Organization and Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	Effect of New Accounting Standards On March 31, 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The update is intended to simplify the current guidance for stock-based compensation for a range of issues including: the timing of income statement impact for tax benefits or deficiencies in excess of compensation cost, the classification of tax-related cash flows resulting from share based payments, the allowable threshold for tax withholding without resulting in liability award classification, and a policy election for estimating forfeiture rates or recognizing forfeitures as they occur. This guidance becomes effective at the beginning of our 2017 fiscal year, however as permitted, we plan to early adopt this guidance in the fourth quarter of 2016. The guidance requires a retrospective, modified-retrospective, or prospective transition method depending on the applicable section of the ASU. We estimate the effect of implementing this ASU on our Consolidated Balance Sheet would increase our deferred tax assets and retained earnings by approximately $5.1 million as of January 1, 2016, using the modified-retrospective transition method, for the cumulative-effect adjustment of excess tax benefits that were not previously recognized because the related tax deduction had not reduced current taxes payable. We have evaluated the aspects of this new guidance and, other than this one-time increase in deferred tax assets and retained earnings, the adoption of this ASU will not have a material impact on our accounting for share-based payments. On February 25, 2016, the FASB issued ASU 2016-02 - Leases (Topic 842), which supersedes the existing lease accounting guidance and establishes new criteria for recognizing lease assets and liabilities. The most significant impact of the update, to AAM, is that a lessee will be required to recognize a "right-of-use" asset and lease liability for operating lease agreements that were not previously included on the balance sheet under the existing lease guidance. A lessee will be permitted to make a policy election, excluding recognition of the right-of-use asset and associated liability for lease terms of 12 months or less. Expense recognition in the statement of income along with cash flow statement classification for both financing (capital) and operating leases under the new standard will not be significantly changed from existing lease guidance. Accounting for leases as a lessor under the new guidance remains also largely unchanged. This guidance becomes effective for AAM at the beginning of our 2019 fiscal year and requires transition under a modified retrospective method. We are currently assessing the impact that this standard will have on our condensed consolidated financial statements. On May 1, 2015, the FASB issued ASU 2015-07 - Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent), which changes the disclosure requirements for investments in certain entities that calculate net asset value (NAV) per share. Under current accounting standards entities are permitted to estimate the fair value of certain investments using the investment's NAV as a practical expedient. The current disclosure guidance also permits entities to disclose the investment at NAV in the fair value hierarchy table as either Level 2 or Level 3, based upon certain criteria. The measurement basis utilizing NAV is different than the measurement criteria of all other investments which utilize inputs to calculate fair value. Due to this inconsistency, the FASB issued this ASU which prohibits entities from categorizing investments measured at NAV within the fair value hierarchy. Other than the change in presentation, which requires retrospective application, the adoption of this new guidance will not have an impact on our condensed consolidated financial statements. AAM adopted this policy on January 1, 2016. In 2014, the FASB issued ASU 2014-09 - Revenue from Contracts with Customers (Topic 606), which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The guidance is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. On March 17, 2016, the FASB issued ASU 2016-08 - Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross Versus Net), to further clarify the new standard's guidance on identifying gross versus net reporting in the context of a contract. Based on the clarification, an entity should analyze the principal versus agent relationship for each specified good or service within a contract. On April 14, 2016, the FASB issued ASU 2016-10 - Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, which better articulates the principle for determining whether promised goods or services are separately identifiable in the context of the contract. The guidance also excludes from an entity's performance obligation analysis, the requirement to assess certain promised contract goods and services deemed immaterial in the context of the contract. On May 9, 2016, the FASB issued ASU 2016-12 - Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which addresses improvements to the guidance on collectibility, non-cash consideration, and completed contracts at transition. The update also provides a practical expedient for contract modifications at transition and a policy election related to the presentation of sales taxes and other similar taxes collected from customers. On August 12, 2015, the FASB issued ASU 2015-14 - Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, to formally defer the initial standard's effective date by one-year, making this guidance effective for AAM at the beginning of our 2018 fiscal year. We are currently assessing the impact that this standard will have on our condensed consolidated financial statements.
Authorized Share Repurchase Program [Policy Text Block]	Share Repurchase Program In the second quarter of 2016, AAM's Board of Directors authorized a share repurchase program of up to $100 million of AAM's common shares through December 31, 2018 as part of AAM's overall capital allocation strategy. The repurchase of shares may be made in the open market or in privately negotiated transactions and will be funded through available cash balances and cash flow from operations. The timing and amount of any share repurchases will be determined based on market and economic conditions, share price, alternative uses of capital and other factors. During the second quarter of 2016, we completed an initial share repurchase of 100,000 shares for $1.5 million under the authorized share repurchase program.

