BUSINESS SEGMENTS (Summary of Certain Financial Information from Continuing Operations by Reportable Segment) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		May 31, 2016	May 31, 2015	May 31, 2016	May 31, 2015	Aug. 31, 2015
Segment Reporting Information [Line Items]
Net sales		$ 1,227,390	$ 1,506,002	$ 3,401,946	$ 4,577,109
Adjusted operating profit (loss)		60,940	82,168	146,969	187,044
Total assets		3,110,686		3,110,686		$ 3,445,588
Continuing Operations
Segment Reporting Information [Line Items]
Net sales		1,227,390	1,506,002	3,401,946	4,577,109
Adjusted operating profit (loss)		60,940	82,168	146,969	187,044
Total assets	[1]	3,107,760		3,107,760		3,414,063
Americas Recycling
Segment Reporting Information [Line Items]
Net sales		156,352	194,081	430,829	691,382
Adjusted operating profit (loss)		(1,978)	(3,651)	(16,171)	(15,260)
Total assets	[1]	229,557		229,557		261,676
Americas Mills
Segment Reporting Information [Line Items]
Net sales		227,736	244,632	634,926	796,218
Adjusted operating profit (loss)		54,976	63,320	164,739	195,438
Total assets	[1]	758,336		758,336		738,669
Americas Fabrication
Segment Reporting Information [Line Items]
Net sales		382,607	415,763	1,096,049	1,165,679
Adjusted operating profit (loss)		22,794	13,720	58,964	3,770
Total assets	[1]	656,055		656,055		713,860
International Mill
Segment Reporting Information [Line Items]
Net sales		141,043	156,286	368,949	472,364
Adjusted operating profit (loss)		5,467	6,146	10,189	11,188
Total assets	[1]	360,734		360,734		403,706
International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales		315,067	494,639	867,084	1,447,316
Adjusted operating profit (loss)		892	25,615	(3,570)	49,669
Total assets	[1]	591,105		591,105		798,914
Corporate
Segment Reporting Information [Line Items]
Net sales		4,585	601	4,109	4,150
Adjusted operating profit (loss)		(22,542)	(19,502)	(69,415)	(55,513)
Total assets	[1]	1,015,991		1,015,991		1,049,815
Eliminations
Segment Reporting Information [Line Items]
Net sales		0	0	0	0
Adjusted operating profit (loss)		1,331	(3,480)	2,233	(2,248)
Total assets	[1]	(504,018)		(504,018)		$ (552,577)
Segments | Continuing Operations
Segment Reporting Information [Line Items]
Net sales		1,227,390	1,506,002	3,401,946	4,577,109
Segments | Americas Recycling
Segment Reporting Information [Line Items]
Net sales		182,477	225,096	510,030	800,234
Segments | Americas Mills
Segment Reporting Information [Line Items]
Net sales		396,481	446,821	1,117,442	1,400,517
Segments | Americas Fabrication
Segment Reporting Information [Line Items]
Net sales		385,080	417,895	1,103,538	1,174,793
Segments | International Mill
Segment Reporting Information [Line Items]
Net sales		141,438	156,318	369,344	472,396
Segments | International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales		319,604	518,244	879,517	1,521,288
Segments | Corporate
Segment Reporting Information [Line Items]
Net sales		4,585	601	4,109	4,150
Segments | Eliminations
Segment Reporting Information [Line Items]
Net sales		(202,275)	(258,973)	(582,034)	(796,269)
Intersegment | Continuing Operations
Segment Reporting Information [Line Items]
Net sales		0	0	0	0
Intersegment | Americas Recycling
Segment Reporting Information [Line Items]
Net sales		26,125	31,015	79,201	108,852
Intersegment | Americas Mills
Segment Reporting Information [Line Items]
Net sales		168,745	202,189	482,516	604,299
Intersegment | Americas Fabrication
Segment Reporting Information [Line Items]
Net sales		2,473	2,132	7,489	9,114
Intersegment | International Mill
Segment Reporting Information [Line Items]
Net sales		395	32	395	32
Intersegment | International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales		4,537	23,605	12,433	73,972
Intersegment | Corporate
Segment Reporting Information [Line Items]
Net sales		0	0	0	0
Intersegment | Eliminations
Segment Reporting Information [Line Items]
Net sales		$ (202,275)	$ (258,973)	$ (582,034)	$ (796,269)

[1] Excludes total assets from discontinued operations of $2.9 million at May 31, 2016 and $31.5 million at August 31, 2015.