Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The financial statements of Trinity Industries, Inc. and its consolidated subsidiaries (“Trinity”, “Company”, “we” or “our”) include the accounts of its wholly-owned subsidiaries and its partially-owned subsidiaries, TRIP Rail Holdings LLC ("TRIP Holdings") and RIV 2013 Rail Holdings LLC ("RIV 2013"), in which the Company has a controlling interest. All significant intercompany accounts and transactions have been eliminated. Stockholders' Equity On May 5, 2014, the Company's Board of Directors authorized a 2-for-1 stock split on its common shares. The stock split was issued in the form of a 100% stock dividend. The additional shares were distributed on June 19, 2014, to shareholders of record at the close of business on June 5, 2014. All share and per share information, including dividends, has been retroactively adjusted to reflect the 2-for-1 stock split, except for the statement of stockholders' equity which will reflect the stock split by reclassifying $78.0 million from "Capital in Excess of Par Value" to "Common Stock" representing the par value of the additional shares issued to effect the stock split. In March 2014, the Company’s Board of Directors authorized a new $250 million share repurchase program that expires on December 31, 2015 and replaced the Company's previously authorized $200 million share repurchase program. Under the new program, 747,246 shares were repurchased during the year ended December 31, 2014, at a cost of $31.5 million. During the year ended December 31, 2013, the Company repurchased 2,473,189 shares under the prior program at a cost of $108.2 million. Revenue Recognition Revenues for contracts providing for a large number of units and few deliveries are recorded as the individual units are produced, inspected, and accepted by the customer as the risk of loss passes to the customer upon delivery acceptance on these contracts. This occurs primarily in the Rail and Inland Barge Groups. Revenue from rentals and operating leases, including contracts which contain non-level fixed rental payments, is recognized monthly on a straight-line basis. Revenue is recognized from the sales of railcars from the lease fleet on a gross basis in leasing revenues and cost of revenues if the railcar has been owned for one year or less at the time of sale. Sales of railcars from the lease fleet that have been owned for more than one year are recognized as a net gain or loss from the disposal of a long-term asset. Fees for shipping and handling are recorded as revenue. For all other products, we recognize revenue when products are shipped or services are provided. Income Taxes The liability method is used to account for income taxes. Deferred income taxes represent the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Valuation allowances reduce deferred tax assets to an amount that will more likely than not be realized. The Company regularly evaluates the likelihood of realization of tax benefits derived from positions it has taken in various federal and state filings after consideration of all relevant facts, circumstances, and available information. For those tax positions that are deemed more likely than not to be sustained, the Company recognizes the benefit it believes is cumulatively greater than 50% likely to be realized. To the extent the Company were to prevail in matters for which accruals have been established or be required to pay amounts in excess of recorded reserves, the effective tax rate in a given financial statement period could be materially impacted. Financial Instruments The Company considers all highly liquid debt instruments to be either cash and cash equivalents if purchased with a maturity of three months or less, or short-term marketable securities if purchased with a maturity of more than three months and less than one year. The Company intends to hold its short-term marketable securities until they are redeemed at their maturity date and believes that under the "more likely than not" criteria, the Company will not be required to sell the securities before recovery of their amortized cost bases, which may be maturity. Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments including restricted cash, short-term marketable securities, and receivables. The Company places its cash investments and short-term marketable securities in bank deposits and investment grade, short-term debt instruments and limits the amount of credit exposure to any one commercial issuer. Concentrations of credit risk with respect to receivables are limited due to control procedures that monitor the credit worthiness of customers, the large number of customers in the Company's customer base, and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectibility of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. The carrying values of cash, short-term marketable securities, receivables and accounts payable are considered to be representative of their respective fair values. Inventories Inventories are valued at the lower of cost or market, with cost determined principally on the first in first out method. Market is replacement cost or net realizable value. Work in process and finished goods include material, labor, and overhead. Property, Plant, and Equipment Property, plant, and equipment are stated at cost and depreciated over their estimated useful lives using the straight-line method. The estimated useful lives are: buildings and improvements - 3 to 30 years; leasehold improvements - the lesser of the term of the lease or 7 years; machinery and equipment - 2 to 10 years; information systems hardware