable Securities - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Marketable Securities [Abstract]	'	'	'
Proceeds from maturities of available-for-sale securities	$17.30	$1.70	'
Gross realized gains and gross realized losses	'	'	'
Loss for other than temporary decline in market value	$0.10	'	'

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities	$12,873	$9,684
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities	12,873	9,684
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities	'	'
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities	12,873	9,684
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale securities	'	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Millions, unless otherwise specified
Fair Value Assets Liabilities Quantitative Information [Line Items]	'	'
Investments in hedge funds	$9.50	$8.30
Carrying value of investments	1.8	1.5
Other Current Assets [Member]	'	'
Fair Value Assets Liabilities Quantitative Information [Line Items]	'	'
Investments in hedge funds	0.1	0.1
Long-term Investments [Member]	'	'
Fair Value Assets Liabilities Quantitative Information [Line Items]	'	'
Investments in hedge funds	$9.40	$8.20

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
Property Plant And Equipment [Abstract]	'	'
Equipment	$438,899	$436,127
Land and buildings	53,895	51,294
Computer software	116,775	105,449
Leasehold improvements	42,190	45,141
Furniture and fixtures	6,249	6,187
Property, plant and equipment, gross	658,008	644,198
Less accumulated depreciation and amortization	-576,248	-563,456
Property, plant and equipment, net	$81,760	$80,742

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Property Plant And Equipment [Abstract]	'	'	'
Impairment charge for building and improvements	'	$4,359,000	'
Carrying value of the land, building and improvements	37,700,000	37,700,000	'
Depreciation and amortization expense	$15,700,000	$14,300,000	$15,900,000

Goodwill_and_Other_Intangibles2

Goodwill and Other Intangibles - Schedule of Change in Carrying Amount of Goodwill by Operating Segment (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013
Indefinite-lived Intangible Assets [Line Items]	'	'
Beginning balance	$14,807	$14,614
Foreign currency translation adjustments	23	193
Ending balance	14,830	14,807
Telecom Platform Services [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Beginning balance	11,600	11,407
Foreign currency translation adjustments	23	193
Ending balance	11,623	11,600
Zedge [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Beginning balance	3,207	3,207
Foreign currency translation adjustments	'	'
Ending balance	$3,207	$3,207

Goodwill_and_Other_Intangibles3

Goodwill and Other Intangibles - Schedule of Other Intangible Assets (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013
Indefinite-lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period	'5 years 8 months 12 days	'6 years
Gross Carrying Amount	$4,532	$5,273
Accumulated Amortization	-2,790	-3,883
Net Balance	1,742	1,390
Intellectual Property [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period	'4 years 8 months 12 days	'4 years 8 months 12 days
Gross Carrying Amount	670	2,119
Accumulated Amortization	-335	-1,715
Net Balance	335	404
Customer Lists [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period	'6 years 6 months	'6 years 9 months 18 days
Gross Carrying Amount	3,154	3,154
Accumulated Amortization	-2,387	-2,168
Net Balance	767	986
Technology and domain names [Member]	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'
Weighted Average Amortization Period	'3 years	'
Gross Carrying Amount	708	'
Accumulated Amortization	-68	'
Net Balance	$640	'

Goodwill_and_Other_Intangibles4

Goodwill and Other Intangibles - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Goodwill and Other Intangibles [Abstract]	'	'	'
Amortization expense	$0.60	$0.60	$0.70
Amortization expense of intangible assets year one	0.5	'	'
Amortization expense of intangible assets year two	0.4	'	'
Amortization expense of intangible assets year three	0.3	'	'
Amortization expense of intangible assets year four	0.1	'	'
Amortization expense of intangible assets year five	$0.10	'	'

Other_Operating_Gains_Losses_N2

Other Operating Gains (Losses), Net - Summary of Other Operating Gains (Losses), Net by Business Segment (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2013	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Other Operating Gains, Net [Abstract]	'	'		'		'
Telecom Platform Services-gains (losses) related to legal matters, net	'	$650		$9,251		($6,698)
Telecom Platform Services-loss on settlement of litigation	9,600	'	[1]	'	[1]	-11,022	[1]
Telecom Platform Services-gain on settlement of claim	'	'	[2]	'	[2]	1,750	[2]
Corporate-loss related to settlement	'	-79	[3]	'	[3]	'	[3]
Corporate-other	'	-374		'		100
All Other-gain on insurance claim	'	571	[4]	'	[4]	'	[4]
All Other-other	'	67		'		'
TOTAL	'	$835		$9,251		($15,870)
[1]	On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.
[2]	On January 17, 2012, the Company received $1.8 million from Broadstripe, LLC in settlement of the Company's claim stemming from Broadstripe, LLC's rejection of its telephony services agreements with the Company upon the confirmation of Broadstripe, LLC's bankruptcy plan and closing of its bankruptcy sale.
[3]	In fiscal 2014, the Company incurred a loss of $0.1 million in connection with the June 2013 settlement of outstanding claims and disputes with the former Chief Executive Officer of Straight Path Spectrum, Inc. and his related parties.
[4]	In fiscal 2014, the Company received proceeds from insurance of $0.6 million related to water damage to portions of the Company's building and improvements at 520 Broad Street, Newark, New Jersey. The damage occurred in a prior period. The Company recorded a gain of $0.6 million from this insurance claim.

Other_Operating_Gains_Losses_N3

Other Operating Gains (Losses), Net - Summary of Other Operating Gains (Losses), Net by Business Segment (Parenthetical) (Detail) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 17, 2012	Oct. 13, 2011	Apr. 30, 2013	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Other Operating Gains Loss Net Textual [Abstract]	'	'	'	'		'		'
Payment for settlement of disputes to T-Mobile	'	$10,000,000	'	'		'		'
Payment received on bankruptcy settlement	1,800,000	'	'	'		'		'
Legal fees incurred with T-Mobile	'	'	'	'		'		1,000,000
Proceeds from insurance	'	'	'	571,000		'		'
Loss on settlement of outstanding claims and disputes	'	'	9,600,000	'	[1]	'	[1]	-11,022,000	[1]
NEW JERSEY	'	'	'	'		'		'
Other Operating Gains Loss Net Textual [Abstract]	'	'	'	'		'		'
Gain on insurance claim	'	'	'	600,000		'		'
Proceeds from insurance	'	'	'	600,000		'		'
Former Chief Executive Officer of Straight Path Spectrum, Inc [Member]	'	'	'	'		'		'
Other Operating Gains Loss Net Textual [Abstract]	'	'	'	'		'		'
Loss on settlement of outstanding claims and disputes	'	'	'	$100,000		'		'
[1]	On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.

Revolving_Credit_Loan_Payable_

Revolving Credit Loan Payable - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended		1 Months Ended			12 Months Ended
	Jul. 12, 2012	Jul. 31, 2014	Jul. 31, 2013	Aug. 31, 2014	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 12, 2012
				Subsequent Event [Member]	Line of Credit [Member]	Line of Credit [Member]	July 30, 2012 [Member]	Prime Rate [Member]
								BasisPoint
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'
Maximum principal amount of credit agreement	$25,000,000	'	'	'	'	'	'	'
Interest rate description	'	'	'	'	'	'	'Interest per annum, at the option of IDT Telecom, at either (a) the U.S. Prime Rate less 125 basis points, or (b) the LIBOR rate adjusted by the Regulation D maximum reserve requirement plus 150 basis points	'
U.S Prime Rate basis points	'	'	'	'	'	'	'	125
Revolving credit loan payable	'	13,000,000	21,062,000	'	13,000,000	21,100,000	'	'
Interest rate of credit agreement	'	1.65%	1.69%	'	'	'	'	'
Average percentage of commitment fee per annum	0.38%	'	'	'	'	'	'	'
Line of credit facility, convenant compliance	'	'IDT Telecom is required to comply with various affirmative and negative covenants as well as maintain certain financial targets and ratios during the term of the line of credit, including IDT Telecom may not pay any dividend on its capital stock and IDT Telecom's aggregate loans and advances to affiliates or subsidiaries may not exceed $90.0 million.	'	'	'	'	'	'
Maximum amount of investments in and advances to affiliates, at fair value	90,000,000	'	'	'	'	'	'	'
Repayments of credit agreement	'	'	'	13,000,000	'	'	'	'
Aggregate loans and advances to affiliates and subsidiaries	'	$73,700,000	$46,400,000	'	'	'	'	'

Notes_Payable_Schedule_of_Note

Notes Payable - Schedule of Notes Payable (Detail) (USD $)	Jul. 31, 2014		Jul. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'		'
Notes payable	$6,624		$7,159
Less current portion	-271		-535
Notes payable-long term portion	6,353		6,624
Notes Due June 2012 [Member]	'		'
Debt Instrument [Line Items]	'		'
Notes payable	'	[1]	279	[1]
Secured Term Loan Due September 2015 [Member]	'		'
Debt Instrument [Line Items]	'		'
Secured term loan	$6,624	[2]	$6,880	[2]
[1]	On June 24, 2009, the Company issued a promissory note in the principal amount of $1.2 million in connection with the acquisition of the 49% interest in Union Telecard Alliance, LLC that it did not own. The note bears interest at 0.76% per annum. The principal and interest are payable in thirty six equal, monthly installments that began on July 24, 2009 with the last payment on June 24, 2012. The Company has not made any payments since November 2011 due to disputes with the seller.
[2]	The loan bears interest at the rate of 5.6% per annum and is payable in monthly installments of principal and interest of $0.1 million, with the last installment of $6.4 million payable on September 1, 2015. The loan is secured by a mortgage on a building in Piscataway, New Jersey.

