Basis of Presentation (Details) (Subsequent Event [Member], USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2013	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Subsequent Event [Member]
Basis of Presentation (Textual)
Share exchange ratio under spin off transaction	The Company's stockholders will receive one share of Straight Path Class A common stock for every five shares of the Company's Class A common stock and one share of Straight Path Class B common stock for every five shares of the Company's Class B common stock held on the record date for the spin-off.
Sufficient cash transfer to subsidiary	$ 15
USF charges		$ 0.2	$ 0.3	$ 0.7	$ 0.9