Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	[1]	$ 1,936,054	$ 1,820,455
Liabilities	[1]	1,263,619	1,013,377
Net Assets		672,435	807,078	$ 300,252	$ (61,688)
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		984,481	342,025
Liabilities		337,830	49,314
Net Assets		646,651	292,711
Variable Interest Entity, Not Primary Beneficiary | Securitizations and other
Variable Interest Entity [Line Items]
Assets		364,013	217,321
Liabilities		265,040	160,248
Net Assets		98,973	57,073
Maximum Exposure to Losses		$ 13,311	$ 15,503

[1] The following table presents information on assets and liabilities related to variable interest entities (“VIEs”) that are consolidated by Upstart Holdings, Inc. at December 31, 2021 and December 31, 2022. The assets in the table below may only be used to settle obligations of consolidated VIEs and are in excess of those obligations. The holders of the beneficial interests do not have recourse to the general credit of Upstart Holdings, Inc. The assets and liabilities in the table below include third-party assets and liabilities of consolidated VIEs and exclude intercompany balances that eliminate in consolidation. December 31,December 31,20212022AssetsCash$7,700 $838 Restricted cash79,561 13,147 Loans (at fair value)245,972 958,822  Other assets (includes $7,571 and $2,244 at fair value as of December 31, 2021 and December 31, 2022, respectively) 8,792 11,674 Total assets$342,025 $984,481 LiabilitiesBorrowings$48,536 $336,452 Accrued expenses and other liabilities778 1,378 Total liabilities49,314 337,830 Total net assets$292,711 $646,651