Notes_Payable_Schedule_of_Note1

Notes Payable - Schedule of Notes Payable (Parenthetical) (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Jul. 31, 2014	Jun. 24, 2009
Notes Due June 2012 [Member]	'	'
Debt Instrument [Line Items]	'	'
Debt instrument face value	$1.20	$1.20
Debt Instruments Maturity Period	'2012	'
Debt instrument stated interest rate percentage	'	0.76%
Percentage of interest acquired	'	49.00%
Secured Term Loan Due September 2015 [Member]	'	'
Debt Instrument [Line Items]	'	'
Debt instrument face value	11	'
Debt Instruments Maturity Period	'2015	'
Debt instrument stated interest rate percentage	5.60%	'
Debt instrument periodic payment	0.1	'
Reduction in the final balloon payment	$6.40	'

Notes_Payable_Schedule_of_Futu

Notes Payable - Schedule of Future Principal Payments of Notes Payable (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
Notes Payable [Abstract]	'	'
2015	$271	'
2016	6,353	'
2017	'	'
2018	'	'
2019	'	'
Thereafter	'	'
Total notes payable	$6,624	$7,159

Accrued_Expenses_Summary_of_Ac

Accrued Expenses - Summary of Accrued Expenses (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
Accrued Expenses [Abstract]	'	'
Carrier minutes termination	$53,280	$50,687
Carrier network connectivity, toll-free and 800 services	7,896	11,462
Regulatory fees and taxes	43,293	38,602
Legal settlements	1,615	11,784
Compensation costs	15,612	12,836
Legal and professional fees	4,708	6,026
Other	16,124	14,035
TOTAL	$142,528	$145,432

Other_Income_Expense_Net_Sched

Other Income (Expense), Net - Schedule of Other Income (Expense), Net (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Other (Expense) Income, Net [Abstract]	'	'	'
Foreign currency transaction (losses) gains	($5,883)	$2,538	($2,859)
Gain on investments	1,218	2,664	1,172
Gain on modification and early termination of loan payable	'	238	'
Gain on sales of buildings and other assets	'	11	197
Other	-35	-68	-277
TOTAL	($4,700)	$5,383	($1,767)

Other_Income_Expense_Net_Addit

Other Income (Expense), Net - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	1-May-13	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Other Income Expense Net [Line Items]	'	'	'	'
Gain on modification and early termination of loan payable	'	'	$238,000	'
Payments to Lender	21,100,000	'	'	'
April 30, 2013 [Member]	'	'	'	'
Other Income Expense Net [Line Items]	'	'	'	'
Gain on modification and early termination of loan payable	'	'	$200,000	'

Income_Taxes_Schedule_of_Incom

Income Taxes - Schedule of Income (loss) from Continuing Operations Before Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'
Domestic	$21,624	$44,355	$9,573
Foreign	3,368	-10,405	-21,421
Income (loss) from continuing operations before income taxes	$24,992	$33,950	($11,848)

Income_Taxes_Schedule_of_Defer

Income Taxes - Schedule of Deferred Income Tax Assets (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
In Thousands, unless otherwise specified
Deferred income tax assets:	'	'	'	'
Bad debt reserve	$2,188	$2,812	'	'
Accrued expenses	2,937	7,096	'	'
Stock options and restricted stock	2,131	2,786	'	'
Charitable contributions	1,230	2,415	'	'
Impairment	25,745	25,566	'	'
Depreciation	7,566	989	'	'
Unrealized gain	163	507	'	'
Net operating loss	126,093	144,001	'	'
Credits	3,123	2,845	'	'
Total deferred income tax assets	171,176	189,017	'	'
Valuation allowance	-151,975	-167,328	-204,977	-206,669
DEFERRED INCOME TAX ASSETS, NET	$19,201	$21,689	'	'

Income_Taxes_Schedule_of_Provi

Income Taxes - Schedule of (Provision for) Benefit from Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Current:	'	'	'
Federal	($279)	$671	$1,652
State and local	'	148	2,503
Foreign	-1,177	-1,431	1,741
Current Income Tax Expense Benefit	-1,456	-612	5,896
Deferred:	'	'	'
Federal	-6,461	-14,181	36,166
State and local	-175	-1,079	764
Foreign	4,110	'	-44
Deferred Income Tax Expense Benefit	-2,526	-15,260	36,886
(PROVISION FOR) BENEFIT FROM INCOME TAXES	($3,982)	($15,872)	$42,782

