Marketplace Revenue - Components of Marketplace Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Gain on sales of loans	$ 23,554	$ 21,907	$ 76,983	$ 49,547
Net fair value adjustments	(619)	2,705	24,277	(6,714)
Total marketplace revenue	173,837	174,556	560,187	408,018
Origination fees
Disaggregation of Revenue [Line Items]
Revenue	127,142	129,125	398,487	298,486
Servicing fees
Disaggregation of Revenue [Line Items]
Revenue	$ 23,760	$ 20,819	$ 60,440	$ 66,699