Notes Payable and Long-Term Debt Outstanding (Parenthetical) (Detail) (USD $)	Feb. 28, 2013		Aug. 31, 2012		May 02, 2012	Feb. 28, 2013 Variable Interest Entity	May 02, 2012 Maximum	Feb. 28, 2013 7.750% Senior Notes Due 2016	Aug. 31, 2012 7.750% Senior Notes Due 2016	Feb. 28, 2011 7.750% Senior Notes Due 2016	Feb. 28, 2013 8.250% Senior Notes Due 2018	Aug. 31, 2012 8.250% Senior Notes Due 2018	Aug. 31, 2007 8.250% Senior Notes Due 2018	Feb. 28, 2013 5.625% Senior Notes Due 2020	Aug. 31, 2012 5.625% Senior Notes Due 2020	Feb. 28, 2013 4.700% Senior Notes due 2022	Aug. 31, 2012 4.700% Senior Notes due 2022
Debt Instrument [Line Items]
Senior Notes, stated interest rate								7.75%	7.75%	7.75%	8.25%	8.25%	8.25%	5.625%	5.625%	4.70%	4.70%
Senior Notes, maturity year								2016	2016		2018	2018		2020	2020	2022	2022
VIE credit capacity					$ 60,000,000
Lease agreement period							5 years
Total assets	8,247,641,000		7,803,141,000			50,900,000
Notes receivable						49,600,000
Total liabilities	6,069,651,000		5,695,806,000			50,400,000
Debt obligation utilized	$ 51,134,000	[1]	$ 56,036,000	[1]		$ 50,300,000

[1] On May 2, 2012, the Company entered into a master lease agreement with a variable interest entity (the "VIE") whereby it sells to and subsequently leases back from the VIE up to $60.0 million in certain machinery and equipment for a period of up to five years. In connection with this transaction, the Company holds a variable interest in the VIE, which was designed to hold debt obligations payable to third-party creditors. The proceeds from such debt obligations are utilized to finance the purchase of the machinery and equipment that is then leased by the Company. The Company is the primary beneficiary of the VIE as it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Therefore, the Company consolidates the financial statements of the VIE and eliminates all intercompany transactions. At February 28, 2013, the VIE had approximately $50.9 million of total assets, of which approximately $49.6 million was comprised of a note receivable due from the Company, and approximately $50.4 million of total liabilities, of which approximately $50.3 million were debt obligations to the third-party creditors (as the VIE has utilized approximately $50.3 million of the $60.0 million debt obligation capacity). The third-party creditors have recourse to the Company's general credit only in the event that the Company defaults on its obligations under the terms of the master lease agreement. In addition, the assets held by the VIE can be used only to settle the obligations of the VIE.