BUSINESS SEGMENTS (External Net Sales from Continuing Operations by Major Product) (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Aug. 31, 2016	[1]	May 31, 2016	[1]	Feb. 29, 2016	[1]	Nov. 30, 2015	[1]	Aug. 31, 2015	[1]	May 31, 2015	[1]	Feb. 28, 2015	[1]	Nov. 30, 2014	[1]	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 1,208,580		$ 1,227,390		$ 1,019,697		$ 1,154,859		$ 1,411,496		$ 1,506,002		$ 1,391,117		$ 1,679,990		$ 4,610,526	$ 5,988,605	$ 6,790,438
Steel products
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	3,156,028	4,084,092	4,500,093
Industrial materials
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	453,714	566,323	659,251
Nonferrous scrap
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	364,690	536,856	639,961
Ferrous scrap
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	287,713	428,192	659,578
Construction materials
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	242,961	220,232	199,154
Nonferrous products
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	13,456	10,443	8,761
Other
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales																	$ 91,964	$ 142,467	$ 123,640

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