CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	May 31, 2012	Aug. 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 2,850	$ 4,788
Property, plant and equipment, accumulated depreciation	1,521,939	1,363,481
Intangible assets, accumulated amortization	$ 138,121	$ 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	231,512,492	224,653,990
Common stock, shares outstanding	205,473,091	203,416,503
Treasury stock, shares	26,039,401	21,237,487