Borrowings - Secured Financing (Details) - USD ($)	1 Months Ended
	Aug. 31, 2020	Feb. 29, 2020	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total Issued					$ 1,343,000,000		$ 1,110,000,000
Total loans and accrued interest amount securitized at inception					$ 1,463,230,000		$ 1,208,963,000
Issuance 2019-A
Debt Instrument [Line Items]
Total Issued			$ 453,000,000
Weighted Average Life (in years)				4 years 3 months 3 days
Basis spread on variable rate				0.92%
Issuance 2019-B
Debt Instrument [Line Items]
Total Issued						$ 657,000,000
Weighted Average Life (in years)			4 years 4 months 28 days
Basis spread on variable rate			1.01%
Issuance 2020-A
Debt Instrument [Line Items]
Total Issued		$ 636,000,000
Weighted Average Life (in years)		4 years 2 months 4 days
Basis spread on variable rate		0.88%
Issuance 2020-B
Debt Instrument [Line Items]
Total Issued	$ 707,000,000
Weighted Average Life (in years)	4 years 1 month 20 days
Basis spread on variable rate	1.30%