Goodwill (Details) (USD $)	3 Months Ended
	Nov. 30, 2012
Goodwill [Line Items]
Accumulated goodwill impairment charges	$ 0
Goodwill [Roll Forward]
Goodwill, beginning of period	635,491,000
Purchase accounting adjustments	(2,000)
Foreign currency translation adjustment	(1,038,000)
Goodwill, end of period	634,451,000
Metal Recycling Business [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	471,954,000
Purchase accounting adjustments	(2,000)
Foreign currency translation adjustment	(904,000)
Goodwill, end of period	471,048,000
Auto Parts Business [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	163,537,000
Purchase accounting adjustments	0
Foreign currency translation adjustment	(134,000)
Goodwill, end of period	$ 163,403,000