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Stock-based Compensation - Additional Information (Details) - USD ($) |  |  |  |  |  |  |  | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 02, 2024 | Nov. 07, 2023 | Jan. 03, 2023 | Jan. 03, 2022 | Aug. 22, 2016 | Aug. 15, 2015 | Jun. 26, 2015 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Nov. 30, 2023 | Dec. 08, 2022 | Dec. 31, 2020 | Oct. 16, 2017 | Jun. 21, 2017 | Dec. 31, 2006
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | $ 113,456,000 |  | $ 33,682,000 | $ 77,710,000 |  |  |  |  |  |
Capitalized website development and internal-use software costs excluded from stock-based compensation expense |  |  |  |  |  |  |  | 5,472,000 |  | 4,468,000 | 3,247,000 |  |  |  |  |  |
Income tax benefit from stock-based compensation expense |  |  |  |  |  |  |  | 5,353,000 |  | 5,441,000 | 5,301,000 |  |  |  |  |  |
Employee tax withholding requirements for net share settlements of equity awards |  |  |  |  |  |  |  | 15,729,000 |  | 16,025,000 | 15,388,000 |  |  |  |  |  |
Payment of withholding taxes on net share settlements of restricted stock units |  |  |  |  |  |  |  | $ 15,597,000 |  | 16,022,000 | 15,388,000 |  |  |  |  |  |
Number of shares repurchased and retired |  |  |  |  |  |  |  | 11,076,755 |  |  |  |  |  |  |  |  |
Share repurchased and retired, value |  |  |  |  |  |  |  | $ 204,127,000 |  |  |  |  |  |  |  |  |
Share repurchased and retired at average cost price per share |  |  |  |  |  |  |  | $ 18.43 |  |  |  |  |  |  |  |  |
Redeemable noncontrolling interest |  |  |  |  |  |  |  | $ 0 |  | $ 36,749,000 | $ 162,808,000 |  |  | $ 0 |  |  |
Deemed dividend on redemption of noncontrolling interest |  |  |  |  |  |  |  | $ 5,838,000 |  |  |  |  |  |  |  |  |
Share repurchase program effective date |  | Jan. 01, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share repurchase program expiration date |  | Dec. 31, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Stock Option |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of options granted in period |  |  |  |  |  |  |  | 0 |  | 30,266 | 619,618 |  |  |  |  |  |
Aggregate intrinsic value for options exercised |  |  |  |  |  |  |  | $ 229,000 | [1] | $ 3,774,000 | $ 6,027,000 |  |  |  |  |  |
Unrecognized stock-based compensation expense related to unvested stock options |  |  |  |  |  |  |  | $ 2,623,000 |  |  |  |  |  |  |  |  |
Unrecognized stock-based compensation expense, expected period for recognition |  |  |  |  |  |  |  | 1 year 3 months 18 days |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | $ 2,386,000 |  | $ 2,553,000 | $ 2,471,000 |  |  |  |  |  |
RSUs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units granted in period |  |  |  |  |  |  |  | 4,133,865 |  |  |  |  |  |  |  |  |
Unvested units |  |  |  |  |  |  |  | 5,687,711 |  | 4,484,291 |  |  |  |  |  |  |
Weighted average grant date fair value of RSUs granted |  |  |  |  |  |  |  | $ 17.47 |  | $ 28.94 | $ 33.83 |  |  |  |  |  |
Number of RSUs vested and settled during period |  |  |  |  |  |  |  |  |  | 1,649,294 | 1,575,206 |  |  |  |  |  |
Total fair value of RSUs vested |  |  |  |  |  |  |  |  |  | $ 55,136,000 | $ 52,423,000 |  |  |  |  |  |
Unrecognized stock-based compensation expense related to RSUs |  |  |  |  |  |  |  | $ 108,714,000 |  |  |  |  |  |  |  |  |
Unrecognized stock-based compensation expense, expected period for recognition |  |  |  |  |  |  |  | 2 years 6 months |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | $ 55,527,000 |  | 52,224,000 | 52,916,000 |  |  |  |  |  |
Number of units vested in period |  |  |  |  |  |  |  | 2,440,510 |  |  |  |  |  |  |  |  |
Number of units forfeited in period |  |  |  |  |  |  |  | 489,935 |  |  |  |  |  |  |  |  |
CO Incentive Units and Subject Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | $ 26,552,000 |  | $ (21,095,000) | $ 22,323,000 |  |  |  |  |  |
(Increase) decrease in stock-based compensation expense |  |  |  |  |  |  |  | (47,647,000) |  |  |  |  |  |  |  |  |
Noncontrolling Interest Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | 28,991,000 |  |  |  |  |  |  |  |  |
(Increase) decrease in stock-based compensation expense |  |  |  |  |  |  |  | $ 28,991,000 |  |  |  |  |  |  |  |  |
Class A Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee tax withholding requirements and option costs due to net share settlement |  |  |  |  |  |  |  | 840,995 |  | 566,267 | 527,237 |  |  |  |  |  |
Class A Common Stock | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate share repurchase price |  | $ 250,000,000 |  |  |  |  |  |  |  |  |  |  | $ 250,000,000 |  |  |  |
2020 CO Plan | Incentive Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  | 485,714 |  |  |  |  |  |  |  |  |
Number of units granted in period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
Number of shares available for issuance during period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
Accelerated and redeemed units |  |  |  |  |  |  |  | 142,857 |  |  |  |  |  |  |  |  |
Unvested units |  |  |  |  |  |  |  | 0 |  | 342,857 |  |  |  |  |  |  |
Unrecognized stock based compensation expense related to unvested units |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  |  |  |  | $ 1,229,000 |  |  |  |  |  |
Number of units vested in period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
Number of units forfeited in period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
2020 CO Plan | Subject Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unrecognized stock based compensation expense related to unvested units |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |  |
Vesting Agreement | Subject Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock options, granted |  |  |  |  |  |  |  | 0 |  | 0 |  |  |  |  |  |  |
Number of shares available for issuance during period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
Units issued and unvested |  |  |  |  |  |  |  | 0 |  | 288,395 |  |  |  |  |  |  |
Number of units vested in period |  |  |  |  |  |  |  | 0 |  | 144,197 |  |  |  |  |  |  |
Number of units forfeited in period |  |  |  |  |  |  |  | 0 |  | 0 |  |  |  |  |  |  |
2021 CO Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  | 228,571 |  |  |  |  |