and software - 2 to 5 years; and railcars in our lease fleet - generally 35 years. The costs of ordinary maintenance and repair are charged to operating costs while renewals and major replacements are capitalized. Long-lived Assets The Company periodically evaluates the carrying value of long-lived assets to be held and used for potential impairment. The carrying value of long-lived assets to be held and used is considered impaired only when their carrying value is not recoverable through undiscounted future cash flows and the fair value of the assets is less than their carrying value. Fair value is determined primarily using the anticipated cash flows discounted at a rate commensurate with the risks involved or market quotes as available. Impairment losses on long-lived assets held for sale are determined in a similar manner, except that fair values are reduced by the estimated cost to dispose of the assets. Impairment losses were not material for the years ended December 31, 2014, 2013, and 2012. Goodwill and Intangible Assets Goodwill is required to be tested for impairment annually, or on an interim basis whenever events or circumstances change, indicating that the carrying amount of the goodwill might be impaired. The goodwill impairment test is a two-step process with step one requiring the comparison of the reporting unit's estimated fair value with the carrying amount of its net assets. If necessary, step two of the impairment test determines the amount of goodwill impairment to be recorded when the reporting unit's recorded net assets exceed its fair value. Impairment is assessed at the “reporting unit” level by applying a fair value-based test for each unit with recorded goodwill. The estimates and judgments that most significantly affect the fair value calculations are assumptions, consisting of level three inputs, related to revenue and operating profit growth, discount rates and exit multiples. During the three months ended December 31, 2014, the Company considered certain state actions with regard to its highway products litigation as an indicator of possible goodwill impairment. See Note 18 Commitments and Contingencies for a fuller explanation of this matter. As of December 31, 2014 and 2013, the Company's annual impairment test of goodwill was completed at the reporting unit level and no impairment charges were determined to be necessary. Intangible assets with defined useful lives, which as of December 31, 2014 had net book values of $58.8 million, are amortized over their estimated useful lives, and were also evaluated for potential impairment as of December 31, 2014. Restricted Cash Restricted cash consists of cash and cash equivalents that are held either as collateral for the Company's non-recourse debt and lease obligations or security for the performance of certain product sales agreements and as such are restricted in use. Insurance The Company is effectively self-insured for workers' compensation claims. A third party administrator is used to process claims. We accrue our workers' compensation liability based upon independent actuarial studies. Warranties Depending on the product, the Company provides warranties against materials and manufacturing defects generally ranging from one to five years. The warranty costs are estimated using a two-step approach. First, an engineering estimate is made for the cost of all claims that have been asserted by customers. Second, based on historical claims experience, a cost is accrued for all products still within a warranty period for which no claims have been filed. The Company provides for the estimated cost of product warranties at the time revenue is recognized related to products covered by warranties, and assesses the adequacy of the resulting reserves on a quarterly basis. Foreign Currency Translation Operations outside the United States prepare financial statements in currencies other than the United States dollar. The income statement amounts are translated at average exchange rates for the year, while the assets and liabilities are translated at year-end exchange rates. Translation adjustments are accumulated as a separate component of stockholders' equity and other comprehensive income. The functional currency of our Mexico operations is considered to be the United States dollar. The functional currency of our Canadian operations is considered to be the Canadian dollar. Other Comprehensive Income (Loss) Other comprehensive net income (loss) consists of foreign currency translation adjustments, the effective unrealized gains and losses on the Company's derivative financial instruments, and the net actuarial gains and losses of the Company's defined benefit plans, the sum of which, along with net income (loss), constitutes comprehensive net income (loss). See Note 15 Accumulated Other Comprehensive Loss (“AOCL”). All components are shown net of tax. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-09, "Revenue from Contracts with Customers," ("ASU 2014-09") providing common revenue recognition guidance for U.S. GAAP. Under ASU 2014-09, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. It also requires additional detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. ASU 2014-09 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2016. Early application is not permitted. We are currently evaluating the impact this standard will have on our consolidated financial statements. Management's Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Reclassifications Certain prior year balances have been reclassified in the consolidated financial statements to conform to the 2014 presentation.

