Selected Quarterly Financial Data - Summary of Selected Quarterly Financial Data (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Apr. 30, 2013	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Selected Quarterly Financial Data [Abstract]
Other operating gains (loss)	$ 9,600		[1]		[1]	$ (11,022)	[1]
Impairment of building and improvements				$ 4,359

[1] On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.