SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Consolidation	The consolidated financial statements reflect the accounts of the Company and its wholly-owned and majority-owned subsidiaries. All significant intercompany profits, transactions and balances have been eliminated in consolidation.
Reclassifications	Certain prior period amounts have been reclassified to conform to the current year presentation.
Use of Estimates	The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that directly affect the amounts reported in its consolidated financial statements and accompanying notes. Actual results could differ from these estimates.
Cash and Cash Equivalents	Cash and cash equivalents include all highly liquid investments with a maturity of three months or less at the time of purchase.
Accounts Receivable	Accounts receivable are shown net of allowance for doubtful accounts and primarily include trade receivables. The Company records and maintains a provision for doubtful accounts for customers based upon a variety of factors including the Company’s historical collection experience, the length of time the account has been outstanding and the financial condition of the customer. If the circumstances related to specific customers were to change, the Company’s estimates with respect to the collectability of the related accounts could be further adjusted. The Company’s policy is to write-off receivables when they are determined to be uncollectible. Provisions to the allowance for doubtful accounts are charged to Selling and General and Administrative Expenses in the Consolidated Statements of Operations.
Inventories	Inventories are stated at the lower of cost, determined on either the first-in, first-out or average cost method, or net realizable value. The cost of manufactured inventory includes raw material, labor and overhead.
Prepaid Expenses and Other	Chassis converter pool agreements represent chassis transferred to the Company on a restricted basis by the manufacturer, who retains the sole authority to authorize commencement of work on the chassis and to make certain other decisions with respect to the chassis including the terms and pricing of sales to the manufacturer’s dealers. Assets held for sale are related to the Company’s locations which are being actively marketed for sale. Insurance premiums and maintenance agreements are charged to expense over the contractual life, which is generally one year or less. Other prepaid items consist primarily of costs in excess of billings on contracts for which the Company recognizes revenue on an over time basis and investments held by the Company’s captive insurance subsidiary.
Property, Plant and Equipment	Property, plant and equipment are recorded at cost, net of accumulated depreciation. Maintenance and repairs are charged to expense as incurred, while expenditures that extend the useful life of an asset are capitalized. Depreciation is recorded using the straight-line method over the estimated useful lives of the depreciable assets. The estimated useful lives are up to 33 years for buildings and building improvements and range from three to ten years for machinery and equipment.
Goodwill	Goodwill represents the excess purchase price over fair value of the net assets acquired. The Company reviews goodwill for impairment, at the reporting unit level, annually on October 1 and whenever events or changes in circumstances indicate its carrying value may not be recoverable. In accordance with ASC 350, Intangibles – Goodwill and Other, goodwill is reviewed for impairment utilizing either a qualitative assessment or a quantitative process. The Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. An entity has an unconditional option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test, which is the option the Company has historically chosen. For reporting units in which the Company performs the quantitative analysis, the Company compares the carrying value, including goodwill, of each reporting unit with its estimated fair value. If the fair value of the reporting unit exceeds its carrying value, the goodwill is not considered impaired. If the carrying value is greater than the fair value, the difference is recognized as an impairment loss charged to the reporting unit. After an impairment loss is recognized, the adjusted carrying amount of goodwill shall be its new accounting basis.
Long-Lived Assets	Long-lived assets, consisting primarily of intangible assets and property, plant and equipment, are reviewed for impairment whenever facts and circumstances indicate that the carrying amount may not be recoverable. Specifically, this process involves comparing an asset’s carrying value to the estimated undiscounted future cash flows the asset is expected to generate over its remaining life. If this process were to result in the conclusion that the carrying value of a long-lived asset would not be recoverable, a write-down of the asset to fair value would be recorded through a charge to operations. Fair value is determined based upon discounted cash flows or appraisals as appropriate.
Other Assets	The Company capitalizes the cost of computer software developed or obtained for internal use. Capitalized software is amortized using the straight-line method over three to seven years.
Warranties	The Company offers a limited warranty for its products with a coverage period that ranges between one and five years, except that the coverage period for DuraPlate^® trailer panels is ten years. The Company passes through component manufacturers’ warranties to our customers. The Company’s policy is to accrue the estimated cost of warranty coverage at the time of the sale.
Self Insured Liabilities	The Company is self-insured up to specified limits for medical and workers’ compensation coverage. The self-insurance reserves have been recorded to reflect the undiscounted estimated liabilities, including claims incurred but not reported, as well as catastrophic claims as appropriate.
Income Taxes	The Company determines its provision or benefit for income taxes under the asset and liability method. The asset and liability method measures the expected tax impact at current enacted rates of future taxable income or deductions resulting from differences in the tax and financial reporting basis of assets and liabilities reflected in the Consolidated Balance Sheets. Future tax benefits of tax losses and credit carryforwards are recognized as deferred tax assets. Deferred tax assets are reduced by a valuation allowance to the extent management determines that it is more-likely-than-not the Company would not realize the value of these assets. The Company accounts for income tax contingencies by prescribing a “more-likely-than-not” recognition threshold that a tax position is required to meet before being recognized in the financial statements.