Summary of Significant Accounting Policies

Principles of Consolidation

The financial statements of Trinity Industries, Inc. and its consolidated subsidiaries (“Trinity”, “Company”, “we” or “our”) include the accounts of its wholly-owned subsidiaries and its partially-owned subsidiaries, TRIP Rail Holdings LLC ("TRIP Holdings") and RIV 2013 Rail Holdings LLC ("RIV 2013"), in which the Company has a controlling interest. All significant intercompany accounts and transactions have been eliminated.

Stockholders' Equity

On May 5, 2014, the Company's Board of Directors authorized a 2-for-1 stock split on its common shares. The stock split was issued in the form of a 100% stock dividend. The additional shares were distributed on June 19, 2014, to shareholders of record at the close of business on June 5, 2014. All share and per share information, including dividends, has been retroactively adjusted to reflect the 2-for-1 stock split, except for the statement of stockholders' equity which will reflect the stock split by reclassifying $78.0 million from "Capital in Excess of Par Value" to "Common Stock" representing the par value of the additional shares issued to effect the stock split.

In March 2014, the Company’s Board of Directors authorized a new $250 million share repurchase program that expires on December 31, 2015 and replaced the Company's previously authorized $200 million share repurchase program. Under the new program, 747,246 shares were repurchased during the year ended December 31, 2014, at a cost of $31.5 million. During the year ended December 31, 2013, the Company repurchased 2,473,189 shares under the prior program at a cost of $108.2 million.

Revenue Recognition

Revenues for contracts providing for a large number of units and few deliveries are recorded as the individual units are produced, inspected, and accepted by the customer as the risk of loss passes to the customer upon delivery acceptance on these contracts. This occurs primarily in the Rail and Inland Barge Groups. Revenue from rentals and operating leases, including contracts which contain non-level fixed rental payments, is recognized monthly on a straight-line basis. Revenue is recognized from the sales of railcars from the lease fleet on a gross basis in leasing revenues and cost of revenues if the railcar has been owned for one year or less at the time of sale. Sales of railcars from the lease fleet that have been owned for more than one year are recognized as a net gain or loss from the disposal of a long-term asset. Fees for shipping and handling are recorded as revenue. For all other products, we recognize revenue when products are shipped or services are provided.

Income Taxes

The liability method is used to account for income taxes. Deferred income taxes represent the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Valuation allowances reduce deferred tax assets to an amount that will more likely than not be realized.

The Company regularly evaluates the likelihood of realization of tax benefits derived from positions it has taken in various federal and state filings after consideration of all relevant facts, circumstances, and available information. For those tax positions that are deemed more likely than not to be sustained, the Company recognizes the benefit it believes is cumulatively greater than 50% likely to be realized. To the extent the Company were to prevail in matters for which accruals have been established or be required to pay amounts in excess of recorded reserves, the effective tax rate in a given financial statement period could be materially impacted.

Financial Instruments

The Company considers all highly liquid debt instruments to be either cash and cash equivalents if purchased with a maturity of three months or less, or short-term marketable securities if purchased with a maturity of more than three months and less than one year. The Company intends to hold its short-term marketable securities until they are redeemed at their maturity date and believes that under the "more likely than not" criteria, the Company will not be required to sell the securities before recovery of their amortized cost bases, which may be maturity.

Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments including restricted cash, short-term marketable securities, and receivables. The Company places its cash investments and short-term marketable securities in bank deposits and investment grade, short-term debt instruments and limits the amount of credit exposure to any one commercial issuer. Concentrations of credit risk with respect to receivables are limited due to control procedures that monitor the credit worthiness of customers, the large number of customers in the Company's customer base, and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectibility of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. The carrying values of cash, short-term marketable securities, receivables and accounts payable are considered to be representative of their respective fair values.

Inventories

Inventories are valued at the lower of cost or market, with cost determined principally on the first in first out method. Market is replacement cost or net realizable value. Work in process and finished goods include material, labor, and overhead.

Property, Plant, and Equipment

Property, plant, and equipment are stated at cost and depreciated over their estimated useful lives using the straight-line method. The estimated useful lives are: buildings and improvements - 3 to 30 years; leasehold improvements - the lesser of the term of the lease or 7 years; machinery and equipment - 2 to 10 years; information systems hardware and software - 2 to 5 years; and railcars in our lease fleet - generally 35 years. The costs of ordinary maintenance and repair are charged to operating costs while renewals and major replacements are capitalized.

