| Pay vs Performance Disclosure - USD ($) | 12 Months Ended |
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 |
| Pay vs Performance Disclosure [Table] | | | |
| Pay vs Performance [Table Text Block] | Value of Initial Fixed $100 Performance Year Summary Compensation Table Total for Principal Executive Officer (1) Compensation Actually Paid to Principal Executive Officer (1) Average Summary Compensation Table Total for Non-PEO Named Executive Officers (1) Average Compensation Actually Paid to Non-PEO Named Executive Officers (1) Total Shareholder Return (2) Peer Group Total Shareholder Return (2) Net Income (Loss) Company-Selected Measure —Adjusted Net Revenue 2022 $ 12,893,293 $ (121,490,627) $ 10,363,699 $ (25,896,259) $ 20.35 $ 77.11 $ (320,407) $ 1,540,492 2021 $ 102,998,110 $ 119,107,305 $ 19,026,864 $ 20,461,726 $ 70.42 $ 114.30 $ (483,937) $ 1,010,325 2020 $ 53,533,739 $ 92,386,353 $ 11,039,231 $ 17,084,857 n/a n/a $ (224,053) $ 621,207 | | |
| Company Selected Measure Name | Adjusted net revenue | | |
| Named Executive Officers, Footnote [Text Block] | Mr. Noto is represented as the principal executive officer (“PEO”) for each of the performance years presented. For the 2022 performance year, the non-PEO named executive officers (“non-PEO NEOs”) include Messrs. Lapointe, Borton, Rishel and Webster and Ms. Gill. For the 2021 performance year, the non-PEO NEOs include Messrs. Lapointe and White and Mses. Gill and Nuckles. For the 2020 performance year, the non-PEO NEOs include Mr. Lapointe and Mses. Gill, Nuckles and Renz. | | |
| Peer Group Issuers, Footnote [Text Block] | Total Shareholder Return (“TSR”) is cumulative for the measurement periods beginning on June 1, 2021 (the date our common stock commenced trading on the Nasdaq Global Select Market) and ending on the last day in 2022 and 2021, calculated in accordance with Item 201(e) of Regulation S-K. “Peer Group” represents the Nasdaq Composite index for the years disclosed in the table. No information is provided for 2020, as our common stock was not publicly traded. | | |
| PEO Total Compensation Amount | $ 12,893,293 | $ 102,998,110 | $ 53,533,739 |
| PEO Actually Paid Compensation Amount | $ (121,490,627) | 119,107,305 | 92,386,353 |
| Adjustment To PEO Compensation, Footnote [Text Block] | The Compensation Committee does not utilize CAP as the basis for making compensation decisions. The calculation of CAP requires that we make adjustments to amounts previously reported in the Summary Compensation Table for the years presented. The SEC’s valuation and calculation methods for CAP differ from those required in the Summary Compensation Table. The table below summarizes compensation values presented in the Summary Compensation Table and the adjusted values required to reconcile these values to the CAP presented above. The amounts shown below for non-PEO NEOs for each year represents an average of all non-PEO NEOs. CAP to the PEO and non-PEO NEOs represents Summary Compensation Table total compensation adjusted by the following amounts: Reconciliation of Summary Compensation Table Total to Compensation Actually Paid (1) Summary Compensation Table Total Summary Compensation Table Total (2) Plus Fair Value of Change in Fair Value of Equity Awards Granted in Prior Plus Fair Value of Equity Awards Granted and Vested in Covered Year Less Fair Value of Equity Awards Reported in the Summary Compensation Table in the Covered Year Change in Fair Value of Equity Awards Granted in Prior Less Fair Value of Equity Awards Granted in Prior Years and Forfeited in Covered Year (3) Compensation Actually Paid (4) 2022 – PEO $ 12,893,293 $ 4,684,963 $ (99,602,444) $ — $ (9,400,414) $ (30,066,025) $ — $ (121,490,627) 2022 – non-PEO NEOs 10,363,699 6,032,115 (11,117,288) 927,430 (9,026,274) (3,934,694) (19,141,247) (25,896,259) 2021 – PEO $ 102,998,110 $ 46,631,650 $ 45,712,042 $ — $ (101,187,079) $ 24,952,582 $ — $ 119,107,305 2021 – non-PEO NEOs 19,026,864 13,477,008 831,998 2,002,816 (17,674,364) 2,797,404 — 20,461,726 2020 – PEO $ 53,533,739 $ 56,968,264 $ 27,737,216 $ 2,406,701 $ (52,118,397) $ 3,858,830 $ — $ 92,386,353 2020 – non-PEO NEOs 11,039,231 13,250,711 1,257,859 1,297,375 (10,017,783) 257,464 — 17,084,857 __________________ (1) Fair values are calculated in accordance with ASC 718 as of the end of the respective year, other than awards that vest in the covered year, which are valued as of the applicable vesting dates. (2) Reflects the total compensation amount for the PEO and average total compensation amount for the non-PEO NEOs as reported in the Summary Compensation Table for each year presented. (3) Reflects awards that failed to meet vesting conditions during the covered year. (4) Reflects the actual CAP for the PEO and average CAP for the non-PEO NEOs. | | |
