Business Segments (External Net Sales from Continuing Operations by Major Product) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2012	Nov. 30, 2011
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,789,226	$ 1,986,820
Steel products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	1,104,597	1,155,840
Industrial materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	243,431	320,502
Nonferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	181,333	194,298
Ferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	151,017	207,346
Construction materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	48,148	44,494
Nonferrous products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	39,122	40,113
Other [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 21,578	$ 24,227