Long-lived Assets

The Company periodically evaluates the carrying value of long-lived assets to be held and used for potential impairment. The carrying value of long-lived assets to be held and used is considered impaired only when their carrying value is not recoverable through undiscounted future cash flows and the fair value of the assets is less than their carrying value. Fair value is determined primarily using the anticipated cash flows discounted at a rate commensurate with the risks involved or market quotes as available. Impairment losses on long-lived assets held for sale are determined in a similar manner, except that fair values are reduced by the estimated cost to dispose of the assets. Impairment losses were not material for the years ended December 31, 2014, 2013, and 2012.

Goodwill and Intangible Assets

Goodwill is required to be tested for impairment annually, or on an interim basis whenever events or circumstances change, indicating that the carrying amount of the goodwill might be impaired. The goodwill impairment test is a two-step process with step one requiring the comparison of the reporting unit's estimated fair value with the carrying amount of its net assets. If necessary, step two of the impairment test determines the amount of goodwill impairment to be recorded when the reporting unit's recorded net assets exceed its fair value. Impairment is assessed at the “reporting unit” level by applying a fair value-based test for each unit with recorded goodwill. The estimates and judgments that most significantly affect the fair value calculations are assumptions, consisting of level three inputs, related to revenue and operating profit growth, discount rates and exit multiples. During the three months ended December 31, 2014, the Company considered certain state actions with regard to its highway products litigation as an indicator of possible goodwill impairment. See Note 18 Commitments and Contingencies for a fuller explanation of this matter. As of December 31, 2014 and 2013, the Company's annual impairment test of goodwill was completed at the reporting unit level and no impairment charges were determined to be necessary.

Intangible assets with defined useful lives, which as of December 31, 2014 had net book values of $58.8 million, are amortized over their estimated useful lives, and were also evaluated for potential impairment as of December 31, 2014.

Restricted Cash

Restricted cash consists of cash and cash equivalents that are held either as collateral for the Company's non-recourse debt and lease obligations or security for the performance of certain product sales agreements and as such are restricted in use.

Insurance

The Company is effectively self-insured for workers' compensation claims. A third party administrator is used to process claims. We accrue our workers' compensation liability based upon independent actuarial studies.

Warranties

Depending on the product, the Company provides warranties against materials and manufacturing defects generally ranging from one to five years. The warranty costs are estimated using a two-step approach. First, an engineering estimate is made for the cost of all claims that have been asserted by customers. Second, based on historical claims experience, a cost is accrued for all products still within a warranty period for which no claims have been filed. The Company provides for the estimated cost of product warranties at the time revenue is recognized related to products covered by warranties, and assesses the adequacy of the resulting reserves on a quarterly basis.

Foreign Currency Translation

Operations outside the United States prepare financial statements in currencies other than the United States dollar. The income statement amounts are translated at average exchange rates for the year, while the assets and liabilities are translated at year-end exchange rates. Translation adjustments are accumulated as a separate component of stockholders' equity and other comprehensive income. The functional currency of our Mexico operations is considered to be the United States dollar. The functional currency of our Canadian operations is considered to be the Canadian dollar.

Other Comprehensive Income (Loss)

Other comprehensive net income (loss) consists of foreign currency translation adjustments, the effective unrealized gains and losses on the Company's derivative financial instruments, and the net actuarial gains and losses of the Company's defined benefit plans, the sum of which, along with net income (loss), constitutes comprehensive net income (loss). See Note 15 Accumulated Other Comprehensive Loss (“AOCL”). All components are shown net of tax.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-09, "Revenue from Contracts with Customers," ("ASU 2014-09") providing common revenue recognition guidance for U.S. GAAP. Under ASU 2014-09, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects what it expects in exchange for the goods or services. It also requires additional detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. ASU 2014-09 will become effective for public companies during interim and annual reporting periods beginning after December 15, 2016. Early application is not permitted. We are currently evaluating the impact this standard will have on our consolidated financial statements.

Management's Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Reclassifications

Certain prior year balances have been reclassified in the consolidated financial statements to conform to the 2014 presentation.