Marketplace Revenue - Components of Marketplace Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Gain on sales of loans	$ 19,317	$ 1,724	$ 27,640		$ 15,985
Net fair value adjustments	(4,098)	(6,032)	(9,419)	[1]	(95,818)	[1]
Total marketplace revenue	151,735	18,881	233,462		121,358
Origination fees
Disaggregation of Revenue [Line Items]
Net Revenue	113,802	3,874	169,361		140,117
Servicing fees
Disaggregation of Revenue [Line Items]
Net Revenue	$ 22,714	$ 19,315	$ 45,880		$ 61,074

[1] Prior period amounts have been reclassified to conform to the current period presentation. See “Notes to Condensed Consolidated Financial Statements – Note 1. Summary of Significant Accounting Policies” for additional information.