Allowance for Uncollectible Accounts Receivables (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at end of period	$ 2,000	$ 2,600
Allowance for uncollectible accounts receivable
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	2,574	3,095	4,423
Additions and adjustments charged to costs and expenses	17,056	1,617	373
Write-offs	(17,636)	(2,138)	(1,701)
Balance at end of period	$ 1,994	$ 2,574	$ 3,095