Business Segments (External Net Sales From Continuing Operations By Major Product) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,956,744	$ 1,781,650	$ 3,943,564	$ 3,556,742
Steel Products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	1,101,612	954,881	2,257,452	2,004,631
Industrial Materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	345,998	278,062	666,500	491,908
Ferrous Scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	205,083	180,968	412,429	341,387
Nonferrous Scrap [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	200,740	254,199	395,038	474,471
Construction Materials [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	37,973	43,325	82,467	99,654
Nonferrous Products [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	39,577	45,913	79,690	90,980
Other Product [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 25,761	$ 24,302	$ 49,988	$ 53,711