Used Trailer Trade Commitments	The Company may accept trade-in of used trailers when a customer enters into a contract to purchase a new trailer. However, in the contracts for the sale of the new trailers, there is no commitment to repurchase that trailer or a similar trailer in the future. The Company acquired used trailers on trade of $3.2 million, $9.5 million, and $4.6 million in 2018, 2017, and 2016, respectively. As of December 31, 2018, the Company had no outstanding trade commitments and $3.2 million as of December 31, 2017, which also represented the estimated net realizable value of the underlying used trailer. On occasion, the amount of the trade allowance provided for in the used trailer commitments, or cost, may exceed the net realizable value of the underlying used trailer. In these instances, the Company’s policy is to recognize the loss related to these commitments at the time the new trailer revenue is recognized. Net realizable value of used trailers is measured considering market sales data for comparable types of trailers.
Concentration of Credit Risk	Financial instruments that potentially subject us to significant concentrations of credit risk consist principally of cash, cash equivalents and customer receivables. We place our cash and cash equivalents with high quality financial institutions. Generally, we do not require collateral or other security to support customer receivables.
Research and Development	Research and development expenses are charged to Cost of Sales and General and Administrative Expenses in the Consolidated Statements of Operations as incurred and were $8.8 million, $3.9 million and $6.4 million in 2018, 2017 and 2016, respectively.
New Accounting Pronouncements	In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This update requires lessees to recognize, on the balance sheet, assets and liabilities for the rights and obligations created by leases of greater than twelve months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. We have identified our existing lease contracts and have entered data within the contracts needed for the calculation of the right of use assets and lease liabilities into software to build our repository of lease contracts and to assist us with the accounting entries. This guidance is effective for the Company as of January 1, 2019. The FASB has issued further ASUs related to the standard providing an optional transition method allowing entities to not recast comparative periods. The Company intends to use the optional transition method and, as such, recognize the effects of applying the new standard as a cumulative-effect adjustment to retained earnings as of January 1, 2019. The Company plans to elect the practical expedients upon transition that will retain the lease classification and initial direct costs for any leases that exist prior to adoption of the standard. Wabash will not reassess whether any contracts entered into prior to adoption are leases. On adoption, we currently expect to record right of use assets and lease liabilities in the range of $9.2 million to $10.2 million, based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash, which requires entities to show the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one item on the balance sheet, a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet is required. This guidance was adopted by the Company on January 1, 2018 and was applied retrospectively. In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment (“ASU 2017-4”). ASU 2017-4 eliminates Step 2 of the current goodwill impairment test, which requires a hypothetical purchase price allocation to measure goodwill impairment. A goodwill impairment loss will instead be measured at the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the recorded amount of goodwill. The new standard is effective for annual and interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. Early adoption is permitted for annual or interim goodwill impairment testing performed after January 1, 2017. The Company early adopted ASU 2017-04 in the third quarter of 2018. The company recognized a $4.9 million goodwill impairment charge during the three months ended September 30, 2018 (refer to Note 6 for more information). In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities (“ASU 2017-12”). ASU 2017-12 eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The new standard is effective for fiscal years beginning after December 15, 2018. Early adoption is permitted in any fiscal year or interim period before the effective date. The Company early adopted ASU 2017-12 in the fourth quarter of 2018.
Revenue from Contract with Customer	The Company recognizes revenue from the sale of its products when obligations under the terms of a contract with our customers are satisfied; this occurs with the transfer of control of our products and replacement parts or throughout the completion of service work. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring promised goods or services to a customer and excludes all taxes collected from the customer. Shipping and handling fees are included in Net Sales and the associated costs included in Cost of Sales in the Consolidated Statements of Operations. For shipping and handling costs that take place after the transfer of control, the Company is applying the practical expedient and treating it as a fulfillment cost. Incidental items that are immaterial in the context of the contract are recognized as expense. For performance obligations satisfied over time, which include certain equipment-related sales within our Diversified Products reportable segment that have no alternative use and contain an enforceable right to payment, as well as service work whereby the customer simultaneously receives and consumes the benefits provided, the Company recognizes revenue on the basis of the Company’s efforts or inputs to the satisfaction of these performance obligations, measured by actual total cost incurred to the total estimated costs for each project. Total revenue recognized over time was not material to the consolidated financial statements for all periods presented. The Company has identified three separate and distinct performance obligations: 1) the sale of a trailer or equipment, 2) the sale of replacement parts, and 3) service work. For trailer, truck body, equipment, and replacement part sales, control is transferred and revenue is recognized from the sale upon shipment to or pick up by the customer in accordance with the contract terms. The Company does not have any material extended payment terms as payment is received shortly after the point of sale. Accounts receivable are recorded when the right to consideration becomes unconditional. The Company does have customers who pay for the product prior to the transfer of control which is recorded as customer deposits in Other Accrued Liabilities as shown in Note 9. Customer deposits are recognized as revenue when the Company performs its obligations under the contract and transfers control of the product.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2018

