Loans Held for Investment - Loan Products Type and Characteristics (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Unpaid Principal Balance	$ 12,570,243	$ 12,060,530
Residential Portfolio Segment
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 1,872,172	$ 2,063,171
% of Unpaid Principal Balance	14.80%	17.10%
Residential Portfolio Segment | Bankruptcy
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 168,162	$ 211,226
% of Unpaid Principal Balance	1.30%	1.80%
Residential Portfolio Segment | Foreclosure
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 334,893	$ 391,958
% of Unpaid Principal Balance	2.70%	3.20%
Residential Portfolio Segment | REO
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 29,358	$ 33,843
% of Unpaid Principal Balance	0.20%	0.30%
Residential Portfolio Segment | 30 Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 731,633	$ 778,196
% of Unpaid Principal Balance	5.80%	6.50%
Residential Portfolio Segment | 60 Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 219,106	$ 248,579
% of Unpaid Principal Balance	1.70%	2.10%
Residential Portfolio Segment | 90+ Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 389,020	$ 399,369
% of Unpaid Principal Balance	3.10%	3.30%