Commitments and Contingencies (Details) T in Thousands			1 Months Ended				9 Months Ended
	Jan. 30, 2017 party	Mar. 30, 2012 USD ($) remediation_alternative	Jan. 31, 2017 USD ($)	Jun. 30, 2016 USD ($) alternatives remediation_alternative	Nov. 30, 2015 USD ($)	Aug. 31, 2015 USD ($) alternatives	May 31, 2017 USD ($) potentially_responsible_party T	Sep. 30, 2016 commentors	Aug. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Parties Liable in Litigation | party	30
Litigation Liability							$ 48,187,000		$ 46,350,000
Auto and Metals Recycling
Loss Contingencies [Line Items]
Litigation Liability							48,067,000		46,122,000
Steel Manufacturing Business
Loss Contingencies [Line Items]
Litigation Liability							$ 0		0
Permitted Annual production capacity | T							950
Permit Expiration Date							Feb. 01, 2018
Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Number Of Potentially Responsible Parties | potentially_responsible_party							100
Litigation Liability							$ 1,000,000
Number of comments submitted | commentors								5,300
Other Auto and Metals Recycling Sites
Loss Contingencies [Line Items]
Litigation Liability							$ 47,000,000		$ 45,000,000
Lower Willamette Group | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Period Of Feasibility Study		10 years
Feasibility Study, Investigation Costs		$ 100,000,000
Site Contingency, Number of Remedial Alternatives | remediation_alternative		10
Lower Willamette Group | Minimum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan		$ 170,000,000
Site Contingency, Most Costly Remediation Plan		$ 1,080,000,000
Site Contingency, Estimated Time Frame to Remediate		2 years
Lower Willamette Group | Maximum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan		$ 250,000,000
Site Contingency, Most Costly Remediation Plan		$ 1,760,000,000
Site Contingency, Estimated Time Frame to Remediate		28 years
EPA Region 10 | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Number of Remedial Alternatives | alternatives				8
Alternative Implementation Period on Regulatory Actions				7 years
Estimated Cost on Alternative Regulatory Action Plan				$ 746,000,000	$ 1,400,000,000
Number of Possible Disposal Alternatives for Site Contingency Remedial Alternatives | remediation_alternative				2
Site Contingency, Number of Remedial Alternatives Scenarios | remediation_alternative				13
EPA Region 10 | Minimum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan				$ 316,000,000
Site Contingency, Most Costly Remediation Plan				$ 1,210,000,000
Site Contingency, Estimated Time Frame to Remediate				4 years
EPA Region 10 | Maximum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan				$ 677,000,000
Site Contingency, Most Costly Remediation Plan				$ 2,670,000,000
Site Contingency, Estimated Time Frame to Remediate				19 years
Potential Responsible Parties | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Number of Remedial Alternatives | alternatives						5
Site Contingency, Estimated Time Frame to Remediate			13 years
Estimated Cost of Selected Remedy			$ 1,700,000,000
Estimated Cost of Selected Remedy, Discount			$ 1,050,000,000
Estimated Cost of Selected Remedy, Discount Rate			7.00%
Potential Responsible Parties | Minimum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan						$ 550,000,000
Site Contingency, Most Costly Remediation Plan						$ 1,710,000,000
Site Contingency, Estimated Time Frame to Remediate						4 years
Estimated Cost of Selected Remedy, Range			30.00%
Potential Responsible Parties | Maximum | Portland Harbor Superfund Site
Loss Contingencies [Line Items]
Site Contingency, Least Costly Remediation Plan						$ 1,190,000,000
Site Contingency, Most Costly Remediation Plan						$ 3,670,000,000
Site Contingency, Estimated Time Frame to Remediate						18 years
Estimated Cost of Selected Remedy, Range			50.00%