Fair Value Measurements (Details) (USD $)	3 Months Ended					3 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Aug. 31, 2013	Nov. 30, 2013 Recurring Fair Value Measurement [Member]	Aug. 31, 2013 Recurring Fair Value Measurement [Member]	Nov. 30, 2013 Nonrecurring Fair Value Measurement [Member]	Nov. 30, 2013 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2013 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Recurring Fair Value Measurement [Member]	Nov. 30, 2013 Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] Nonrecurring Fair Value Measurement [Member]	Nov. 30, 2013 Significant Other Observable Inputs (Level 2) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2013 Significant Other Observable Inputs (Level 2) [Member] Recurring Fair Value Measurement [Member]	Nov. 30, 2013 Significant Other Observable Inputs (Level 2) [Member] Nonrecurring Fair Value Measurement [Member]	Nov. 30, 2013 Significant Unobservable Inputs (Level 3) [Member] Recurring Fair Value Measurement [Member]	Aug. 31, 2013 Significant Unobservable Inputs (Level 3) [Member] Recurring Fair Value Measurement [Member]	Nov. 30, 2012 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]	Nov. 30, 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)				$ 635,109,000	$ 732,530,000		$ 635,109,000	$ 732,530,000		$ 0	$ 0		$ 0	$ 0
Auction-rate securities (marketable securities)				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				641,055,000	738,476,000		635,109,000	732,530,000		0	0		5,946,000	5,946,000
Contingent payment (other long-term liabilities)				5,743,000	5,277,000		0	0		0	0		5,743,000	5,277,000	6,000,000	0
Total liabilities at fair value on a recurring basis				5,743,000	5,277,000		0	0		0	0		5,743,000	5,277,000
Carrying value of debt, excluding capital leases	33,913,000		642,400,000
Initial lease obligations						9,951,000			0			0					9,951,000
Losses for period	31,963,000	24,116,000				9,951,000
Liabilities Measured at Fair Value Recurring Basis [Roll Forward]
Balance				5,743,000	5,277,000		0	0		0	0		5,743,000	5,277,000	6,000,000	0
Purchase of noncontrolling interest	0	6,000,000
Change in fair value included in net income	466,000	0
Balance				$ 5,743,000	$ 5,277,000		$ 0	$ 0		$ 0	$ 0		$ 5,743,000	$ 5,277,000	$ 6,000,000	$ 0