Borrowings - Asset-backed Notes (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Current balance	$ 2,118,786	$ 2,387,674
Asset-Backed Notes
Debt Instrument [Line Items]
Original Balance	2,754,412	2,754,412
Current balance	2,118,786	2,387,674
Asset-Backed Notes | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	2,834,687	2,834,687
Asset-Backed Notes | Current Collateral
Debt Instrument [Line Items]
Collateral balance	2,384,331	2,706,900
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-3)
Debt Instrument [Line Items]
Original Balance	300,000	300,000
Current balance	$ 211,046	$ 285,218
Weighted average interest rate	8.79%	8.43%
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-3) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 310,993	$ 310,993
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-3) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	235,480	301,967
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-2)
Debt Instrument [Line Items]
Original Balance	400,000	400,000
Current balance	$ 217,410	$ 313,689
Weighted average interest rate	7.52%	7.03%
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-2) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 410,212	$ 410,212
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-2) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	243,818	344,218
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-A)
Debt Instrument [Line Items]
Original Balance	400,000	400,000
Current balance	$ 384,237	$ 380,313
Weighted average interest rate	5.44%	5.44%
Original revolving period	2 years	2 years
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-A) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 410,211	$ 410,211
Asset-Backed Notes | Oportun Issuance Trust (Series 2022-A) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	415,155	414,293
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-C)
Debt Instrument [Line Items]
Original Balance	500,000	500,000
Current balance	$ 448,152	$ 435,951
Weighted average interest rate	2.48%	2.48%
Original revolving period	3 years	3 years
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-C) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 512,762	$ 512,762
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-C) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	519,859	518,929
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-B)
Debt Instrument [Line Items]
Original Balance	500,000	500,000
Current balance	$ 452,363	$ 432,123
Weighted average interest rate	2.05%	2.05%
Original revolving period	3 years	3 years
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-B) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 512,759	$ 512,759
Asset-Backed Notes | Oportun Issuance Trust (Series 2021-B) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	519,228	519,182
Asset-Backed Notes | Oportun Funding XIV, LLC (Series 2021-A)
Debt Instrument [Line Items]
Original Balance	375,000	375,000
Current balance	$ 291,499	$ 348,046
Weighted average interest rate	1.79%	1.79%
Original revolving period	2 years	2 years
Asset-Backed Notes | Oportun Funding XIV, LLC (Series 2021-A) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 383,632	$ 383,632
Asset-Backed Notes | Oportun Funding XIV, LLC (Series 2021-A) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	318,191	389,740
Asset-Backed Notes | Oportun Funding XIII, LLC (Series 2019-A)
Debt Instrument [Line Items]
Original Balance	279,412	279,412
Current balance	$ 114,079	$ 192,334
Weighted average interest rate	3.46%	3.46%
Original revolving period	3 years	3 years
Asset-Backed Notes | Oportun Funding XIII, LLC (Series 2019-A) | Initial Collateral
Debt Instrument [Line Items]
Collateral balance	$ 294,118	$ 294,118
Asset-Backed Notes | Oportun Funding XIII, LLC (Series 2019-A) | Current Collateral
Debt Instrument [Line Items]
Collateral balance	$ 132,600	$ 218,571