Goodwill and Other Intangible Assets (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Finite-Lived Intangible Assets [Line Items]
Impairment charges for goodwill	$ 0	$ 2.8	$ 0
Amortization expense for intangible assets	$ 9.9	$ 11.2	$ 15.5
Favorable land leases [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful lives of the intangible assets	78
Intangible assets excluding favorable land leases [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful lives of the intangible assets	5

Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

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+ Details