2021 CO Plan | Incentive Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  | 228,571 |  |  |  |  |  |  |  |  |
Number of shares available for issuance during period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
2021 CO Plan | Subject Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares available for issuance during period |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |
2006 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock options, granted |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
Number of units granted in period |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
2006 Plan | Class B Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,444,668
2015 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  | 603,436 |  |  |  |  |  |  |  |  |  |
Term of authorized shares |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |  |
Award expiration date |  |  |  |  | Aug. 21, 2026 |  |  |  |  |  |  |  |  |  |  |  |
Equity Incentive Plan, plan modification, description and terms |  |  |  |  |  |  |  | (1) the number of shares of Class A common stock was increased, on a share for share basis, by the number of shares of Class B common stock that were (a) subject to outstanding options granted under the 2006 Plan that expired, terminated, or were canceled for any reason without having been exercised, (b) surrendered in payment of the exercise price of outstanding options granted under the 2006 Plan, or (c) withheld in satisfaction of tax withholding upon exercise of outstanding options granted under the 2006 Plan, and the number of shares of Class B common stock reserved under the amended and restated 2015 Plan was decreased, on a corresponding share for share basis, (2) no new awards of Class B common stock could be granted under the amended and restated 2015 Plan, and (3) except with respect to outstanding options granted under the 2006 Plan that were exercised on or after the date of the amendment and restatement, no Class B common stock could be issued under the 2015 Plan. |  |  |  |  |  |  |  |  |
2015 Plan | Class B Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,161,644 |
Number of additional shares authorized |  |  |  |  | 802,562 |  |  |  |  |  |  |  |  |  |  |  |
2015 Plan | Class B Common Stock | Employee Stock Option |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares called by each instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 |
2015 Plan | Class B Common Stock | RSUs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares called by each instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 |
2015 Plan | Class A Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,181,740 |
Number of additional shares authorized |  |  |  |  | 618,691 |  |  |  |  |  |  |  |  |  |  |  |
2015 Plan | Class A Common Stock | Employee Stock Option |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares called by each instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |
2015 Plan | Class A Common Stock | RSUs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares called by each instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |
2017 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of additional shares authorized |  |  | 4,065,466 | 4,070,921 |  |  |  | 6,000,000 |  |  |  |  |  |  |  |  |
Equity incentive plan, issuance of additional shares, description and terms |  |  |  |  |  |  |  | Unless determined otherwise by the Compensation Committee of the Board, as of the first trading day of January of each calendar year during the term of the 2017 Plan (excluding any extensions), eligible beginning with calendar year 2019, an additional number of shares of Class A common stock will be added to the number of shares of the Company’s Class A common stock authorized to be issued or transferred under the 2017 Plan and the number of shares authorized to be issued or transferred pursuant to incentive stock options, equal to 4% of the total number of shares of Class A common stock outstanding on the last trading day in December of the immediately preceding calendar year, or 6,000,000 shares, whichever is less, or such lesser amount as determined by the Board (the “Evergreen Increase”). The Compensation Committee of the Board determined to not effectuate the Evergreen Increase that was otherwise scheduled to have occurred on each of January 2, 2019, January 2, 2020, and January 4, 2021. On January 3, 2022, an additional 4,070,921 shares of the Company's Class A Common Stock was authorized to be issued or transferred under the 2017 Plan pursuant to the Evergreen Increase. On January 3, 2023, an additional 4,065,466 shares of the Company's Class A Common Stock was authorized to be issued or transferred under the 2017 Plan pursuant to the Evergreen Increase. On January 2, 2024, an additional 3,687,010 shares of the Company's Class A Common Stock was authorized to be issued or transferred under the 2017 Plan pursuant to the Evergreen Increase. |  |  |  |  |  |  |  |  |
2017 Plan | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of additional shares authorized | 3,687,010 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2017 Plan | Class A Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity incentive plan, additional shares authorized percentage |  |  |  |  |  |  |  | 4.00% |  |  |  |  |  |  |  |  |
Number of shares available for issuance during period |  |  |  |  |  |  |  | 6,236,628 |  |  |  |  |  |  |  |  |
2017 Plan | Class A Common Stock | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12,300,000 |  |
2017 Plan | Class A Common Stock | Awarded Under 2017 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7,800,000 |  |
2017 Plan | Class A Common Stock | Awarded Under 2015 Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares authorized for issuances |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4,500,000 |  |
2023 CarOffer Transaction | CO Incentive Units and Subject Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  |  |  | $ 20,655,000 |  |  |  |  |  |  |  |  |
[1] | As of December 31, 2023 and 2022, the aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of common stock on December 31, 2023 and 2022, respectively, or the date of exercise, as appropriate, and the exercise price of the underlying options.

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