BUSINESS SEGMENTS (External Net Sales from Continuing Operations by Major Product) (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Aug. 31, 2015	[1]	May. 31, 2015	[1]	Feb. 28, 2015	[1]	Nov. 30, 2014	[1]	Aug. 31, 2014	[1]	May. 31, 2014	[1]	Feb. 28, 2014	[1]	Nov. 30, 2013	[1]	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,411,496		$ 1,506,002		$ 1,391,117		$ 1,679,990		$ 1,837,309		$ 1,738,593		$ 1,597,461		$ 1,617,075		$ 5,988,605	$ 6,790,438	$ 6,601,070
Steel products
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	4,084,092	4,500,093	4,033,286
Industrial materials
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	566,323	659,251	928,472
Nonferrous scrap
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	536,856	639,961	682,611
Ferrous scrap
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	428,192	659,578	646,263
Construction materials
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	220,232	199,154	189,046
Nonferrous products
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	10,443	8,761	5,674
Other
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	$ 142,467	$ 123,640	$ 115,718

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