CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	May 31, 2017	Aug. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 14,267	$ 11,094
Property, plant and equipment, accumulated depreciation	3,024,934	2,721,972
Intangible assets, accumulated amortization	$ 259,444	$ 232,618
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	252,656,479	249,763,699
Common stock, shares outstanding	179,463,376	186,998,472
Treasury stock, shares	73,193,103	62,765,227