Income_Taxes_Schedule_of_Statu

Income Taxes - Schedule of Statutory Income Tax Rate and Income Taxes Provided (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'
U.S. federal income tax at statutory rate	($8,747)	($11,883)	$4,147
Valuation allowance	4,110	'	41,961
Foreign tax rate differential	961	-5,073	-5,800
Nondeductible expenses	761	714	-26
Other	7	50	'
Prior year tax (expense) benefit	-960	921	2,500
State and local income tax, net of federal benefit	-114	-601	'
(PROVISION FOR) BENEFIT FROM INCOME TAXES	($3,982)	($15,872)	$42,782

Income_Taxes_Schedule_of_Chang

Income Taxes - Schedule of Change in Valuation Allowance (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'
Valuation allowance - Balance at beginning of year	$167,328	$204,977	$206,669
Valuation allowance - Additions charged to costs and expenses	'	462	41,925
Valuation allowance - Deductions	-15,353	-38,111	-43,617
Valuation allowance - Balance at end of year	$151,975	$167,328	$204,977

Income_Taxes_Summary_of_Change

Income Taxes - Summary of Change in Balance of Unrecognized Income Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'
Balance at beginning of year	$356	'	$3,754
Additions based on tax positions related to the current year	'	'	'
Additions for tax positions of prior years	'	356	'
Reductions for tax positions of prior years	'	'	'
Settlements	-356	'	-3,754
Lapses of statutes of limitations	'	'	'
Balance at end of year	'	$356	'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Tax Contingency [Line Items]	'	'	'
Reversal of portion of the valuation allowance	'	'	$36,900,000
Federal and state net operating loss carryforwards	168,000,000	'	'
Foreign net operating losses	200,000,000	'	'
Benefit from income taxes	3,982,000	15,872,000	-42,782,000
Net operating loss carryforwards expiration date	'2014	'	'
Foreign net operating loss, no expiration	143,000,000	'	'
Foreign net operating loss, expiration in two to ten years	57,000,000	'	'
Losses limited under Internal Revenue Code	7,000,000	'	'
Cumulative undistributed foreign earnings	270,000,000	'	'
Accrued interest included in current income taxes payable	'	'	'
Agreement on certain state tax position	356,000	'	3,754,000
IDT Global [Member]	'	'	'
Income Tax Contingency [Line Items]	'	'	'
Benefit from income taxes	4,100,000	'	'
Net2Phone [Member]	'	'	'
Income Tax Contingency [Line Items]	'	'	'
Net operating losses, Federal	$84,000,000	'	'
Net operating losses expiration description	'Through fiscal 2027	'	'

Equity_Additional_Information_

Equity - Additional Information (Detail) (USD $)

1 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

Aug. 31, 2013

Dec. 31, 2012

Nov. 21, 2012

Nov. 15, 2011

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Oct. 05, 2014

Jul. 31, 2014

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Oct. 05, 2014

Straight Path [Member]

Additional Paid In Capital [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class A Common Stock [Member]

Class A Common Stock [Member]

Class A Common Stock [Member]

Class A Common Stock [Member]

Class A Common Stock [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Schedule Of Stockholders Equity [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Voting rights description

'

'

'

'

'The holders of Class A common stock are entitled to three votes per share and the holders of Class B common stock are entitled to one-tenth of a vote per share.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividend paid per share

'

'

'

'

'

'

'

'

'

'

$0.59

$0.75

$0.66

$0.17

'

$0.59

$0.75

$0.66

$0.17

Date of declared dividend will be paid

'

'

'

'

'

'

'

'

'

27-Oct-14

'

'

'

'

27-Oct-14

'

'

'

'

Aggregate dividends paid

'

'

'

'

$13,600,000

$17,100,000

$15,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Dividends declared, per share

'

'

'

'

'

'

'

'

'

'

'

$0.08

'

'

'

'

$0.08

'

'

Stock repurchase program, shares authorized for repurchase

'

'

'

'

'

'

'

'

'

8,300,000

8,300,000

'

'

'

'

'

'

'

'

Stock repurchased in a fiscal year

'

'

'

'

'

'

'

'

'

'

'

77,843

300,000

'

'

'

'

'

'

Aggregate purchase price of shares repurchased

'

'

'

'

'

'

'

'

'

'

'

800,000

2,600,000

'

'

'

'

'

'

Stock repurchase program, remaining number of shares authorized to be repurchased

'

'

'

'

'

'

'

'

'

5,100,000

5,100,000

'

'

'

'

'

'

'

'

Cash paid to purchase ownership percentage in subsidiary

1,100,000

1,800,000

'

'

1,133,000

1,804,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage increased in subsidiary

2.80%

4.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage in subsidiary

88.40%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash received on sale of Zedge stock to Shaman II L.P

