Line of Credit Facility, Unused Capacity, Commitment Fee Threshold, Percentage Of Borrowing Base

No definition available.

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- Definition

Long-Term And Short-Term Debt, Gross

+ References

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Amount of assets pledged to secure a debt instrument.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
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- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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- Details

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Borrowings - Schedule of Warehouse Credit Facilities (Details) - USD ($)	6 Months Ended
	Jun. 30, 2026	Jun. 05, 2026	Jun. 04, 2026	Dec. 31, 2025
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 2,031,583,000			$ 1,860,774,000
Revolving Credit Facility \| Upstart Auto Warehouse Trust 2 \| Variable Interest Entity, Primary Beneficiary
Line of Credit Facility [Line Items]
Total borrowing capacity	150,000,000
Collateral	0			3,000
Outstanding borrowings	$ 0			1,000
Revolving Credit Facility \| Upstart Auto Warehouse Trust 2 \| Variable Interest Entity, Primary Beneficiary \| Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Revolving Credit Facility \| Upstart Auto Warehouse Trust 2 \| Variable Interest Entity, Primary Beneficiary \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.00%
Revolving Credit Facility \| Upstart Loan Trust
Line of Credit Facility [Line Items]
Total borrowing capacity	$ 400,000,000	$ 400,000,000.0	$ 325,000,000.0
Collateral	308,615,000			56,255,000
Outstanding borrowings	$ 177,451,000	$ 175,000,000.0		23,025,000
Revolving Credit Facility \| Upstart Loan Trust \| Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.80%
Revolving Credit Facility \| Upstart Loan Trust \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.40%
Revolving Credit Facility \| Upstart Small Dollar Loan Trust
Line of Credit Facility [Line Items]
Basis spread on variable rate	5.50%
Total borrowing capacity	$ 100,000,000
Collateral	123,475,000			128,973,000
Outstanding borrowings	$ 74,307,000			74,307,000
Commitment fee threshold	75.00%
Revolving Credit Facility \| Warehouse credit facilities
Line of Credit Facility [Line Items]
Total borrowing capacity	$ 650,000,000
Collateral	432,090,000			185,231,000
Outstanding borrowings	$ 251,758,000			$ 97,333,000
Revolving Credit Facility \| Warehouse credit facilities \| Maximum
Line of Credit Facility [Line Items]
Unused commitment fee	1.00%
Revolving Credit Facility \| Un Committed
Line of Credit Facility [Line Items]
Total borrowing capacity	$ 225,000,000.0