Securitizations and Variable Interest Entities - Summary of Financial Asset and Liability Involvement with Consolidated VIEs (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Assets	$ 4,750,760	$ 1,863,293
Liabilities	(3,945,970)	(1,139,122)
Consolidated VIEs
Variable Interest Entity [Line Items]
Assets	113,069	218,165
Liabilities	(104,924)	(206,157)
Net Assets	8,145	12,008
LC Trust | Consolidated VIEs
Variable Interest Entity [Line Items]
Assets	17,953	55,447
Liabilities	(15,505)	(53,068)
Net Assets	2,448	2,379
Consolidated trusts | Consolidated VIEs
Variable Interest Entity [Line Items]
Assets	95,116	162,460
Liabilities	(89,419)	(153,089)
Net Assets	$ 5,697	9,371
Warehouse credit facility | Consolidated VIEs
Variable Interest Entity [Line Items]
Assets		258
Liabilities		0
Net Assets		$ 258