v3.26.1
Cover Page - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Apr. 23, 2026
Jun. 30, 2025
Document Information [Line Items]      
Document Type 10-K/A    
Document Annual Report true    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Entity File Number 001-35944    
Entity Registrant Name POWER SOLUTIONS INTERNATIONAL, INC.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 33-0963637    
Entity Address, Address Line One 201 Mittel Drive    
Entity Address, City or Town Wood Dale    
Entity Address, State or Province IL    
Entity Address, Postal Zip Code 60191    
City Area Code 630    
Local Phone Number 350-9400    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 717.9
Entity Common Stock, Shares Outstanding   23,050,450  
Entity Central Index Key 0001137091    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Amendment Flag true    
Amendment Description This Amendment No. 1 (this “Amendment”) on Form 10-K/A amends the Annual Report on Form 10-K for the year ended December 31, 2025 of Power Solutions International, Inc. (“PSI” or the “Company”) filed with the Securities and Exchange Commission (the “SEC”) on March 2, 2026 (the “Original 10-K”) to include the information required by Items 10 through 14 of Part III (the “Part III Disclosure”) of the Original 10-K. This information was previously omitted from the Original 10-K in reliance on General Instruction G(3) to Form 10-K, which permits the information in the above referenced items to be incorporated in the Form 10-K by reference to the Company’s definitive proxy statement if such statement is filed no later than 120 days after the Company’s fiscal year-end. The information included herein as required by the Part III Disclosure is more limited than what is required to be included in the definitive proxy statement to be filed in connection with PSI’s 2025 Annual Meeting of Stockholders. Accordingly, the definitive proxy statement to be filed at a later date will include additional information related to the topics herein and additional information not required by the Part III Disclosure. Pursuant to the SEC rules, Part IV, Item 15 has also been amended to contain the currently dated certificates from the Company’s principal executive and financial officers pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. The certificates of the Company’s principal executive and financial officers are attached to this Amendment as Exhibits 31.3 and 31.4. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. Additionally, PSI is not including the certificates under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment. Except for the information described above, the Company has not modified or updated disclosures provided in the Original 10-K in this Amendment. Accordingly, this Amendment does not reflect events occurring after the filing of the Original 10-K or modify or update those disclosures affected by subsequent events, except as noted herein. Information not affected by this Amendment is unchanged and reflects the disclosures made at the time the Original 10-K was filed.    
ICFR Auditor Attestation Flag true    
Documents Incorporated by Reference None.    
Document Financial Statement Error Correction [Flag] false    
Title of 12(b) Security Common Stock, par value $0.001 per share    
Trading Symbol PSIX    
Security Exchange Name NASDAQ