'

'

100,000

100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of ownership before additional acquisition

'

'

11.10%

11.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of ownership after additional acquisition

'

'

11.17%

11.10%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional liability

'

'

'

'

'

'

'

1,700,000

1,600,000

'

'

'

'

'

'

'

'

'

'

Dividends payable

'

'

'

'

'

$1,837,000

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Risk Free Rate Based on U.S. Treasury Yield Curve Effect at Time of Grant (Detail)	12 Months Ended
	Jul. 31, 2012
Stock-Based Compensation [Abstract]	'
Average risk-free interest rate	1.46%
Expected dividend yield	4.60%
Expected volatility	66.80%
Expected term	'6 years 7 months 6 days

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jul. 31, 2014
Stock-Based Compensation [Abstract]	'
Beginning balance, Outstanding	642
Granted	'
Exercised	-29
Cancelled / Forfeited	-2
Ending balance, OUTSTANDING	611
Ending balance, EXERCISABLE	438
Beginning balance, Outstanding, Weighted-Average Exercise Price	$14.22
Granted, Weighted-Average Exercise Price	'
Exercised, Weighted-Average Exercise Price	$13.45
Cancelled / Forfeited, Weighted-Average Exercise Price	$21.38
Ending balance, OUTSTANDING, Weighted-Average Exercise Price	$14.24
Ending balance, EXERCISABLE, Weighted-Average Exercise Price	$15.63
Weighted- Average Remaining Contractual Term, OUTSTANDING	'6 years 7 months 6 days
Weighted- Average Remaining Contractual Term, EXERCISABLE	'5 years 2 months 12 days
Aggregate Intrinsic Value, OUTSTANDING	$1,285
Aggregate Intrinsic Value, EXERCISABLE	$444

StockBased_Compensation_Grants

Stock-Based Compensation - Grants of Restricted Shares of Class B Common Stock (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jul. 31, 2014
Stock-Based Compensation [Abstract]	'
Weighted- Average Grant- Date Fair Value, Beginning balance	$6.11
Weighted- Average Grant- Date Fair Value, Granted	$19.71
Weighted- Average Grant- Date Fair Value, Vested	$5.29
Weighted- Average Grant- Date Fair Value, Forfeited	$10.17
Weighted- Average Grant- Date Fair Value, Ending Balance	$13
Number of Non-vested Shares, Beginning Balance	2,013
Number of Non-vested Shares, Granted	183
Number of Non-vested Shares, Vested	-1,649
Number of Non-vested Shares, Forfeited	-7
Number of Non-vested Shares, Ending Balance	540

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

In Millions, except Share data, unless otherwise specified

Mar. 26, 2012

Mar. 31, 2012

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Sep. 30, 2014

Jul. 31, 2014

Sep. 24, 2012

Jul. 31, 2013

Aug. 31, 2013

Mar. 26, 2012

Nov. 22, 2011

Dec. 31, 2011

Subsequent Event [Member]

Stock Option [Member]

Straight Path IP Group, Inc. [Member]

Straight Path IP Group, Inc. [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Class B Common Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares of common stock reserved for award under 2005 Stock Option and Incentive Plan

'

'

5,300,000

'

'

'

'

'

'

'

'

'

1,100,000

Shares of common stock authorized for award under 2014 Stock Option and Incentive Plan

'

'

'

'

'

500,000

'

'

'

'

'

'

'

Shares of common stock available for future grants

'

'

300,000

'

'

'

'

'

'

'

'

'

'

Stock option awards vesting period

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

Stock option awards contractual term

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

Weighted-average grant date fair value of options granted during the period

'

'

'

'

$4.97

'

'

'

'

'

'

'

'

Total intrinsic value of options exercised during the period

'

'

$0.20

$0.20

'

'

'

'

'

'

'

'

'

Total unrecognized compensation cost

'

'

1.4

'

'

'

'

'

'

'

'

'

'

Total unrecognized compensation cost, Weighted-average period of recognization

'

'

'2 years 2 months 12 days

'

'

'

'

'

'

'

'

'

'

Percentage of reduction in the exercise price

'

'

'

'

'

'

'

'

'

15.29%

'

43.80%

'

Fully vested outstanding options to purchase shares of Class B common stock

'

'

'

'

'

'

'

'

'

32,155

'

500,000

'

Stock option expiration period extended

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

Extension or replacement applied to options to purchase an aggregate shares of Class B common stock

'

'

'

'

'

'

'

'

'

'

600,000

'

'

Stock-based compensation expense

'

0.3

'

'

'

'

'

'

0.7

'

'

'

'

Option holder shared ratably to purchase shares of Class B common stock

'

'

'

'

'

'

'

'

'

'

'

50,000

'