| Non-PEO NEO Average Total Compensation Amount | $ 10,363,699 | 19,026,864 | 11,039,231 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ (25,896,259) | 20,461,726 | 17,084,857 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | The Compensation Committee does not utilize CAP as the basis for making compensation decisions. The calculation of CAP requires that we make adjustments to amounts previously reported in the Summary Compensation Table for the years presented. The SEC’s valuation and calculation methods for CAP differ from those required in the Summary Compensation Table. The table below summarizes compensation values presented in the Summary Compensation Table and the adjusted values required to reconcile these values to the CAP presented above. The amounts shown below for non-PEO NEOs for each year represents an average of all non-PEO NEOs. CAP to the PEO and non-PEO NEOs represents Summary Compensation Table total compensation adjusted by the following amounts: Reconciliation of Summary Compensation Table Total to Compensation Actually Paid (1) Summary Compensation Table Total Summary Compensation Table Total (2) Plus Fair Value of Change in Fair Value of Equity Awards Granted in Prior Plus Fair Value of Equity Awards Granted and Vested in Covered Year Less Fair Value of Equity Awards Reported in the Summary Compensation Table in the Covered Year Change in Fair Value of Equity Awards Granted in Prior Less Fair Value of Equity Awards Granted in Prior Years and Forfeited in Covered Year (3) Compensation Actually Paid (4) 2022 – PEO $ 12,893,293 $ 4,684,963 $ (99,602,444) $ — $ (9,400,414) $ (30,066,025) $ — $ (121,490,627) 2022 – non-PEO NEOs 10,363,699 6,032,115 (11,117,288) 927,430 (9,026,274) (3,934,694) (19,141,247) (25,896,259) 2021 – PEO $ 102,998,110 $ 46,631,650 $ 45,712,042 $ — $ (101,187,079) $ 24,952,582 $ — $ 119,107,305 2021 – non-PEO NEOs 19,026,864 13,477,008 831,998 2,002,816 (17,674,364) 2,797,404 — 20,461,726 2020 – PEO $ 53,533,739 $ 56,968,264 $ 27,737,216 $ 2,406,701 $ (52,118,397) $ 3,858,830 $ — $ 92,386,353 2020 – non-PEO NEOs 11,039,231 13,250,711 1,257,859 1,297,375 (10,017,783) 257,464 — 17,084,857 __________________ (1) Fair values are calculated in accordance with ASC 718 as of the end of the respective year, other than awards that vest in the covered year, which are valued as of the applicable vesting dates. (2) Reflects the total compensation amount for the PEO and average total compensation amount for the non-PEO NEOs as reported in the Summary Compensation Table for each year presented. (3) Reflects awards that failed to meet vesting conditions during the covered year. (4) Reflects the actual CAP for the PEO and average CAP for the non-PEO NEOs. | | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | The following graph compares the compensation actually paid to our PEO, the average of the compensation actually paid to our non-PEO NEOs and TSR for the Company and the Nasdaq Composite Index, which is cumulative based on the performance of a $100 investment from June 1, 2021 (the date our common stock commenced trading on the Nasdaq Global Select Market) to the last day in each of 2021 and 2022. The graph below shows a connection between compensation actually paid and TSR. | | |
| Compensation Actually Paid vs. Net Income [Text Block] | The following graph compares the compensation actually paid to our PEO, the average of the compensation actually paid to our non-PEO NEOs and the Company’s net income (loss). | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | The following graph compares the compensation actually paid to our PEO, the average of the compensation actually paid to our non-PEO NEOs and the Company’s adjusted net revenue. | | |
| Total Shareholder Return Vs Peer Group [Text Block] | The following graph compares the compensation actually paid to our PEO, the average of the compensation actually paid to our non-PEO NEOs and TSR for the Company and the Nasdaq Composite Index, which is cumulative based on the performance of a $100 investment from June 1, 2021 (the date our common stock commenced trading on the Nasdaq Global Select Market) to the last day in each of 2021 and 2022. The graph below shows a connection between compensation actually paid and TSR. | | |
| Total Shareholder Return Amount | $ 20.35 | 70.42 | |
| Peer Group Total Shareholder Return Amount | 77.11 | 114.30 | |
| Net Income (Loss) | $ (320,407,000) | $ (483,937,000) | $ (224,053,000) |
| Company Selected Measure Amount | 1,540,492,000 | 1,010,325,000 | 621,207,000 |
| PEO Name | Mr. Noto | | |
| Additional 402(v) Disclosure [Text Block] | Our NEOs’ target total compensation is heavily weighted towards short and long-term performance. The majority of our NEOs’ target annual total direct compensation is both variable in nature and "at-risk". Adjusted net revenue is one of the primary measures in our performance-based Annual Cash Bonus Plan. Our long-term incentives are time-based RSUs, in addition to PSUs that we grant from time to time. The compensation actually paid to our NEOs largely reflects the volatility in the Company’s stock price over the period of time covered in the table. Adjusted net revenue (financial performance measure and Company-selected measure) Adjusted net revenue is a non-GAAP measure defined as total net revenue, adjusted to exclude the fair value changes in servicing rights and residual interests classified as debt due to valuation inputs and assumptions changes, as they are non-cash charges that are not realized during the period, and therefore positive or negative changes do not impact the cash available to fund our operations. This measure helps provide our management with an understanding of the net revenue available to finance our operations and helps management better decide on the proper expenses to authorize for each of our operating segments, to ultimately help achieve target contribution profit margins. Therefore, the measure of adjusted net revenue serves as both the starting point for how we think about the liquidity generated from our operations and also the starting point for our annual financial planning, the latter of which focuses on the cash we expect to generate from