Business Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,986,820	$ 1,775,092
Steel products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	1,155,840	1,049,750
Industrial materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	320,502	213,845
Ferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	207,346	160,418
Nonferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	194,298	220,273
Construction materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	44,494	56,329
Nonferrous products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	40,113	45,067
Other [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 24,227	$ 29,410