The consolidated financial statements reflect the accounts of the Company and its wholly-owned and majority-owned subsidiaries. All significant intercompany profits, transactions and balances have been eliminated in consolidation.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current year presentation.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that directly affect the amounts reported in its consolidated financial statements and accompanying notes. Actual results could differ from these estimates.

Cash and Cash Equivalents

Cash and cash equivalents include all highly liquid investments with a maturity of three months or less at the time of purchase.

Accounts Receivable

Accounts receivable are shown net of allowance for doubtful accounts and primarily include trade receivables. The Company records and maintains a provision for doubtful accounts for customers based upon a variety of factors including the Company’s historical collection experience, the length of time the account has been outstanding and the financial condition of the customer. If the circumstances related to specific customers were to change, the Company’s estimates with respect to the collectability of the related accounts could be further adjusted. The Company’s policy is to write-off receivables when they are determined to be uncollectible. Provisions to the allowance for doubtful accounts are charged to Selling and General and Administrative Expenses in the Consolidated Statements of Operations.

Inventories

Inventories are stated at the lower of cost, determined on either the first-in, first-out or average cost method, or net realizable value. The cost of manufactured inventory includes raw material, labor and overhead.

Prepaid Expenses and Other

Chassis converter pool agreements represent chassis transferred to the Company on a restricted basis by the manufacturer, who retains the sole authority to authorize commencement of work on the chassis and to make certain other decisions with respect to the chassis including the terms and pricing of sales to the manufacturer’s dealers. Assets held for sale are related to the Company’s locations which are being actively marketed for sale. Insurance premiums and maintenance agreements are charged to expense over the contractual life, which is generally one year or less. Other prepaid items consist primarily of costs in excess of billings on contracts for which the Company recognizes revenue on an over time basis and investments held by the Company’s captive insurance subsidiary.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost, net of accumulated depreciation. Maintenance and repairs are charged to expense as incurred, while expenditures that extend the useful life of an asset are capitalized. Depreciation is recorded using the straight-line method over the estimated useful lives of the depreciable assets. The estimated useful lives are up to 33 years for buildings and building improvements and range from three to ten years for machinery and equipment.

