Revolving Credit Loan Payable - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 12, 2012	Aug. 30, 2013	Oct. 31, 2013	Oct. 31, 2012	Jul. 31, 2013	Jul. 12, 2013
Debt Instrument [Line Items]
Maximum principal amount of credit agreement						$ 25,000,000
Line of credit facility, outstanding			15,000,000		21,062,000
Interest rate of credit agreement			1.668%		1.69%
Average percentage of commitment fee per annum						0.375%
Maximum amount of investments in and advances to affiliates, at fair value	90,000,000
Proceeds from credit agreement			15,000,000
Repayments of credit agreement		21,100,000
Aggregate loans and advances to affiliates and subsidiaries			50,300,000
Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, outstanding			15,000,000		21,100,000
Unused portion of line of credit			$ 25,000,000
July 30, 2012 [Member]
Debt Instrument [Line Items]
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.
Prime Rate [Member]
Debt Instrument [Line Items]
U.S Prime Rate basis points						125