Commitments and Contingencies	3 Months Ended
Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments. We have a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness and letters of credit (see Note 3 and Note 8). Environmental Contingencies. We are subject to a number of environmental laws and regulations, to potential fines or penalties assessed for alleged breaches of such laws and regulations and to potential claims based upon such laws and regulations. We are also subject to legacy environmental contingencies related to activities that occurred at operating facilities within Fabricated Products prior to July 6, 2006 while such operating facilities were being operated by a predecessor, which represent the majority of our environmental accruals. The status of these environmental contingencies are discussed below. We have established procedures for regularly evaluating environmental loss contingencies. Our environmental accruals represent our undiscounted estimate of costs reasonably expected to be incurred based on presently enacted laws and regulations, existing requirements, currently available facts, existing technology and our assessment of the likely remediation actions to be taken. In 2012, we submitted a final feasibility study to the Washington State Department of Ecology ("Washington State Ecology") that included recommendations for remediation alternatives primarily to address the historical use of oils containing polychlorinated biphenyls ("PCBs") at our Spokane, Washington ("Trentwood") facility. We also signed an amended work order in 2012 with Washington State Ecology allowing certain remediation activities to begin, including the initiation of a treatability study in regards to proposed PCB remediation methods. We began implementation of certain approved sections of the work plan in 2013 and throughout 2014, completing a number of these sections in 2014 and receiving approval from Washington State Ecology on completed sections. In cooperation with Washington State Ecology, in 2015 we constructed a pilot test facility to determine the treatability and evaluate the feasibility of removing PCBs from ground water under the Trentwood facility. We initiated and began operating the treatment test facility in the first half of 2016. As the success of the new methodology cannot be reasonably determined at this time, it is possible we may need to make upward adjustments to our related accruals as facts and cost estimates regarding the groundwater treatment method and the operation of the treatment facility become available. During 2013, at the request of the Ohio Environmental Protection Agency ("OEPA"), we initiated an investigational study of the Newark, Ohio ("Newark") facility related to historical on-site waste disposal. Since 2014, we completed a number of preliminary steps in the preparation of completing the final risk assessment and feasibility study, both of which are subject to review and approval by the OEPA. As work continues and progresses to a final risk assessment and feasibility study, we will establish and update estimates for probable and estimable remediation, if any. The actual and final cost for remediation will not be fully determinable until a final feasibility study is submitted and accepted by the OEPA and work plans are prepared, which is expected to occur in the next 12 to 15 months. At March 31, 2017, our environmental accrual of $17.1 million represented our estimate of the incremental remediation cost based on: (i) proposed alternatives in the final feasibility study related to the Trentwood facility; (ii) currently available facts with respect to our Newark facility; and (iii) facts related to certain other locations owned or formerly owned by us. In accordance with approved and proposed remediation action plans, we expect that the implementation and ongoing monitoring could occur over a period of 30 or more years. As additional facts are developed, feasibility studies are completed, draft remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed, and/or other factors change, there may be revisions to management's estimates and actual costs may exceed the current environmental accruals. We believe at this time that it is reasonably possible that undiscounted costs associated with these environmental matters may exceed current accruals by amounts that could be, in the aggregate, up to an estimated $12.3 million over the remediation period. It is reasonably possible that our recorded estimate will change in the next 12 months. Other Contingencies. We are party to various lawsuits, claims, investigations and administrative proceedings that arise in connection with past and current operations. We evaluate such matters on a case-by-case basis and our policy is to vigorously contest any such claims we believe are without merit. We accrue for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, we review and adjust these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, we believe that we have sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on our consolidated financial position, operating results or liquidity.

Commitments and Contingencies

Commitments. We have a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness and letters of credit (see Note 3 and Note 8).

Environmental Contingencies. We are subject to a number of environmental laws and regulations, to potential fines or penalties assessed for alleged breaches of such laws and regulations and to potential claims based upon such laws and regulations. We are also subject to legacy environmental contingencies related to activities that occurred at operating facilities within Fabricated Products prior to July 6, 2006 while such operating facilities were being operated by a predecessor, which represent the majority of our environmental accruals. The status of these environmental contingencies are discussed below. We have established procedures for regularly evaluating environmental loss contingencies. Our environmental accruals represent our undiscounted estimate of costs reasonably expected to be incurred based on presently enacted laws and regulations, existing requirements, currently available facts, existing technology and our assessment of the likely remediation actions to be taken.

In 2012, we submitted a final feasibility study to the Washington State Department of Ecology ("Washington State Ecology") that included recommendations for remediation alternatives primarily to address the historical use of oils containing polychlorinated biphenyls ("PCBs") at our Spokane, Washington ("Trentwood") facility. We also signed an amended work order in 2012 with Washington State Ecology allowing certain remediation activities to begin, including the initiation of a treatability study in regards to proposed PCB remediation methods. We began implementation of certain approved sections of the work plan in 2013 and throughout 2014, completing a number of these sections in 2014 and receiving approval from Washington State Ecology on completed sections. In cooperation with Washington State Ecology, in 2015 we constructed a pilot test facility to determine the treatability and evaluate the feasibility of removing PCBs from ground water under the Trentwood facility. We initiated and began operating the treatment test facility in the first half of 2016. As the success of the new methodology cannot be reasonably determined at this time, it is possible we may need to make upward adjustments to our related accruals as facts and cost estimates regarding the groundwater treatment method and the operation of the treatment facility become available.

During 2013, at the request of the Ohio Environmental Protection Agency ("OEPA"), we initiated an investigational study of the Newark, Ohio ("Newark") facility related to historical on-site waste disposal. Since 2014, we completed a number of preliminary steps in the preparation of completing the final risk assessment and feasibility study, both of which are subject to review and approval by the OEPA. As work continues and progresses to a final risk assessment and feasibility study, we will establish and update estimates for probable and estimable remediation, if any. The actual and final cost for remediation will not be fully determinable until a final feasibility study is submitted and accepted by the OEPA and work plans are prepared, which is expected to occur in the next 12 to 15 months.

At March 31, 2017, our environmental accrual of $17.1 million represented our estimate of the incremental remediation cost based on: (i) proposed alternatives in the final feasibility study related to the Trentwood facility; (ii) currently available facts with respect to our Newark facility; and (iii) facts related to certain other locations owned or formerly owned by us. In accordance with approved and proposed remediation action plans, we expect that the implementation and ongoing monitoring could occur over a period of 30 or more years.

As additional facts are developed, feasibility studies are completed, draft remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed, and/or other factors change, there may be revisions to management's estimates and actual costs may exceed the current environmental accruals. We believe at this time that it is reasonably possible that undiscounted costs associated with these environmental matters may exceed current accruals by amounts that could be, in the aggregate, up to an estimated $12.3 million over the remediation period. It is reasonably possible that our recorded estimate will change in the next 12 months.

Other Contingencies. We are party to various lawsuits, claims, investigations and administrative proceedings that arise in connection with past and current operations. We evaluate such matters on a case-by-case basis and our policy is to vigorously contest any such claims we believe are without merit. We accrue for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, we review and adjust these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, we believe that we have sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on our consolidated financial position, operating results or liquidity.