BUSINESS SEGMENTS (Summary of Certain Financial Information from Continuing Operations by Reportable Segment) (Details) - USD ($) $ in Thousands		3 Months Ended																12 Months Ended
		Aug. 31, 2016		May 31, 2016	[1]	Feb. 29, 2016	[1]	Nov. 30, 2015	[1]	Aug. 31, 2015		May 31, 2015	[1]	Feb. 28, 2015	[1]	Nov. 30, 2014	[1]	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Segment Reporting Information [Line Items]
Net sales		$ 1,208,580	[1]	$ 1,227,390		$ 1,019,697		$ 1,154,859		$ 1,411,496	[1]	$ 1,506,002		$ 1,391,117		$ 1,679,990		$ 4,610,526	$ 5,988,605	$ 6,790,438
Interest expense																		62,231	77,760	77,037
Capital expenditures																		163,332	119,580	101,749
Impairment of assets																		40,028	9,839	3,305
Total assets		3,130,869								3,439,951								3,130,869	3,439,951
Continuing Operations
Segment Reporting Information [Line Items]
Net sales																		4,610,526	5,988,605	6,790,438
Americas Recycling
Segment Reporting Information [Line Items]
Net sales																		594,275	887,068	1,176,907
Americas Mills
Segment Reporting Information [Line Items]
Net sales																		839,432	1,048,063	1,198,249
Americas Fabrication
Segment Reporting Information [Line Items]
Net sales																		1,479,125	1,612,084	1,523,573
International Mill
Segment Reporting Information [Line Items]
Net sales																		516,643	626,219	822,224
International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales																		1,173,969	1,814,319	2,055,202
Corporate
Segment Reporting Information [Line Items]
Net sales																		7,082	852	14,283
Eliminations
Segment Reporting Information [Line Items]
Net sales																		0	0	0
Segments | Continuing Operations
Segment Reporting Information [Line Items]
Net sales																		4,610,526	5,988,605	6,790,438
Adjusted operating profit (loss)																		149,108	225,282	245,829
Interest expense	[2]																	62,231	77,760	77,037
Capital expenditures	[3]																	163,255	115,800	101,149
Depreciation and amortization																		126,940	132,503	134,222
Impairment of assets																		40,028	9,839	3,305
Total assets	[4]	3,124,082								3,408,426								3,124,082	3,408,426	3,682,568
Segments | Americas Recycling
Segment Reporting Information [Line Items]
Net sales																		705,754	1,022,621	1,367,070
Adjusted operating profit (loss)																		(61,284)	(29,157)	(5,687)
Interest expense	[2]																	2,210	2,628	2,700
Capital expenditures	[3]																	4,891	12,811	16,771
Depreciation and amortization																		17,919	17,460	14,832
Impairment of assets																		38,900	7,494	1,592
Total assets	[4]	188,873								261,676								188,873	261,676	316,967
Segments | Americas Mills
Segment Reporting Information [Line Items]
Net sales																		1,498,848	1,841,812	1,991,334
Adjusted operating profit (loss)																		209,751	255,507	256,536
Interest expense	[2]																	1,942	4,207	7,059
Capital expenditures	[3]																	110,375	67,203	31,781
Depreciation and amortization																		47,924	46,780	45,392
Impairment of assets																		0	0	0
Total assets	[4]	798,481								738,669								798,481	738,669	762,549
Segments | Americas Fabrication
Segment Reporting Information [Line Items]
Net sales																		1,489,455	1,624,238	1,537,485
Adjusted operating profit (loss)																		68,602	22,424	6,440
Interest expense	[2]																	8,356	8,864	10,222
Capital expenditures	[3]																	14,958	14,883	13,798
Depreciation and amortization																		13,620	17,509	19,192
Impairment of assets																		0	1,585	0
Total assets	[4]	659,165								713,860								659,165	713,860	734,500
Segments | International Mill
Segment Reporting Information [Line Items]
Net sales																		517,186	626,251	823,193
Adjusted operating profit (loss)																		28,892	17,555	30,632
Interest expense	[2]																	2,608	2,620	4,608
Capital expenditures	[3]																	27,155	15,413	30,770
Depreciation and amortization																		25,902	28,087	32,209
Impairment of assets																		208	124	567
Total assets	[4]	372,492								403,706								372,492	403,706	466,449
Segments | International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales																		1,189,596	1,897,617	2,120,537
Adjusted operating profit (loss)																		(7,087)	35,376	30,557
Interest expense	[2]																	3,524	9,096	6,924
Capital expenditures	[3]																	289	296	1,122
Depreciation and amortization																		1,302	1,928	2,328
Impairment of assets																		726	623	172
Total assets	[4]	564,068								798,914								564,068	798,914	822,679
Segments | Corporate
Segment Reporting Information [Line Items]
Net sales																		7,082	852	14,283
Adjusted operating profit (loss)																		(95,085)	(77,832)	(72,347)
Interest expense	[2]																	43,591	50,345	45,524
Capital expenditures	[3]																	5,587	5,194	6,907
Depreciation and amortization																		20,273	20,739	20,269
Impairment of assets																		194	13	974
Total assets	[4]	1,034,053								1,044,178								1,034,053	1,044,178	1,048,517
Segments | Eliminations
Segment Reporting Information [Line Items]
Net sales																		(797,395)	(1,024,786)	(1,063,464)
Adjusted operating profit (loss)																		5,319	1,409	(302)
Interest expense	[2]																	0	0	0
Capital expenditures	[3]																	0	0	0
Depreciation and amortization																		0	0	0
Impairment of assets																		0	0	0
Total assets	[4]	$ (493,050)								$ (552,577)								(493,050)	(552,577)	(469,093)
Intersegment | Continuing Operations
Segment Reporting Information [Line Items]
Net sales																		0	0	0
Intersegment | Americas Recycling
Segment Reporting Information [Line Items]
Net sales																		111,479	135,553	190,163
Intersegment | Americas Mills
Segment Reporting Information [Line Items]
Net sales																		659,416	793,749	793,085
Intersegment | Americas Fabrication
Segment Reporting Information [Line Items]
Net sales																		10,330	12,154	13,912
Intersegment | International Mill
Segment Reporting Information [Line Items]
Net sales																		543	32	969
Intersegment | International Marketing and Distribution
Segment Reporting Information [Line Items]
Net sales																		15,627	83,298	65,335
Intersegment | Corporate
Segment Reporting Information [Line Items]
Net sales																		0	0	0
Intersegment | Eliminations
Segment Reporting Information [Line Items]
Net sales																		$ (797,395)	$ (1,024,786)	$ (1,063,464)

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

[2] Includes intercompany interest expense (income) in the segments and is all eliminated within Corporate.

[3] Excludes capital expenditures from discontinued operations that were immaterial for the years ended August 31, 2016, 2015 and 2014.

[4] Excludes total assets from discontinued operations of $6.8 million at August 31, 2016, $31.5 million at August 31, 2015 and $151.1 million at August 31, 2014.