Goodwill

Goodwill represents the excess purchase price over fair value of the net assets acquired. The Company reviews goodwill for impairment, at the reporting unit level, annually on October 1 and whenever events or changes in circumstances indicate its carrying value may not be recoverable. In accordance with ASC 350, Intangibles – Goodwill and Other, goodwill is reviewed for impairment utilizing either a qualitative assessment or a quantitative process.

The Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. An entity has an unconditional option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test, which is the option the Company has historically chosen.

For reporting units in which the Company performs the quantitative analysis, the Company compares the carrying value, including goodwill, of each reporting unit with its estimated fair value. If the fair value of the reporting unit exceeds its carrying value, the goodwill is not considered impaired. If the carrying value is greater than the fair value, the difference is recognized as an impairment loss charged to the reporting unit. After an impairment loss is recognized, the adjusted carrying amount of goodwill shall be its new accounting basis.

Long-Lived Assets

Long-lived assets, consisting primarily of intangible assets and property, plant and equipment, are reviewed for impairment whenever facts and circumstances indicate that the carrying amount may not be recoverable. Specifically, this process involves comparing an asset’s carrying value to the estimated undiscounted future cash flows the asset is expected to generate over its remaining life. If this process were to result in the conclusion that the carrying value of a long-lived asset would not be recoverable, a write-down of the asset to fair value would be recorded through a charge to operations. Fair value is determined based upon discounted cash flows or appraisals as appropriate.

Other Assets

The Company capitalizes the cost of computer software developed or obtained for internal use. Capitalized software is amortized using the straight-line method over three to seven years.

Warranties

The Company offers a limited warranty for its products with a coverage period that ranges between one and five years, except that the coverage period for DuraPlate^® trailer panels is ten years. The Company passes through component manufacturers’ warranties to our customers. The Company’s policy is to accrue the estimated cost of warranty coverage at the time of the sale.

Self Insured Liabilities

The Company is self-insured up to specified limits for medical and workers’ compensation coverage. The self-insurance reserves have been recorded to reflect the undiscounted estimated liabilities, including claims incurred but not reported, as well as catastrophic claims as appropriate.

Income Taxes

The Company determines its provision or benefit for income taxes under the asset and liability method. The asset and liability method measures the expected tax impact at current enacted rates of future taxable income or deductions resulting from differences in the tax and financial reporting basis of assets and liabilities reflected in the Consolidated Balance Sheets. Future tax benefits of tax losses and credit carryforwards are recognized as deferred tax assets. Deferred tax assets are reduced by a valuation allowance to the extent management determines that it is more-likely-than-not the Company would not realize the value of these assets.

The Company accounts for income tax contingencies by prescribing a “more-likely-than-not” recognition threshold that a tax position is required to meet before being recognized in the financial statements.

Used Trailer Trade Commitments

The Company may accept trade-in of used trailers when a customer enters into a contract to purchase a new trailer. However, in the contracts for the sale of the new trailers, there is no commitment to repurchase that trailer or a similar trailer in the future. The Company acquired used trailers on trade of $3.2 million, $9.5 million, and $4.6 million in 2018, 2017, and 2016, respectively. As of December 31, 2018, the Company had no outstanding trade commitments and $3.2 million as of December 31, 2017, which also represented the estimated net realizable value of the underlying used trailer. On occasion, the amount of the trade allowance provided for in the used trailer commitments, or cost, may exceed the net realizable value of the underlying used trailer. In these instances, the Company’s policy is to recognize the loss related to these commitments at the time the new trailer revenue is recognized. Net realizable value of used trailers is measured considering market sales data for comparable types of trailers.

Concentration of Credit Risk

Financial instruments that potentially subject us to significant concentrations of credit risk consist principally of cash, cash equivalents and customer receivables. We place our cash and cash equivalents with high quality financial institutions. Generally, we do not require collateral or other security to support customer receivables.

