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v3.25.3

Summary of Significant Accounting Policies and Other Information - Narrative (Details) | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2025 USD ($) boardMember | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) segment boardMember | Sep. 30, 2024 USD ($) | Sep. 18, 2025 | Jul. 30, 2025 USD ($) | Dec. 31, 2024 USD ($) | Aug. 30, 2024 USD ($)
Concentration Risk [Line Items] |  |  |  |  |  |  |  |
Number of board members | boardMember | 4 |  | 4 |  |  |  |  |
Net income | $ 27,616,000 | $ 17,337,000 | $ 97,910,000 | $ 45,992,000 |  |  |  |
Cash flow from operating activities |  |  | $ 28,730,000 | 29,739,000 |  |  |  |
Number of operating segments | segment |  |  | 1 |  |  |  |  |
Restricted cash | 3,680,000 | $ 3,217,000 | $ 3,680,000 | $ 3,217,000 |  |  | $ 3,239,000 |
Inventory raw materials provided by customers | $ 2,800,000 |  | $ 2,800,000 |  |  |  |  |
Weichai America Corp | Power Solutions International, Inc. |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |
Equity method investment, ownership percentage | 46.50% |  | 46.50% |  |  |  |  |
Founders | Power Solutions International, Inc. |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |
Beneficial ownership percentage |  |  |  |  | 6.30% |  |  |
Line of Credit | Revolving Credit Facility | Revolving Credit Agreement |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |
Maximum borrowing capacity (upto) |  |  |  |  |  | $ 135,000,000 |  | $ 120,000,000.0
Contract With Customer |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |
Restricted cash | $ 1,400,000 |  | $ 1,400,000 |  |  |  | $ 1,400,000 |

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