Other Operating Gains (Losses), Net (Details Textual) (USD $)	1 Months Ended		2 Months Ended	3 Months Ended	9 Months Ended
	Jan. 31, 2012	Oct. 31, 2011	Apr. 30, 2012	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012	Oct. 13, 2011
Other Operating Gains (Losses), Net (Textual)
Proceeds from sale of rights in wireless spectrum licenses			$ 6,800,000			$ 6,800,000
Gain on sale of wireless spectrum			5,300,000	5,300,000		5,330,000
Payment received on bankruptcy settlement	1,800,000
Payment for settlement of disputes to T-Mobile		10,000,000
Legal fees incurred with T-Mobile							$ 1,000,000