Effect of New Accounting Standards On March 31, 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The update is intended to simplify the current guidance for stock-based compensation for a range of issues including: the timing of income statement impact for tax benefits or deficiencies in excess of compensation cost, the classification of tax-related cash flows resulting from share based payments, the allowable threshold for tax withholding without resulting in liability award classification, and a policy election for estimating forfeiture rates or recognizing forfeitures as they occur. This guidance becomes effective at the beginning of our 2017 fiscal year, however as permitted, we plan to early adopt this guidance in the fourth quarter of 2016. The guidance requires a retrospective, modified-retrospective, or prospective transition method depending on the applicable section of the ASU. We estimate the effect of implementing this ASU on our Consolidated Balance Sheet would increase our deferred tax assets and retained earnings by approximately $5.1 million as of January 1, 2016, using the modified-retrospective transition method, for the cumulative-effect adjustment of excess tax benefits that were not previously recognized because the related tax deduction had not reduced current taxes payable. We have evaluated the aspects of this new guidance and, other than this one-time increase in deferred tax assets and retained earnings, the adoption of this ASU will not have a material impact on our accounting for share-based payments.

On February 25, 2016, the FASB issued ASU 2016-02 - Leases (Topic 842), which supersedes the existing lease accounting guidance and establishes new criteria for recognizing lease assets and liabilities. The most significant impact of the update, to AAM, is that a lessee will be required to recognize a "right-of-use" asset and lease liability for operating lease agreements that were not previously included on the balance sheet under the existing lease guidance. A lessee will be permitted to make a policy election, excluding recognition of the right-of-use asset and associated liability for lease terms of 12 months or less. Expense recognition in the statement of income along with cash flow statement classification for both financing (capital) and operating leases under the new standard will not be significantly changed from existing lease guidance. Accounting for leases as a lessor under the new guidance remains also largely unchanged. This guidance becomes effective for AAM at the beginning of our 2019 fiscal year and requires transition under a modified retrospective method. We are currently assessing the impact that this standard will have on our condensed consolidated financial statements.

On May 1, 2015, the FASB issued ASU 2015-07 - Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent), which changes the disclosure requirements for investments in certain entities that calculate net asset value (NAV) per share. Under current accounting standards entities are permitted to estimate the fair value of certain investments using the investment's NAV as a practical expedient. The current disclosure guidance also permits entities to disclose the investment at NAV in the fair value hierarchy table as either Level 2 or Level 3, based upon certain criteria. The measurement basis utilizing NAV is different than the measurement criteria of all other investments which utilize inputs to calculate fair value. Due to this inconsistency, the FASB issued this ASU which prohibits entities from categorizing investments measured at NAV within the fair value hierarchy. Other than the change in presentation, which requires retrospective application, the adoption of this new guidance will not have an impact on our condensed consolidated financial statements. AAM adopted this policy on January 1, 2016.

In 2014, the FASB issued ASU 2014-09 - Revenue from Contracts with Customers (Topic 606), which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The guidance is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. On March 17, 2016, the FASB issued ASU 2016-08 - Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross Versus Net), to further clarify the new standard's guidance on identifying gross versus net reporting in the context of a contract. Based on the clarification, an entity should analyze the principal versus agent relationship for each specified good or service within a contract. On April 14, 2016, the FASB issued ASU 2016-10 - Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, which better articulates the principle for determining whether promised goods or services are separately identifiable in the context of the contract. The guidance also excludes from an entity's performance obligation analysis, the requirement to assess certain promised contract goods and services deemed immaterial in the context of the contract. On May 9, 2016, the FASB issued ASU 2016-12 - Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which addresses improvements to the guidance on collectibility, non-cash consideration, and completed contracts at transition. The update also provides a practical expedient for contract modifications at transition and a policy election related to the presentation of sales taxes and other similar taxes collected from customers. On August 12, 2015, the FASB issued ASU 2015-14 - Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, to formally defer the initial standard's effective date by one-year, making this guidance effective for AAM at the beginning of our 2018 fiscal year. We are currently assessing the impact that this standard will have on our condensed consolidated financial statements.