Business Segments (Details 2) (USD $) In Thousands	3 Months Ended												12 Months Ended
	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2010	Feb. 28, 2010	Nov. 30, 2009	Aug. 31, 2009	May 31, 2009	Feb. 28, 2009	Nov. 30, 2008	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 2,267,620	$ 2,076,564	$ 1,791,766	$ 1,782,480	$ 1,816,247	$ 1,765,154	$ 1,322,443	$ 1,402,258	$ 1,411,449	$ 1,258,237	$ 1,507,460	$ 2,232,230	$ 7,918,430	$ 6,306,102	$ 6,409,376
Steel products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													4,463,203	3,637,631	4,351,569
Industrial materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													1,134,819	913,019	885,333
Nonferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													997,771	702,467	411,490
Ferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													805,067	561,119	260,755
Construction materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													221,633	230,294	288,707
Nonferrous products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													196,641	178,844	150,461
Other [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales													$ 99,296	$ 82,728	$ 61,061