Purchase of Convertible Note	6 Months Ended
	Jun. 30, 2022
Convertible Notes Payable [Abstract]
Purchase of Convertible Note	Purchase of Convertible NoteOn July 15, 2021, XL Fleet made an investment of $3,000 into eNow, a developer of solar and battery power systems that is developing fully-electric transport refrigeration units (“eTRUs”) for commercial trailers. In exchange for the investment, eNow issued to the Company a convertible debenture (the “eNow Convertible Note”) dated July 15, 2021 (the “Issuance Date”) in the original principal amount of $3,000, at the rate of 8% per annum and due on December 31, 2022. The investment was classified as an available-for-sale security. After reviewing the status of eNow’s financial condition on December 31, 2021, the Company determined that the investment in the eNow Convertible Note was fully impaired and as such, on such date, recorded an impairment charge of $3,000. Under certain circumstances, the eNow Convertible Note could be converted into Series B preferred stock.In addition to the terms described above, on July 15, 2021 (“Effective Date”), XL Fleet entered into a Development and Supply Agreement (the “Development and Supply Agreement”) with eNow, whereby XL Fleet was made the exclusive provider of high voltage batteries and associated power systems for use in eNow eTRUs. The Company considered the existence of adverse conditions regarding the global supply chain crisis (electronic hardware, lithium ion cells and batteries) that causes further impediments to eNow being able to execute on its business plan. XL Fleet evaluated the supply chain issues, specifically the lack of availability of batteries from third party suppliers. During the three months ended December 31, 2021, the supply chain issues worsened, and in particular the lack of availability of batteries from third party suppliers. These worsened conditions, in the Company’s opinion, negatively impacted eNow’s prospects and financial condition. In January 2022, due to the ongoing supply chain issues, the Company notified eNow of its intention to terminate the Development and Supply Agreement (See Note 10). The arrangement was terminated in the second quarter of 2022. As part of the termination of the arrangement, the Company agreed to the conversion of the eNow Convertible Note into common shares of eNow at a rate of $1.1658 per share. As noted above, these shares have no book value as the investment in the eNow Convertible Note was fully impaired in the fourth quarter of 2021.