Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Feb. 28, 2013 segments		Feb. 29, 2012	Feb. 28, 2013 segments		Feb. 29, 2012	Aug. 31, 2012
Segment Reporting [Abstract]
Number Of Operating and Reporting Segments	3			3
Segment Reporting Information [Line Items]
Revenue from External Customers	$ 662,210		$ 886,612	$ 1,255,030		$ 1,698,787
Operating income	11,390		17,987	12,604		32,955
Restructuring charges	(1,540)		0	(3,133)		0
Interest expense	(2,354)		(3,472)	(4,371)		(6,743)
Other income (expense), net	(49)		617	271		223
Income before income taxes	8,987		15,132	8,504		26,435
Total Assets	1,807,430			1,807,430			1,763,573
Investments in joint ventures partnerships	16,486			16,486			17,126
Metal Recycling Business [Member]
Segment Reporting Information [Line Items]
Revenues including intercompany	576,191		781,933	1,070,652		1,510,371
Less: Intersegment revenues	(42,461)		(39,986)	(89,717)		(98,700)
Revenue from External Customers	533,730		741,947	980,935		1,411,671
Operating income	14,158		19,952	19,812		33,051
Restructuring charges				(610)
Total Assets	1,699,320	[1]		1,699,320	[1]		1,696,296	[1]
Investments in joint ventures partnerships	16,000			16,000			17,000
Auto Parts Business [Member]
Segment Reporting Information [Line Items]
Revenues including intercompany	78,082		78,232	147,637		162,285
Less: Intersegment revenues	(20,849)		(18,090)	(36,818)		(39,593)
Revenue from External Customers	57,233		60,142	110,819		122,692
Operating income	6,711		8,708	13,075		19,150
Restructuring charges				(211)
Total Assets	350,299			350,299			329,327
Steel Manufacturing Business [Member]
Segment Reporting Information [Line Items]
Revenue from External Customers	71,247		84,523	163,276		164,424
Operating income	1,041		(868)	4,445		349
Total Assets	327,972			327,972			322,398
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income	21,910		27,792	37,332		52,550
Total Assets	2,377,591			2,377,591			2,348,021
Corporate and eliminations [Member]
Segment Reporting Information [Line Items]
Operating income	(8,980)		(9,805)	(21,595)		(19,595)
Total Assets	$ (570,161)			$ (570,161)			$ (584,448)

[1] MRB total assets include $16 million and $17 million as of February 28, 2013 and August 31, 2012, respectively, for investments in joint venture partnerships.