Fair Value Measures (Assets And Liabilities Measured At Fair Value) (Details) (USD $) In Thousands	Aug. 31, 2011	Aug. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate money market funds	$ 161,168	$ 172,218
Derivative instruments	897	879
Total assets measured at fair value	162,065	173,097
Derivative instruments	0	1,220
Total liabilities measured at fair value	0	1,220
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate money market funds	161,168	172,218
Derivative instruments	0	0
Total assets measured at fair value	161,168	172,218
Derivative instruments	0	0
Total liabilities measured at fair value	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate money market funds	0	0
Derivative instruments	897	879
Total assets measured at fair value	897	879
Derivative instruments	0	1,220
Total liabilities measured at fair value	0	1,220
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate money market funds	0	0
Derivative instruments	0	0
Total assets measured at fair value	0	0
Derivative instruments	0	0
Total liabilities measured at fair value	$ 0	$ 0