our operating segments to help fund the current year’s strategic objectives. Refer to Appendix B for additional discussion of adjusted net revenue, as well as a reconciliation to the most directly comparable GAAP measure. Adjusted EBITDA (financial performance measure) Adjusted EBITDA is defined as net income (loss), adjusted to exclude, as applicable: (i) corporate borrowing-based interest expense (our adjusted EBITDA measure is not adjusted for warehouse or securitization-based interest expense, nor deposit interest expense and finance lease liability interest expense, as these are not direct operating expenses), (ii) income tax expense (benefit), (iii) depreciation and amortization, (iv) share-based expense (inclusive of equity-based payments to non-employees), (v) impairment expense (inclusive of goodwill impairment and property, equipment and software abandonments), (vi) transaction-related expenses, (vii) fair value changes in warrant liabilities, and (viii) fair value changes in each of servicing rights and residual interests classified as debt due to valuation assumptions. We believe adjusted EBITDA provides a useful measure for period-over-period comparisons of our business, as it removes the effects of certain non-cash items and certain charges that are not indicative of our core operating performance or results of operations. It is also a measure that management relies upon to evaluate cash flows generated from operations, and therefore the extent of additional capital, if any, required to invest in strategic initiatives. Refer to Appendix B for additional discussion of adjusted EBITDA, as well as a reconciliation to the most directly comparable GAAP measure. Incremental net income margin (financial performance measure) Incremental net income margin is calculated as the change in net loss year over year divided by the change in adjusted net revenue year over year. We view incremental net income margin as indicative of the level of net income margins we can deliver long term, given ongoing investments in the business. New members (nonfinancial performance measure) We refer to our customers as “members”. We define a member as someone who has a lending relationship with us through origination and/or ongoing servicing, opened a financial services account, linked an external account to our platform or signed up for our credit score monitoring service. Once someone becomes a member, they are always considered a member unless they violate our terms of service. We view members as an indication not only of the size and a measurement of growth of our business, but also as a measure of the significant value of the data we have collected over time. “New members” represents the increase in members during the period. New products (nonfinancial performance measure) Total products refers to the aggregate number of lending and financial services products that our members have selected on our platform since our inception through the reporting date, whether or not the members are still registered for such products. Total products is a primary indicator of the size and reach of our Lending and Financial Services segments. Management relies on total products metrics to understand the effectiveness of our member acquisition efforts and to gauge | | |
| Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted net revenue | | |
| Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted EBITDA | | |
| Measure [Axis]: 3 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Incremental net income margin | | |
| Measure [Axis]: 4 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | New members | | |
| Measure [Axis]: 5 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | New products | | |
| PEO [Member] | Equity Awards Granted During The Year, Unvested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ 4,684,963 | $ 46,631,650 | $ 56,968,264 |
| PEO [Member] | Equity Awards Granted In Prior Years, Unvested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (99,602,444) | 45,712,042 | 27,737,216 |
| PEO [Member] | Equity Awards Granted During The Year, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | 0 | 2,406,701 |
| PEO [Member] | Equity Awards Reported Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (9,400,414) | (101,187,079) | (52,118,397) |
| PEO [Member] | Equity Awards Granted In Prior Years, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (30,066,025) | 24,952,582 | 3,858,830 |
| PEO [Member] | Equity Awards Granted In Prior Years, Failed To Meet Vesting Conditions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Equity Awards Granted During The Year, Unvested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 6,032,115 | 13,477,008 | 13,250,711 |
| Non-PEO NEO [Member] | Equity Awards Granted In Prior Years, Unvested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (11,117,288) | 831,998 | 1,257,859 |
| Non-PEO NEO [Member] | Equity Awards Granted During The Year, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 927,430 | 2,002,816 | 1,297,375 |
| Non-PEO NEO [Member] | Equity Awards Reported Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (9,026,274) | (17,674,364) | (10,017,783) |
| Non-PEO NEO [Member] | Equity Awards Granted In Prior Years, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (3,934,694) | 2,797,404 | 257,464 |
| Non-PEO NEO [Member] | Equity Awards Granted In Prior Years, Failed To Meet Vesting Conditions [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ (19,141,247) | $ 0 | $ 0 |
