Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2015	Apr. 30, 2014
Statements of Operations [Abstract]
Revenues	$ 2,867us-gaap_Revenues	$ 913us-gaap_Revenues	$ 10,471us-gaap_Revenues	$ 1,493us-gaap_Revenues
Costs and expenses:
Direct cost of revenues	1,315us-gaap_CostOfRevenue	425us-gaap_CostOfRevenue	4,761us-gaap_CostOfRevenue	736us-gaap_CostOfRevenue
Selling, general and administrative	1,353	665	4,061	2,276
Total costs and expenses	2,668us-gaap_CostsAndExpenses	1,090us-gaap_CostsAndExpenses	8,822us-gaap_CostsAndExpenses	3,012us-gaap_CostsAndExpenses
Income (loss) from operations	199us-gaap_OperatingIncomeLoss	(177)us-gaap_OperatingIncomeLoss	1,649us-gaap_OperatingIncomeLoss	(1,519)us-gaap_OperatingIncomeLoss
Other income:
Interest income	9us-gaap_InterestIncomeOther	6us-gaap_InterestIncomeOther	27us-gaap_InterestIncomeOther	13us-gaap_InterestIncomeOther
Other income			23us-gaap_OtherIncome
Income from IDT Corporation payments of liabilities		332strp_IncomeFromPaymentsOfLiabilities		383strp_IncomeFromPaymentsOfLiabilities
Total other income	9us-gaap_InterestAndOtherIncome	338us-gaap_InterestAndOtherIncome	50us-gaap_InterestAndOtherIncome	396us-gaap_InterestAndOtherIncome
Income (loss) before income taxes	208	161	1,699	(1,123)
Provision for (income taxes) income tax benefits	801us-gaap_IncomeTaxExpenseBenefit	(40)us-gaap_IncomeTaxExpenseBenefit	(54)us-gaap_IncomeTaxExpenseBenefit	(40)us-gaap_IncomeTaxExpenseBenefit
Net income (loss)	1,009us-gaap_ProfitLoss	121us-gaap_ProfitLoss	1,645us-gaap_ProfitLoss	(1,163)us-gaap_ProfitLoss
Net (income) loss attributable to noncontrolling interests	(211)	(4)	(418)	163
Net income (loss) attributable to Straight Path Communications Inc.	$ 798us-gaap_NetIncomeLoss	$ 117us-gaap_NetIncomeLoss	$ 1,227us-gaap_NetIncomeLoss	$ (1,000)us-gaap_NetIncomeLoss
Earnings (loss) per share attributable to Straight Path Communications Inc. stockholders:
Basic	$ 0.07us-gaap_EarningsPerShareBasic	$ 0.01us-gaap_EarningsPerShareBasic	$ 0.11us-gaap_EarningsPerShareBasic	$ (0.09)us-gaap_EarningsPerShareBasic
Diluted	$ 0.07us-gaap_EarningsPerShareDiluted	$ 0.01us-gaap_EarningsPerShareDiluted	$ 0.10us-gaap_EarningsPerShareDiluted	$ (0.09)us-gaap_EarningsPerShareDiluted
Weighted-average number of shares used in calculation of earnings (loss) per share:
Basic	11,449	11,339	11,426	10,878
Diluted	11,879	11,649	11,837	10,878

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