Commitments and Contingencies (Details) (USD $)	6 Months Ended		6 Months Ended							0 Months Ended
	Feb. 29, 2012	Aug. 31, 2011	Feb. 29, 2012 Metal Recycling Business [Member]	Feb. 29, 2012 Auto Parts Business [Member]	Feb. 29, 2012 Steel Manufacturing Business [Member] T	Feb. 29, 2012 Portland Harbor Superfund Site [Member]	Feb. 29, 2012 Other Metals Recycling Business Sites [Member]	Feb. 29, 2012 Minimum [Member] Portland Harbor Superfund Site [Member] potentially_responsible_party	Mar. 30, 2012 Subsequent Event [Member] Portland Harbor Superfund Site [Member] alternatives	Mar. 30, 2012 Subsequent Event [Member] Minimum [Member] Portland Harbor Superfund Site [Member]	Mar. 30, 2012 Subsequent Event [Member] Maximum [Member] Portland Harbor Superfund Site [Member]	Mar. 30, 2012 Lower Willamette Group [Member] Subsequent Event [Member] Portland Harbor Superfund Site [Member]	Mar. 30, 2012 Potential Responsible Parties [Member] Subsequent Event [Member] Minimum [Member] Portland Harbor Superfund Site [Member]	Mar. 30, 2012 Potential Responsible Parties [Member] Subsequent Event [Member] Maximum [Member] Portland Harbor Superfund Site [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 40,855,000		$ 25,655,000	$ 15,200,000	$ 0	$ 1,000,000	$ 24,000,000
Liabilities Established (Released), Net	(300,000)		(300,000)	0
Payments and other	74,000		74,000	0
Ending balance	40,629,000		25,429,000	15,200,000	0	1,000,000	24,000,000
Short-Term	3,060,000	2,983,000	2,506,000	554,000
Long-Term	37,569,000	37,872,000	22,923,000	14,646,000
Number Of Potentially Responsible Parties Joining Allocation Process								80
Site Contingency Number of Years For Feasibility Study												10 years
Feasibiility Study Investigation Costs												100,000,000
Site Contingency Number of Remedial Alternatives									10
Site Contingency Least Costly Remediation Plan													170,000,000	250,000,000
Site Contingency Most Costly Remediation Plan													$ 1,080,000,000	$ 1,760,000,000
Site Contingency, Estimated Time Frame to Remediate										2 years	28 years
Annual production capacity (in tons)					950