Research and Development

Research and development expenses are charged to Cost of Sales and General and Administrative Expenses in the Consolidated Statements of Operations as incurred and were $8.8 million, $3.9 million and $6.4 million in 2018, 2017 and 2016, respectively.

New Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This update requires lessees to recognize, on the balance sheet, assets and liabilities for the rights and obligations created by leases of greater than twelve months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. We have identified our existing lease contracts and have entered data within the contracts needed for the calculation of the right of use assets and lease liabilities into software to build our repository of lease contracts and to assist us with the accounting entries. This guidance is effective for the Company as of January 1, 2019. The FASB has issued further ASUs related to the standard providing an optional transition method allowing entities to not recast comparative periods. The Company intends to use the optional transition method and, as such, recognize the effects of applying the new standard as a cumulative-effect adjustment to retained earnings as of January 1, 2019. The Company plans to elect the practical expedients upon transition that will retain the lease classification and initial direct costs for any leases that exist prior to adoption of the standard. Wabash will not reassess whether any contracts entered into prior to adoption are leases. On adoption, we currently expect to record right of use assets and lease liabilities in the range of $9.2 million to $10.2 million, based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash, which requires entities to show the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents in the statement of cash flows. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one item on the balance sheet, a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet is required. This guidance was adopted by the Company on January 1, 2018 and was applied retrospectively.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment (“ASU 2017-4”). ASU 2017-4 eliminates Step 2 of the current goodwill impairment test, which requires a hypothetical purchase price allocation to measure goodwill impairment. A goodwill impairment loss will instead be measured at the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the recorded amount of goodwill. The new standard is effective for annual and interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. Early adoption is permitted for annual or interim goodwill impairment testing performed after January 1, 2017. The Company early adopted ASU 2017-04 in the third quarter of 2018. The company recognized a $4.9 million goodwill impairment charge during the three months ended September 30, 2018 (refer to Note 6 for more information).

In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities (“ASU 2017-12”). ASU 2017-12 eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The new standard is effective for fiscal years beginning after December 15, 2018. Early adoption is permitted in any fiscal year or interim period before the effective date. The Company early adopted ASU 2017-12 in the fourth quarter of 2018.

Revenue from Contract with Customer

The Company recognizes revenue from the sale of its products when obligations under the terms of a contract with our customers are satisfied; this occurs with the transfer of control of our products and replacement parts or throughout the completion of service work. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring promised goods or services to a customer and excludes all taxes collected from the customer. Shipping and handling fees are included in Net Sales and the associated costs included in Cost of Sales in the Consolidated Statements of Operations. For shipping and handling costs that take place after the transfer of control, the Company is applying the practical expedient and treating it as a fulfillment cost. Incidental items that are immaterial in the context of the contract are recognized as expense. For performance obligations satisfied over time, which include certain equipment-related sales within our Diversified Products reportable segment that have no alternative use and contain an enforceable right to payment, as well as service work whereby the customer simultaneously receives and consumes the benefits provided, the Company recognizes revenue on the basis of the Company’s efforts or inputs to the satisfaction of these performance obligations, measured by actual total cost incurred to the total estimated costs for each project. Total revenue recognized over time was not material to the consolidated financial statements for all periods presented.

The Company has identified three separate and distinct performance obligations: 1) the sale of a trailer or equipment, 2) the sale of replacement parts, and 3) service work. For trailer, truck body, equipment, and replacement part sales, control is transferred and revenue is recognized from the sale upon shipment to or pick up by the customer in accordance with the contract terms. The Company does not have any material extended payment terms as payment is received shortly after the point of sale. Accounts receivable are recorded when the right to consideration becomes unconditional. The Company does have customers who pay for the product prior to the transfer of control which is recorded as customer deposits in Other Accrued Liabilities as shown in Note 9. Customer deposits are recognized as revenue when the Company performs its obligations under the contract and transfers control of the product.