Basis of Presentation	9 Months Ended
Sep. 30, 2014
Accounting Changes and Error Corrections [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation We prepared the accompanying unaudited consolidated financial statements in accordance with US Generally Accepted Accounting Principles ("GAAP") for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, our unaudited consolidated financial statements do not include all of the information and footnotes required for complete financial statements. We have included all of the normal recurring adjustments that we deemed necessary for a fair presentation. Operating results for the nine months ended September 30, 2014, are not necessarily indicative of the results we may achieve for the entire year ending December 31, 2014. In particular, ASC's fleet is inactive for a significant portion of the first quarter of each year due to winter conditions on the Great Lakes. In addition, asset remarketing income does not occur evenly throughout the year. For more information, refer to the consolidated financial statements and footnotes in our Annual Report on Form 10-K for the year ended December 31, 2013. Change in Accounting Estimate During the first quarter of 2014, we completed a review of the estimated useful lives used for our North American railcar fleet and determined that the economic service life of many of our railcars differed from the useful life currently used to calculate depreciation. As a result, effective January 1, 2014, we revised the estimated useful lives from a range of 30-38 years to a range of 27-42 years. In aggregate, the average depreciable life of the fleet increased approximately 2.2 years. The impacts of these implemented changes on depreciation expense for affected assets are a net decrease in depreciation expense of approximately $5.5 million and an increase in net income of $3.5 million, or $0.08 per diluted share in the third quarter of 2014; and a net decrease in depreciation expense of approximately $16.5 million and an increase in net income of $10.5 million, or $0.23 per diluted share in the first nine months of 2014. The full year impact for 2014 for affected assets is expected to be a decrease in depreciation expense of approximately $21.9 million and an increase in net income of $14.0 million, or approximately $0.30 per diluted share. New Accounting Pronouncements Discontinued Operations In April 2014, the Financial Accounting Standards Board ("FASB") issued amendments to authoritative guidance for reporting discontinued operations and disposals of components of an entity. The amendments require that disposals representing strategic shifts that have (or will have) a major effect on an entity’s operations or financial results should be reported in discontinued operations. The amendments also expand the disclosure requirements for both discontinued operations and significant dispositions that do not qualify as discontinued operations. The amendments are effective for us beginning in the first quarter of 2015, and early adoption is permitted for disposals that have not been previously reported. Adoption of the new guidance is not expected to impact the amount or timing of net income but may result in changes to the presentation and disclosures of our financial statements. Revenue from Contracts with Customers In May 2014, the FASB issued authoritative accounting guidance that supersedes most current revenue recognition guidance, including industry-specific guidance. The new guidance requires companies to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to be entitled to in exchange for those goods or services. The guidance is effective for us beginning in the first quarter of 2017, and early adoption is not permitted. We can adopt the new guidance using either the retrospective method or the cumulative effect transition method. We are still evaluating the effect that the new guidance will have on our consolidated financial statements and related disclosures, including which transition method we will use.
Change in Accounting Estimate, Description	Change in Accounting EstimateDuring the first quarter of 2014, we completed a review of the estimated useful lives used for our North American railcar fleet and determined that the economic service life of many of our railcars differed from the useful life currently used to calculate depreciation. As a result, effective January 1, 2014, we revised the estimated useful lives from a range of 30-38 years to a range of 27-42 years. In aggregate, the average depreciable life of the fleet increased approximately 2.2 years. The impacts of these implemented changes on depreciation expense for affected assets are a net decrease in depreciation expense of approximately $5.5 million and an increase in net income of $3.5 million, or $0.08 per diluted share in the third quarter of 2014; and a net decrease in depreciation expense of approximately $16.5 million and an increase in net income of $10.5 million, or $0.23 per diluted share in the first nine months of 2014. The full year impact for 2014 for affected assets is expected to be a decrease in depreciation expense of approximately $21.9 million and an increase in net income of $14.0 million, or approximately $0.30 per diluted share.

Basis of Presentation

We prepared the accompanying unaudited consolidated financial statements in accordance with US Generally Accepted Accounting Principles ("GAAP") for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, our unaudited consolidated financial statements do not include all of the information and footnotes required for complete financial statements. We have included all of the normal recurring adjustments that we deemed necessary for a fair presentation.

Operating results for the nine months ended September 30, 2014, are not necessarily indicative of the results we may achieve for the entire year ending December 31, 2014. In particular, ASC's fleet is inactive for a significant portion of the first quarter of each year due to winter conditions on the Great Lakes. In addition, asset remarketing income does not occur evenly throughout the year. For more information, refer to the consolidated financial statements and footnotes in our Annual Report on Form 10-K for the year ended December 31, 2013.

Change in Accounting Estimate

During the first quarter of 2014, we completed a review of the estimated useful lives used for our North American railcar fleet and determined that the economic service life of many of our railcars differed from the useful life currently used to calculate depreciation. As a result, effective January 1, 2014, we revised the estimated useful lives from a range of 30-38 years to a range of 27-42 years. In aggregate, the average depreciable life of the fleet increased approximately 2.2 years. The impacts of these implemented changes on depreciation expense for affected assets are a net decrease in depreciation expense of approximately $5.5 million and an increase in net income of $3.5 million, or $0.08 per diluted share in the third quarter of 2014; and a net decrease in depreciation expense of approximately $16.5 million and an increase in net income of $10.5 million, or $0.23 per diluted share in the first nine months of 2014. The full year impact for 2014 for affected assets is expected to be a decrease in depreciation expense of approximately $21.9 million and an increase in net income of $14.0 million, or approximately $0.30 per diluted share.

New Accounting Pronouncements

Discontinued Operations

In April 2014, the Financial Accounting Standards Board ("FASB") issued amendments to authoritative guidance for reporting discontinued operations and disposals of components of an entity. The amendments require that disposals representing strategic shifts that have (or will have) a major effect on an entity’s operations or financial results should be reported in discontinued operations. The amendments also expand the disclosure requirements for both discontinued operations and significant dispositions that do not qualify as discontinued operations.

The amendments are effective for us beginning in the first quarter of 2015, and early adoption is permitted for disposals that have not been previously reported. Adoption of the new guidance is not expected to impact the amount or timing of net income but may result in changes to the presentation and disclosures of our financial statements.

Revenue from Contracts with Customers

In May 2014, the FASB issued authoritative accounting guidance that supersedes most current revenue recognition guidance, including industry-specific guidance. The new guidance requires companies to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to be entitled to in exchange for those goods or services.

The guidance is effective for us beginning in the first quarter of 2017, and early adoption is not permitted. We can adopt the new guidance using either the retrospective method or the cumulative effect transition method. We are still evaluating the effect that the new guidance will have on our consolidated financial statements and related disclosures, including which transition method we will use.