Consolidated Statements of Equity - USD ($) $ in Thousands	IDT Corporation Stockholders Class A Common Stock	IDT Corporation Stockholders Class B Common Stock	IDT Corporation Stockholders Additional Paid-In Capital	IDT Corporation Stockholders Treasury Stock	IDT Corporation Stockholders Accumulated Other Comprehensive Loss	IDT Corporation Stockholders Accumulated Deficit	Noncontrolling Interests	Total
Beginning Balance at Jul. 31, 2016	$ 33	$ 254	$ 396,243	$ (115,316)	$ (3,744)	$ (153,673)	$ 406	$ 124,203
Beginning Balance, Shares at Jul. 31, 2016	3,272	25,383
Dividends declared						(17,874)		(17,874)
Restricted Class B common stock purchased from employees				(1,838)				(1,838)
Exercise of stock options		$ 1	835					836
Exercise of stock options, Shares		73
Sale of Class B common stock to Howard S. Jonas			(8,920)	33,850				24,930
Sale of interest and rights in Rafael Pharmaceuticals, Inc. to Howard S. Jonas (see Note 4)			(185)				1,185	1,000
Issuance of member interests in CS Pharma Holdings, LLC (see Note 4)			2,750				7,250	10,000
Stock-based compensation		$ 1	3,739					3,740
Stock-based compensation, Shares		105
Distributions to noncontrolling interests							(1,482)	(1,482)
Other comprehensive loss/income					1,401			1,401
Net income for the year ended July 31,						8,177	1,464	9,641
Ending Balance at Jul. 31, 2017	$ 33	$ 256	394,462	(83,304)	(2,343)	(163,370)	8,823	154,557
Ending Balance, Shares at Jul. 31, 2017	3,272	25,561
Dividends declared						(13,941)		(13,941)
Restricted Class B common stock purchased from employees				(362)				(362)
Transfer of right to receive equity to Howard S. Jonas							(40)	(40)
Consolidation of Lipomedix Pharmaceuticals, Inc.							558	558
Repurchases of Class B common stock through repurchase program				(1,931)				(1,931)
Stock-based compensation			3,581					3,581
Stock-based compensation, Shares		33
Distributions to noncontrolling interests							(1,040)	(1,040)
Rafael Spin-Off			(103,996)		(2,270)		(8,653)	(114,919)
Other comprehensive loss/income					(359)			(359)
Net income for the year ended July 31,						4,208	991	5,199
Ending Balance at Jul. 31, 2018	$ 33	$ 256	294,047	(85,597)	(4,972)	(173,103)	639	31,303
Ending Balance, Shares at Jul. 31, 2018	3,272	25,594
Adjustment from the adoption of change in revenue recognition (see Note 2) | ASU 2014-09						9,064		9,064
Adjustment from the adoption of change in revenue recognition (see Note 2) | ASU 2016-01					33	1,140		1,173
BALANCE AT AUGUST 1, 2018 at Jul. 31, 2018	$ 33	$ 256	294,047	(85,597)	(4,939)	(162,899)	639	41,540
BALANCE AT AUGUST 1, 2018, Shares	3,272	25,594
Correction of noncontrolling interests (see Note 18)						2,002	(2,002)
Restricted Class B common stock purchased from employees				(28)				(28)
Repurchases of Class B common stock through repurchase program				(3,854)				(3,854)
Sale of Class B common stock to Howard S. Jonas			(22,968)	37,740				14,772
Stock-based compensation		$ 2	2,234					2,236
Stock-based compensation, Shares		209
Distributions to noncontrolling interests							(1,520)	(1,520)
Other comprehensive loss/income					81			81
Net income for the year ended July 31,						134	196	330
Ending Balance at Jul. 31, 2019	$ 33	$ 258	$ 273,313	$ (51,739)	$ (4,858)	$ (160,763)	$ (2,687)	$ 53,557
Ending Balance, Shares at Jul. 31, 2019	3,272	25,803