Total unrecognized compensation cost related to non-vested stock-based compensation arrangements

'

'

3.5

'

'

'

'

'

'

'

'

'

'

Total unrecognized compensation cost related to non-vested stock-based compensation arrangements, expected weighted-average period

'

'

'10 months 24 days

'

'

'

'

'

'

'

'

'

'

Total grant date fair value of shares vested

'

'

$8.70

$3.50

$5.70

'

'

'

'

'

'

'

'

Percentage of grant approved by the Board of Directors

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Schedule of Accumulated Balances for Each Classification of Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Beginning balance	$2,341	$202	$3,027
Genie Spin-Off	'	'	-438
Other comprehensive income attributable to IDT Corporation	1,327	2,139	-2,387
Ending balance	3,668	2,341	202
Unrealized Gain (Loss) on Available-for-Sale Securities [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Beginning balance	'	'	-4
Genie Spin-Off	'	'	'
Other comprehensive income attributable to IDT Corporation	-8	'	4
Ending balance	-8	'	'
Foreign Currency Translation [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Beginning balance	2,341	202	3,031
Genie Spin-Off	'	'	-438
Other comprehensive income attributable to IDT Corporation	1,335	2,139	-2,391
Ending balance	$3,676	$2,341	$202

Legal_Proceedings_Additional_I

Legal Proceedings - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Oct. 17, 2013	5-May-04	Aug. 31, 2011	Jul. 31, 2014	Jul. 31, 2013	Mar. 15, 2013
	Patents				Aerotel Ltd [Member]	Aerotel Ltd [Member]
Loss Contingencies [Line Items]	'	'	'	'	'	'
Number of patents	2	'	'	'	'	'
Damages and interest awarded	'	'	$10.10	'	'	'
Interest on damages per annum (Percentage)	'	'	'	'	'	9.00%
Total amount of Final Award damages	'	'	'	'	'	5.4
Accrued litigation expense	'	'	'	1.1	'	'
Term of indefeasible right to use	'	'15 years	'	'	'	'
Payments for legal settlements	'	'	'	'	$5.40	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Future Minimum Payments for Operating Leases (Detail) (USD $)	Jul. 31, 2014
In Thousands, unless otherwise specified
Year ending July 31:	'
2015	$2,801
2016	1,383
2017	1,146
2018	934
2019	812
Thereafter	235
Total payments	$7,311

Commitments_and_Contingencies_2

Commitments and Contingencies - Restricted Cash and Cash Equivalents (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013
In Thousands, unless otherwise specified
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted cash and cash equivalents-short-term	$65,706	$34,988
Restricted cash and cash equivalents-long-term	2,763	2,767
Total restricted cash and cash equivalents	68,469	37,755
Restricted Cash And Cash Equivalents-Short-Term [Member] | Letters of Credit Related [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted cash and cash equivalents-short-term	665	3,189
Restricted Cash And Cash Equivalents-Short-Term [Member] | IDT Financial Services Customer Deposits [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted cash and cash equivalents-short-term	64,415	31,076
Restricted Cash And Cash Equivalents-Short-Term [Member] | Other [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted cash and cash equivalents-short-term	626	723
Restricted Cash And Cash Equivalents-Long-Term [Member] | Letters of Credit Related [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted cash and cash equivalents-long-term	$2,763	$2,767

Commitments_and_Contingencies_3

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Commitments and contingencies (Textual)	'	'	'
Purchase commitment of company	$2,300,000	'	'
Rental expenses under operating leases	6,400,000	5,900,000	4,100,000
Connectivity charges under operating leases	10,400,000	11,800,000	16,300,000
Letters of credit outstanding	3,700,000	'	3,800,000
Letter of credit expires by July 31, 2015	900,000	'	'
Letter of credit expires in August 2015	2,800,000	'	'
Performance bonds outstanding	10,000,000	'	'
Refundable customer deposits	62,685,000	28,663,000	'
Substantially restricted cash and cash equivalents	$12,900,000	$7,800,000	'

Related_Party_Transactions_Sum

Related Party Transactions - Summary of Changes in Estimated Liability to Stright Path Included in Other Current Liabilities (Details) (Straight Path [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jul. 31, 2014
Straight Path [Member]	'
Estimated liability to stright path included in other current liabilities	'
Balance at beginning of year	$931
Additional liability	1,930
Payments	-1,001
Balance at end of year	$1,860

