Discontinued Operations (Details Textual) (USD $)	12 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Severance expense	$ 8,200,000	$ 21,500,000	$ 12,500,000
Inventory valuation adjustments	25,503,000	53,203,000	127,056,000
Joist Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of majority of joist and deck assets	1,900,000
Deck Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of majority of joist and deck assets		2,600,000
LIFO income from liquidation of LIFO reserve		1,900,000
Joist and Deck Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Severance expense	0	11,700,000
Impairment charges of property, plant and equipment		26,800,000
Impairment Charges of Intangible Assets		4,500,000
Inventory valuation adjustments		$ 7,400,000
Number of remaining asset locations	5