Business Segments (Summary of Certain Financial Information from Continuing Operations by Reportable Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended																12 Months Ended
	Aug. 31, 2013		May 31, 2013		Feb. 28, 2013		Nov. 30, 2012		Aug. 31, 2012		May 31, 2012		Feb. 29, 2012		Nov. 30, 2011		Aug. 31, 2013		Aug. 31, 2012		Aug. 31, 2011
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers	$ 1,698,861		$ 1,752,534	[1]	$ 1,688,665	[1]	$ 1,749,515	[1]	$ 1,833,026	[1]	$ 1,957,827	[1]	$ 1,918,049	[1]	$ 1,947,473	[1]	$ 6,889,575		$ 7,656,375		$ 7,666,773
Adjusted operating profit (loss)																	206,438		240,712		101,058
Capital expenditures																	89,035		113,853		73,215
Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	6,889,575		7,656,375		7,666,773
Intersegment sales																	0		0		0
Net sales																	6,889,575		7,656,375		7,666,773
Adjusted operating profit (loss)																	206,438		240,712		101,058
Interest expense																	69,608	[2]	69,487	[2]	69,814	[2]
Capital expenditures																	87,804	[3]	108,385	[3]	58,911	[3]
Depreciation and amortization																	151,002	[4]	134,442	[4]	175,467	[4]
Total assets	3,444,261	[5]							3,397,870	[5]							3,444,261	[5]	3,397,870	[5]	3,547,266	[5]
Americas Recycling [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	1,225,604		1,418,717		1,692,824
Intersegment sales																	166,145		187,444		136,713
Net sales																	1,391,749		1,606,161		1,829,537
Adjusted operating profit (loss)																	3,170		39,446		43,059
Interest expense																	9	[2]	1,933	[2]	246	[2]
Capital expenditures																	21,261	[3]	40,329	[3]	7,666	[3]
Depreciation and amortization																	13,453	[4]	13,260	[4]	12,860	[4]
Total assets	309,599	[5]							285,136	[5]							309,599	[5]	285,136	[5]	278,120	[5]
Americas Mills [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	1,060,337		1,206,651		1,111,483
Intersegment sales																	759,183		777,070		728,235
Net sales																	1,819,520		1,983,721		1,839,718
Adjusted operating profit (loss)																	204,333		235,918		149,213
Interest expense																	(101)	[2]	12,995	[2]	12,894	[2]
Capital expenditures																	37,216	[3]	38,140	[3]	24,169	[3]
Depreciation and amortization																	42,925	[4]	40,704	[4]	49,264	[4]
Total assets	598,478	[5]							615,070	[5]							598,478	[5]	615,070	[5]	587,053	[5]
Americas Fabrication [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	1,427,785		1,366,944		1,208,823
Intersegment sales																	14,906		14,694		16,899
Net sales																	1,442,691		1,381,638		1,225,722
Adjusted operating profit (loss)																	28,033		(15,697)		(129,141)
Interest expense																	83	[2]	10,809	[2]	9,717	[2]
Capital expenditures																	5,605	[3]	4,389	[3]	2,029	[3]
Depreciation and amortization																	22,302	[4]	22,056	[4]	48,299	[4]
Total assets	631,510	[5]							629,970	[5]							631,510	[5]	629,970	[5]	590,278	[5]
International Mill [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	819,889		955,730		1,043,267
Intersegment sales																	6,155		77,627		2,966
Net sales																	826,044		1,033,357		1,046,233
Adjusted operating profit (loss)																	890		23,044		47,594
Interest expense																	992	[2]	10,090	[2]	18,251	[2]
Capital expenditures																	15,155	[3]	14,016	[3]	14,278	[3]
Depreciation and amortization																	33,238	[4]	32,306	[4]	36,528	[4]
Total assets	487,613	[5]							529,160	[5]							487,613	[5]	529,160	[5]	643,748	[5]
International Marketing and Distribution [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	2,344,128		2,700,300		2,603,494
Intersegment sales																	11,444		27,019		47,405
Net sales																	2,355,572		2,727,319		2,650,899
Adjusted operating profit (loss)																	35,617		47,287		76,337
Interest expense																	4,369	[2]	6,548	[2]	2,173	[2]
Capital expenditures																	1,015	[3]	3,314	[3]	2,873	[3]
Depreciation and amortization																	17,988	[4]	5,821	[4]	4,600	[4]
Total assets	838,413	[5]							870,933	[5]							838,413	[5]	870,933	[5]	990,111	[5]
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	11,832		8,033		6,882
Intersegment sales																	0		0		0
Net sales																	11,832		8,033		6,882
Adjusted operating profit (loss)																	(66,453)		(83,035)		(84,729)
Interest expense																	64,256	[2]	27,112	[2]	26,533	[2]
Capital expenditures																	7,552	[3]	8,197	[3]	7,896	[3]
Depreciation and amortization																	21,096	[4]	20,295	[4]	23,916	[4]
Total assets	1,075,594	[5]							961,654	[5]							1,075,594	[5]	961,654	[5]	1,505,672	[5]
Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales-unaffiliated customers																	0		0		0
Intersegment sales																	(957,833)		(1,083,854)		(932,218)
Net sales																	(957,833)		(1,083,854)		(932,218)
Adjusted operating profit (loss)																	848		(6,251)		(1,275)
Interest expense																	0	[2]	0	[2]	0	[2]
Capital expenditures																	0	[3]	0	[3]	0	[3]
Depreciation and amortization																	0	[4]	0	[4]	0	[4]
Total assets	$ (496,946)	[5]							$ (494,053)	[5]							$ (496,946)	[5]	$ (494,053)	[5]	$ (1,047,716)	[5]

[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] xcludes capital expenditures from discontinued operations of $1.2 million, $5.5 million and $14.3 million for the years ended August 31, 2013, 2012 and 2011, respectively.

[4] Includes asset impairment charges.

[5] xcludes total assets from discontinued operations of $50.5 million at August 31, 2013, $43.4 million at August 31, 2012 and $135.9 million at August 31, 2011.