Loans Held for Investment - Loan Products Type and Characteristics (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Unpaid Principal Balance	$ 11,639,449	$ 11,876,358
Residential Portfolio Segment
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 1,859,250	$ 1,893,900
% of Unpaid Principal Balance	15.90%	15.80%
Residential Portfolio Segment | Bankruptcy
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 180,222	$ 181,410
% of Unpaid Principal Balance	1.50%	1.50%
Residential Portfolio Segment | Foreclosure
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 334,727	$ 346,396
% of Unpaid Principal Balance	2.90%	2.90%
Residential Portfolio Segment | REO
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 30,841	$ 29,416
% of Unpaid Principal Balance	0.30%	0.20%
Residential Portfolio Segment | 30 Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 746,284	$ 763,581
% of Unpaid Principal Balance	6.40%	6.40%
Residential Portfolio Segment | 60 Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 236,542	$ 235,169
% of Unpaid Principal Balance	2.00%	2.00%
Residential Portfolio Segment | 90+ Days Delinquent
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Outstanding balance past due	$ 330,634	$ 337,928
% of Unpaid Principal Balance	2.80%	2.80%