Summary of Significant Accounting Policies and Other Information (Policies)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The Company is filing this Form 10-Q for the three months ended March 31, 2020, which contains unaudited consolidated financial statements as of and for the three months ended March 31, 2020 and 2019. The consolidated financial statements include the accounts of Power Solutions International, Inc. and its wholly-owned subsidiaries and majority-owned subsidiaries in which the Company exercises control. The foregoing financial information was prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial reporting. All intercompany balances and transactions have been eliminated in consolidation. Certain information and note disclosures normally included in the Company’s annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying consolidated financial statements should be read in conjunction with, and have been prepared in accordance with accounting policies reflected in, the consolidated financial statements and related notes, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 (“the 2019 Annual Report”), which should be read in conjunction with the disclosures therein. The Company’s significant accounting policies are described in the aforementioned 2019 Annual Report. Included below are certain updates to those policies. The accompanying interim financial information is unaudited; however, the Company believes the financial information reflects all adjustments (consisting of items of a normal recurring nature) necessary for a fair presentation of financial position, results of operations and cash flows in conformity with U.S. GAAP. Operating results for interim periods are not necessarily indicative of annual operating results. The Company operates as one business and geographic operating segment. Operating segments are defined as components of a business that can earn revenue and incur expenses for which discrete financial information is available that is evaluated on a regular basis by the chief operating decision maker (“CODM”). The Company’s CODM is its principal executive officer, who decides how to allocate resources and assess performance. A single management team reports to the CODM, who manages the entire business. The Company’s CODM reviews consolidated statements of operations to make decisions, allocate resources and assess performance, and the CODM does not evaluate the profit or loss from any separate geography or product line.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires that management 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 consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions include the valuation of allowances for uncollectible receivables, inventory reserves, warranty reserves, stock-based compensation, evaluation of goodwill, other intangibles, plant and equipment for impairment, and determination of useful lives of long-lived assets. Actual results could materially differ from those estimates.
Research and Development	Research and Development Research and development (“R&D”) expenses are expensed when incurred. R&D expenses consist primarily of wages, materials, testing and consulting related to the development of new engines, parts and applications.
Inventories	Inventories The Company’s inventories consist primarily of engines and parts. Engines are valued at the lower of cost plus estimated freight-in or net realizable value. Parts are valued at the lower of cost or net realizable value. Net realizable value approximates replacement cost. Cost is principally determined using the first-in, first-out method and includes material, labor and manufacturing overhead. It is the Company’s policy to review inventories on a continuing basis for obsolete, excess and slow-moving items and to record valuation adjustments for such items in order to eliminate non-recoverable costs from inventory. Valuation adjustments are recorded in an inventory reserve account and reduce the cost basis of the inventory in the period in which the reduced valuation is determined. Inventory reserves are established based on quantities on hand, usage and sales history, customer orders, projected demand and utilization within a current or future power system. Specific analysis of individual items or groups of items is performed based on these same criteria, as well as on changes in market conditions or any other identified conditions.
Warranty Costs	Warranty Costs The Company offers a standard limited warranty on the workmanship of its products that in most cases covers defects for a defined period. Warranties for certified emission products are mandated by the U.S. Environmental Protection Agency (the “EPA”) and/or the California Air Resources Board (the “CARB”) and are longer than the Company’s standard warranty on certain emission related products. The Company’s products also carry limited warranties from suppliers. The Company’s warranties generally apply to engines fully manufactured by the Company and to the modifications the Company makes to supplier base products. Costs related to supplier warranty claims are generally borne by the supplier and passed through to the end customer. Warranty estimates are based on historical experience and represent the projected cost associated with the product. A liability and related expense are recognized at the time products are sold. The Company adjusts estimates when it is determined that actual costs may differ from initial or previous estimates.
Recently Issued Accounting Pronouncements - Adopted and Not Yet Adopted	Recently Issued Accounting Pronouncements – Adopted In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. This guidance requires the use of existing accounting guidance applicable to software developed for internal use to be applied to cloud computing service contracts’ implementation costs. The costs capitalized would be amortized over the life of the agreement, including renewal option periods likely to be used. The Company adopted the standard effective January 1, 2020 on a prospective basis. There was no impact on the Company’s financial statements including the related notes as a result of adopting the guidance. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, which both reduces and expands selected disclosure requirements. The principal changes expected to impact the Company’s disclosure are requirements to disclose the range and weighted average of each of the significant unobservable items and the way the weighted average of a range is calculated for items in the “table of significant unobservable inputs.” The guidance also requires disclosure of changes in unrealized gains and losses in other comprehensive income and removes requirements regarding, among other items, disclosure of the valuation process for Level 3 measurements. The Company adopted the guidance on January 1, 2020. There was no impact on the Company’s financial statements including the related notes as a result of adopting the guidance. In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other: Simplifying the Test for Goodwill Impairment, which eliminated the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value. The Company adopted the guidance on January 1, 2020 on a prospective basis. There was no impact on the Company’s financial statements including the related notes as a result of adopting the guidance. Recently Issued Accounting Pronouncements – Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments, which applies primarily to the Company’s accounts receivable impairment loss allowances. The guidance provides a revised model whereby the current expected credit losses are used to compute impairment of financial instruments. The new model requires evaluation of historical experience and various current and expected factors, which may affect the estimated amount of losses and requires determination of whether the affected financial instruments should be grouped in units of account. The guidance, as originally issued, was effective for fiscal years beginning after December 15, 2019. In November 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Effective Dates, which deferred the effective dates of these standards for certain entities. Based on the guidance, the effective date of ASU 2016-13 is deferred for the Company until fiscal year 2023. The Company currently plans to adopt the guidance on January 1, 2023 when it becomes effective. The Company is continuing to assess the impact of the standard on its financial statements.