Basis of Presentation (Details) In Thousands, unless otherwise specified							3 Months Ended
	Oct. 31, 2014 Common Stock [Member] Common Class A [Member]	Jul. 31, 2014 Common Stock [Member] Common Class A [Member]	Jul. 31, 2013 Common Stock [Member] Common Class A [Member]	Oct. 31, 2014 Common Stock [Member] Common Class B [Member]	Jul. 31, 2014 Common Stock [Member] Common Class B [Member]	Jul. 31, 2013 Common Stock [Member] Common Class B [Member]	Oct. 31, 2014 Straight Path Spectrum [Member]	Oct. 31, 2014 Straight Path IP [Member]	Jul. 31, 2013 Idt [Member] Common Class B [Member]
Basis of Presentation (Textual)
Ownership in Straight Path Spectrum							100.00%	84.50%
Common stock shares distributed	787	787	787	11,197	11,013	10,700
Common stock, shares outstanding	787	787		11,161	11,013				21,400