Guarantees, Commitments and Contingencies	9 Months Ended
Guarantees, Commitments and Contingencies	Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]
Guarantees, Commitments and Contingencies	Guarantees, Commitments and Contingencies The Company provides certain guarantees to Sellers in the Marketplace in the ordinary course of business, which are accounted for under ASC 460 - Guarantees as a general guarantee. Vehicle Condition Guarantees – Sellers must attach a vehicle condition report in the Marketplace for every auction; this vehicle condition report is used by Buyers to inform bid decisions. The Company offers guarantees to Sellers in qualifying situations where the Company performed a vehicle inspection and prepared the vehicle condition report. Sellers pay an additional fee in exchange for this guarantee. Such guarantees provide Sellers protection from paying remedies to Buyers related to a Buyer’s claim that the vehicle condition report did not accurately portray the condition of the vehicle purchased on the Marketplace. These guarantee agreements provide the Company with the right to retain proceeds from the subsequent liquidation of vehicles covered under the guarantees. The guarantees are typically provided for 10 days after the successful sale of the vehicle on the Marketplace. The fair value of vehicle condition guarantees issued is estimated based on historical results and other qualitative factors. Vehicle condition guarantee revenue is recognized on the earlier of the guarantee expiration date or the guarantee settlement date. The maximum potential payment is the sale price of the vehicle. The total sale price of vehicles for which there was an outstanding guarantee was approximately $269.8 million and approximately $161.7 million at September 30, 2025 and December 31, 2024, respectively. The carrying amount of the liability presented in Accrued other liabilities on the Condensed Consolidated Balance Sheets was $2.5 million and $1.4 million at September 30, 2025 and December 31, 2024, respectively. Other Price Guarantees – The Company provides Sellers with a price guarantee for vehicles to be sold on the Marketplace from time to time. If a vehicle sells below the guaranteed price, the Company is responsible for paying the Seller the difference between the guaranteed price and the final sale price. The term of the guarantee is typically less than one week. No material unsettled price guarantees existed at September 30, 2025 and December 31, 2024. Litigation – The Company and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings and matters in which claims for monetary damages are asserted. On an on-going basis management, after consultation with legal counsel, assesses the Company's liabilities and contingencies in connection with such proceedings. For those matters where it is probable that the Company will incur losses and the amounts of the losses can be reasonably estimated, the Company records an expense and corresponding liability in its condensed consolidated financial statements. To the extent pending or threatened litigation could result in exposure in excess of the recorded liability, the amount of such excess is not currently estimable. ACV was a member of a class action lawsuit which sought damages from one of the Company's data services vendors. During September 2025, ACV was awarded a total of $7.9 million from the settlement of this class action lawsuit. Of this total settlement, $7.6 million is included as a reduction in marketplace and service cost of revenue in the Condensed Consolidated Statements of Operations for both the three and nine months ended September 30, 2025. Based on the payment terms provided in the settlement, $6.4 million is included in other current assets and $1.5 million is included in other assets in the Condensed Consolidated Balance Sheet at September 30, 2025.