CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Aug. 31, 2012	Aug. 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 3,237	$ 4,788
Property, plant and equipment, accumulated depreciation	1,578,266	1,363,481
Intangible assets, accumulated amortization	$ 141,572	$ 128,467
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	232,069,203	224,653,990
Common stock, shares outstanding	206,028,577	203,416,503
Treasury stock, share	26,040,626	21,237,487