Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Concentration Risk [Line Items]
Severance expense	$ 8,200,000	$ 21,500,000	$ 12,500,000
Accrued severance liability	5,400,000	3,100,000
Deposit for letter of credit	31,100,000	26,900,000
Currency transaction gains (losses) recorded in selling, general and administrative expenses	7,100,000	(2,700,000)	(5,300,000)
Fabrication [Member]
Segment Reporting Information [Line Items]
Unbilled revenue related to fabrication projects	13,200,000	14,300,000
Secured Accounts Receivable [Member]
Concentration Risk [Line Items]
Accounts receivable secured by credit insurance and/or letters of credit	$ 690,000,000	$ 520,000,000