XML 79 R69.htm IDEA: XBRL DOCUMENT
v3.21.1

Leases - Narrative (Details) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2021 USD ($) optionToExtend
Leases [Abstract] |
Number of options to renew | optionToExtend | 2
Renewal term | 5 years
Letter of credit outstanding | $ | $ 2.0

X
- Definition Lessee, Operating Lease, Number Of Renewal Options + References No definition available. + Details
Name: | upst_LesseeOperatingLeaseNumberOfRenewalOptions
Namespace Prefix: | upst_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant