Business Segments (External Net Sales from Continuing Operations by Major Product) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended															12 Months Ended
	Aug. 31, 2013	May 31, 2013		Feb. 28, 2013		Nov. 30, 2012		Aug. 31, 2012		May 31, 2012		Feb. 29, 2012		Nov. 30, 2011		Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,698,861	$ 1,752,534	[1]	$ 1,688,665	[1]	$ 1,749,515	[1]	$ 1,833,026	[1]	$ 1,957,827	[1]	$ 1,918,049	[1]	$ 1,947,473	[1]	$ 6,889,575	$ 7,656,375	$ 7,666,773
Steel products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																4,318,072	4,699,226	4,412,810
Industrial materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																928,472	1,147,386	1,134,819
Nonferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																682,611	765,349	997,717
Ferrous scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																646,263	763,772	805,067
Construction materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																189,046	177,827	217,741
Nonferrous products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																5,674	2,689	2,573
Other [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																$ 119,437	$ 100,126	$ 96,046

[1] Excludes divisions classified as discontinued operations. See Note 10, Businesses Held for Sale, Discontinued Operations and Dispositions.