Description of Business and Summary of Significant Accounting Policies - Summary of Change in Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Receivables [Abstract]
Allowance for doubtful accounts, Balance at beginning of year	$ 13,079		$ 13,044		$ 15,364
Allowance for doubtful accounts, Additions charged to costs and expenses	500		2,743		2,098
Allowance for doubtful accounts, Deductions	(2,072)	[1]	(2,708)	[1]	(4,418)	[1]
Allowance for doubtful accounts, Balance at end of year	$ 11,507		$ 13,079		$ 13,044

[1] Primarily uncollectible accounts written off, net of recoveries.