Valuation And Qualifying Accounts (Schedule Of Doubtful Accounts And Billing Adjustments) (Details) (USD $) In Thousands	12 Months Ended
	Aug. 31, 2011		Aug. 31, 2010		Aug. 31, 2009
Valuation And Qualifying Accounts [Abstract]
Balance at Beginning of Year	$ 1,862	[1]	$ 1,712	[1]	$ 1,681	[1]
Charged to Expense/ Against Revenue	1,748	[1]	2,903	[1]	2,488	[1]
Write-offs, Net of Recoveries	1,655	[1]	2,753	[1]	2,457	[1]
Balance at End of Year	$ 1,955	[1]	$ 1,862	[1]	$ 1,712	[1]

[1] Additions to the allowance for doubtful accounts are charged to bad debt expense. Additions to the allowance for billing adjustments are charged against revenues.