Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Nov. 30, 2011	Aug. 31, 2011
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 40,855,000
Reserves Established (Released), Net	(300,000)
Payments	(22,000)
Ending balance	40,533,000
Short-Term	2,971,000	2,983,000
Long-Term	37,562,000	37,872,000
Metal Recycling Business [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	25,655,000
Reserves Established (Released), Net	(300,000)
Payments	(22,000)
Ending balance	25,333,000
Short-Term	2,417,000
Long-Term	22,916,000
Auto Parts Business [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	15,200,000
Reserves Established (Released), Net	0
Payments	0
Ending balance	15,200,000
Short-Term	554,000
Long-Term	14,646,000
Steel Manufacturing Business [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Ending balance	0
Annual production capacity (in tons)	950
Portland Harbor Superfund Site [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance		1,000,000
Ending balance	1,000,000	1,000,000
Other Metals Recycling Business Sites [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Ending balance	$ 24,000,000
Minimum [Member] | Portland Harbor Superfund Site [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Number Of Potentially Responsible Parties	80