Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Noncontrolling Interests	IDT Corp Additional Paid-In Capital	IDT Corp Treasury Stock	IDT Corp Accumulated Other Comprehensive Loss	IDT Corp Accumulated Deficit	IDT Corp Class A Common Stock	IDT Corp Class B Common Stock
Beginning Balance at Jul. 31, 2017	$ 154,557	$ 8,823	$ 394,462	$ (83,304)	$ (2,343)	$ (163,370)	$ 33	$ 256
Dividends declared	(11,677)					(11,677)
Restricted Class B common stock purchased from employees	(61)			(61)
Transfer of right to receive equity to Howard S. Jonas	(40)	(40)
Consolidation of Lipomedix Pharmaceuticals Ltd.	558	558
Stock-based compensation	2,842		2,842
Distributions to noncontrolling interests	(1,023)	(1,023)
Rafael Spin-Off	(114,919)	(8,653)	(103,996)		(2,270)
Other comprehensive loss/income	16				16
Net income (loss)	(3,336)	698				(4,034)
Ending Balance at Apr. 30, 2018	26,917	363	293,308	(83,365)	(4,597)	(179,081)	33	256
Beginning Balance at Jan. 31, 2018	146,360	9,094	396,259	(83,365)	(2,531)	(173,386)	33	256
Dividends declared	(2,237)					(2,237)
Stock-based compensation	1,045		1,045
Distributions to noncontrolling interests	(306)	(306)
Rafael Spin-Off	(114,919)	(8,653)	(103,996)		(2,270)
Other comprehensive loss/income	204				204
Net income (loss)	(3,230)	228				(3,458)
Ending Balance at Apr. 30, 2018	26,917	363	293,308	(83,365)	(4,597)	(179,081)	33	256
Beginning Balance at Jul. 31, 2018	31,303	639	294,047	(85,597)	(4,972)	(173,103)	33	256
Adjustment from the adoption of change in revenue recognition (see Note 2)/in accounting for equity investments (see Note 8) | ASU 2014-09	9,064					9,064
Adjustment from the adoption of change in revenue recognition (see Note 2)/in accounting for equity investments (see Note 8) | ASU 2016-01	1,173				33	1,140
BALANCE at Jul. 31, 2018	41,540	639	294,047	(85,597)	(4,939)	(162,899)	33	256
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	14,772		(22,968)	37,740
Stock-based compensation	1,212		1,212
Distributions to noncontrolling interests	(1,187)	(1,187)
Other comprehensive loss/income	474				474
Net income (loss)	3,498	888				2,610
Ending Balance at Apr. 30, 2019	56,427	340	272,291	(51,739)	(4,465)	(160,289)	33	256
Beginning Balance at Jan. 31, 2019	52,410	503	271,959	(51,727)	(4,455)	(164,159)	33	256
Restricted Class B common stock purchased from employees	(12)			(12)
Stock-based compensation	332		332
Distributions to noncontrolling interests	(450)	(450)
Other comprehensive loss/income	(10)				(10)
Net income (loss)	4,157	287				3,870
Ending Balance at Apr. 30, 2019	$ 56,427	$ 340	$ 272,291	$ (51,739)	$ (4,465)	$ (160,289)	$ 33	$ 256