Equity (Details) - USD ($) $ in Thousands				1 Months Ended	12 Months Ended
	Aug. 01, 2016	Jul. 11, 2016	Jan. 16, 2015	Apr. 30, 2015	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Sep. 30, 2014
Equity (Textual)
Common stock issued for exercises of stock options					$ 10	$ 68	$ 17
Treasury stock, shares					40,000	42,000
Sale of treasury stock						$ 65
Treasury Stock [Member]
Equity (Textual)
Treasury stock, shares		2,030			39,963	41,723
Sale of treasury stock		$ 52,476			$ 427,916	$ 480,392
Treasury Stock [Member] | Officer [Member]
Equity (Textual)
Treasury stock, shares			4,105
Sale of treasury stock			$ 65,003
Class A common stock [Member] | Common Stock [Member]
Equity (Textual)
Common stock, voting rights					Class A common stock are entitled to three votes per share.
Class B common stock [Member]
Equity (Textual)
Common stock, voting rights					Class B common stock are entitled to one-tenth of a vote per share.
Issuance of shares, Description					Effective October 17, 2016, the Company will issue to Jonas a grant of 120,000 shares to vest as to 60,000 shares on October 17, 2016 and 20,000 on each of October 18, 2017, October 17, 2018 and October 16, 2019.
Class B common stock [Member] | Dividends [Member]
Equity (Textual)
Dividend declared				$ 5,647,342
Amount paid to minority shareholders				875,338
Unpaid dividends				4,772,004
Class B common stock [Member] | Davidi Jonas [Member]
Equity (Textual)
Common stock issued for compensation, Shares					60,000
Class B common stock [Member] | Officer [Member]
Equity (Textual)
Common stock issued for compensation, Shares					108,000
Class B common stock [Member] | Consultant [Member]
Equity (Textual)
Common stock issued for compensation, Shares					1,250
Class B common stock [Member] | Consultant [Member] | Subsequent Event [Member]
Equity (Textual)
Common stock issued for compensation, Shares	1,250
Class B common stock [Member] | Two Employees [Member]
Equity (Textual)
Common stock issued for compensation, Shares					36,000
Class B common stock [Member] | Non employee directors [Member]
Equity (Textual)
Common stock issued for compensation, Shares					24,000
Class B common stock [Member] | Officers, directors and consultants [Member]
Equity (Textual)
Common stock issued for compensation, Shares							311,226
Class B common stock [Member] | Directors and officers [Member]
Equity (Textual)
Common stock issued for compensation, Shares						264,500
Class B common stock [Member] | Employee [Member]
Equity (Textual)
Common stock issued for compensation, Shares					56,000
Class B common stock [Member] | IDT[Member]
Equity (Textual)
Retirement of common stock issued to former employees of IDT Corporation, Shares							3,550
Number of restricted shares issued to former employees					131	2,200
Class B common stock [Member] | Common Stock [Member]
Equity (Textual)
Common stock issued for compensation, Shares							311,000
Common stock issued for exercises of stock options, Shares					2,000	12,000	3,000
Common stock issued for deferred stock units, Shares						20,000	9,000
Retirement of common stock issued to former employees of IDT Corporation, Shares							(3,000)
Common stock issued or to be issued for compensation, Shares					121,000	265,000
Class B common stock [Member] | Treasury Stock [Member]
Equity (Textual)
Number of shares held in treasury stock value				$ 197,344				$ 348,051
Treasury stock, shares				9,982				35,846
Stock options [Member]
Equity (Textual)
Common stock issued for exercises of stock options, Shares					(1,631)	(12,053)	(3,065)
Stock options [Member] | Class B common stock [Member]
Equity (Textual)
Common stock issued for exercises of stock options, Shares					1,631	12,053	3,065
Common stock issued for exercises of stock options					$ 9,299	$ 68,341	$ 17,000