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (USD $)	1 Months Ended		6 Months Ended	12 Months Ended
	Oct. 31, 2012	Aug. 31, 2009	Oct. 31, 2012	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Related Party Transaction [Line Items]	'	'	'	'	'	'
Amount billed for electricity supplied and natural gas	'	'	'	$16,000	$21,000	$500,000
Number of years office rented	'	'2 years	'	'	'	'
Annual rent payment	69,025	100,000	34,512	'	'	'
Construction cost to build out space	'	100,000	'	'	'	'
Lease and build out cost payment	'	300,000	'	'	'	'
Lease expiration date	'	30-Apr-12	'	'	'	'
Lease period	'1 year	'	'	'	'	'
Lease renewal period	'1 year	'	'	'	'	'
Outstanding net loan receivable from employees	'	'	'	200,000	200,000	'
Straight Path [Member]	'	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'	'
Reduction of selling, general and administrative expense	'	'	'	800,000	'	'
Receivable from subsidiaries included in other current assets	'	'	'	29,000	'	'
Jonas Media Group [Member]	'	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'	'
Receivable from subsidiaries included in other current assets	'	'	'	4,000	6,000	'
Rent received for office space, connectivity and other services	'	'	'	18,000	27,000	29,000
IGM Brokerage Corp [Member]	'	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'	'
Commissions and fees from payment by company	'	'	'	20,000	15,000	19,000
Insurance Payment made by the Company	'	'	'	'	'	200,000
Genie and Subsidiaries [Member]	'	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'	'
Reduction of selling, general and administrative expense	'	'	'	3,100,000	3,800,000	2,700,000
Receivable from subsidiaries included in other current assets	'	'	'	500,000	600,000	'
Mason and Company [Member]	'	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'	'
Commissions and fees from payment by company	'	'	'	$18,000	$24,000	$20,000

Defined_Contribution_Plans_Add

Defined Contribution Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Defined Contribution Plans [Abstract]	'	'	'
Maximum percentage of participants contribution	20.00%	'	'
Percentage of discretionary matching contributions	50.00%	'	'
Defined benefit plan compensation	6.00%	'	'
Company's cost for contributions to the Plan	$1.10	$1.10	$0.90
Number of shares issed for contribution plan	72,281	51,861	92,843

Business_Segment_Information_S

Business Segment Information - Summary of Operating Results of Business Segments (Detail) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Jul. 31, 2014

Apr. 30, 2014

Jan. 31, 2014

Oct. 31, 2013

Jul. 31, 2013

Apr. 30, 2013

Jan. 31, 2013

Oct. 31, 2012

Jul. 31, 2014

Jul. 31, 2013

Jul. 31, 2012

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

$420,687

$403,761

$406,423

$420,670

$412,109

[1]

$396,935

[2]

$411,456

$400,117

$1,651,541

$1,620,617

$1,506,283

Income (loss) from operations

5,813

9,170

7,574

7,283

1,365

[1]

15,687

[2]

5,655

6,684

29,840

29,391

-7,096

Depreciation and amortization

'

'

'

'

'

'

'

'

16,318

14,910

16,648

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

4,359

'

Operating Segments [Member] | Telecom Platform Services [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

'

'

'

'

'

'

'

'

1,615,570

1,588,071

1,477,762

Income (loss) from operations

'

'

'

'

'

'

'

'

45,062

48,661

5,910

Depreciation and amortization

'

'

'

'

'

'

'

'

13,776

12,342

14,215

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

'

'

Operating Segments [Member] | Consumer Phone Services [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

'

'

'

'

'

'

'

'

11,023

14,514

19,307

Income (loss) from operations

'

'

'

'

'

'

'

'

1,797

1,824

4,062

Depreciation and amortization

'

'

'

'

'

'

'

'

'

1

9

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

'

'

Operating Segments [Member] | Zedge [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

'

'

'

'

'

'

'

'

6,535

5,811

3,793

Income (loss) from operations

'

'

'

'

'

'

'

'

314

340

-248

Depreciation and amortization

'

'

'

'

'

'

'

'

967

798

652

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

'

'

Operating Segments [Member] | All Other [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

'

'

'

'

'

'

'

'

18,413

12,221

5,421

Income (loss) from operations

'

'

'

'

'

'

'

'

-2,049

-7,433

-3,668

Depreciation and amortization

'

'

'

'

'

'

'

'

1,545

1,673

1,512

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

4,359

'

Operating Segments [Member] | Corporate [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

REVENUES

'

'

'

'

'

'

'

'

'

'

'

Income (loss) from operations

'

'

'

'

'

'

'

'

-15,284

-14,001

-13,152

Depreciation and amortization

'

'

'

'

'

'

'

'

30

96

260

Impairment of building and improvements

'

'

'

'

'

'

'

'

'

'

'

[1]

Included in income from operations was a charge for impairment of building and improvements of $4.4 million.

