Fair Value Measurements (Details) (USD $)	3 Months Ended		9 Months Ended					9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012	Nov. 30, 2012	May 31, 2013 Recurring Fair Value Measurement [Member]	Aug. 31, 2012 Recurring Fair Value Measurement [Member]	May 31, 2013 Nonrecurring Fair Value Measurement [Member]	May 31, 2013 Nonrecurring Fair Value Measurement [Member] Lease Abandonment Obligation [Member]	May 31, 2013 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2012 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Recurring Fair Value Measurement [Member]	May 31, 2013 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Nonrecurring Fair Value Measurement [Member]	May 31, 2013 Significant Other Observable Inputs (Level 2) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2012 Significant Other Observable Inputs (Level 2) [Member] Recurring Fair Value Measurement [Member]	May 31, 2013 Significant Other Observable Inputs (Level 2) [Member] Nonrecurring Fair Value Measurement [Member]	May 31, 2013 Significant Unobservable Inputs (Level 3) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2012 Significant Unobservable Inputs (Level 3) [Member] Recurring Fair Value Measurement [Member]	May 31, 2013 Significant Unobservable Inputs (Level 3) [Member] Nonrecurring Fair Value Measurement [Member]
Assets and liabilities measured on a recurring and nonrecurring basis [Line Items]
Money market funds (cash and cash equivalents)						$ 893,758,000	$ 629,166,000			$ 893,758,000	$ 629,166,000		$ 0	$ 0		$ 0	$ 0
Auction-rate securities (other assets)						5,946,000	5,946,000			0	0		0	0		5,946,000	5,946,000
Total assets at fair value on a recurring basis						899,704,000	635,112,000			893,758,000	629,166,000		0	0		5,946,000	5,946,000
Contingent payment (other long-term liabilities)	6,022,000		6,022,000		6,000,000	6,022,000				0			0			6,022,000
Total liabilities at fair value on a recurring basis						6,022,000				0			0			6,022,000
Initial lease obligations								57,596,000				0			0			57,596,000
Losses for period	63,103,000	7,577,000	131,295,000	29,287,000					57,596,000
Total liabilities at fair value on a nonrecurring basis								57,596,000				0			0			57,596,000
Total liabilities at fair value on a nonrecurring basis, losses								57,596,000
Liabilities Measured at Fair Value Recurring Basis [Roll Forward]
Balance			0		6,000,000	6,022,000				0			0			6,022,000
Purchase of noncontrolling interest			6,000,000
Change in fair value included in net income			22,000
Balance	$ 6,022,000		$ 6,022,000		$ 6,000,000	$ 6,022,000				$ 0			$ 0			$ 6,022,000