[2]

Included in income from operations was other operating gains of $9.6 million related to legal matters

Business_Segment_Information_R

Business Segment Information - Revenue from External Customers by Geographic Areas (Detail)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Outside of the United States[Member]	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue from external customers	30.00%	23.00%	29.00%
United Kingdom [Member]	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue from external customers	19.00%	13.00%	14.00%

Business_Segment_Information_L

Business Segment Information - Long-Lived Assets and Total Assets by Geographic Areas (Detail) (USD $)	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
In Thousands, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Long-lived assets, net	$81,760	$80,742	$85,567
Total assets	480,931	435,407	451,114
United States [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Long-lived assets, net	79,281	77,580	81,668
Total assets	284,249	294,337	310,209
Foreign Countries [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Long-lived assets, net	2,479	3,162	3,899
Total assets	$196,682	$141,070	$140,905

Business_Segment_Information_A

Business Segment Information - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
			Segment
Segment Reporting Information [Line Items]	'	'	'		'		'
Number of reportable segments	'	'	3		'		'
Gain from settlement of litigation	'	'	$650,000		$9,251,000		($6,698,000)
Other operating losses	'	'	835,000		9,251,000		-15,870,000
Estimated losses from pending litigation	'	6,500,000	'		'		'
Gain (loss) from settlement of litigation	9,600,000	'	'	[1]	'	[1]	-11,022,000	[1]
Loss on settlement of unrelated claim	'	'	'		'		200,000
Telecom Platform Services [Member]	'	'	'		'		'
Segment Reporting Information [Line Items]	'	'	'		'		'
Gain from settlement of litigation	'	'	'		9,300,000		'
Other operating losses	'	'	'		'		-15,900,000
Estimated losses from pending litigation	'	'	'		'		6,500,000
Broadstripe, LLC [Member]	'	'	'		'		'
Segment Reporting Information [Line Items]	'	'	'		'		'
Gain (loss) from settlement of litigation	'	'	'		'		$1,800,000
[1]	On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data - Summary of Selected Quarterly Financial Data (Detail) (USD $)	3 Months Ended										12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013		Apr. 30, 2013		Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Selected Quarterly Financial Data [Abstract]	'	'	'	'	'		'		'	'	'	'	'
REVENUES	$420,687	$403,761	$406,423	$420,670	$412,109	[1]	$396,935	[2]	$411,456	$400,117	$1,651,541	$1,620,617	$1,506,283
Direct cost of revenues	349,313	332,376	335,258	350,319	344,673	[1]	331,163	[2]	344,486	335,251	1,367,266	1,355,573	1,269,386
Income from operations	5,813	9,170	7,574	7,283	1,365	[1]	15,687	[2]	5,655	6,684	29,840	29,391	-7,096
Income (loss) from continuing operations	8,388	5,599	2,973	4,050	-1,532	[1]	10,082	[2]	3,908	5,620	21,010	18,078	30,934
Net income (loss) attributable to IDT corporation	$7,709	$5,017	$2,535	$3,523	($3,651)	[1]	$8,691	[2]	$2,953	$3,614	$18,784	$11,607	$38,648
Income (loss) per share-basic, From continuing operations	$0.34	$0.22	$0.12	$0.17	($0.09)	[1]	$0.46	[2]	$0.16	$0.24	$0.85	$0.85	$1.45
Income (loss) per share-basic, Net income (loss)	$0.34	$0.22	$0.12	$0.17	($0.17)	[1]	$0.42	[2]	$0.14	$0.17	$0.85	$0.85	$1.87
Income (loss) per share-diluted, From continuing operations	$0.33	$0.22	$0.11	$0.15	($0.09)	[1]	$0.43	[2]	$0.15	$0.23	$0.82	$0.82	$1.36
Income (loss) per share-diluted, Net income (loss)	$0.33	$0.22	$0.11	$0.15	($0.17)	[1]	$0.39	[2]	$0.13	$0.16	$0.82	$0.82	$1.75
[1]	Included in income from operations was a charge for impairment of building and improvements of $4.4 million.
[2]	Included in income from operations was other operating gains of $9.6 million related to legal matters

Selected_Quarterly_Financial_D3

Selected Quarterly Financial Data - Summary of Selected Quarterly Financial Data (Parenthetical) (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2013	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Selected Quarterly Financial Data [Abstract]	'	'		'		'
Other operating gains (loss)	$9,600	'	[1]	'	[1]	($11,022)	[1]
Impairment of building and improvements	'	'		$4,359		'
[1]	On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.

Subsequent_Event_Details

Subsequent Event (Details) (Fabrix Subsidiary [Member], Subsequent Event [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 08, 2014
Fabrix Subsidiary [Member] | Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Common stock sold to Ericsson	$95
Sale of stock to Ericsson in percentage	100.00%
Company owns in Fabrix in percentage	78.00%
Proceeds from divestiture of interest in consolidated subsidiaries	73
Escrow deposit	$13
Unclaimed escrow balance	'18 months