Use of Special Purpose Entities and Variable Interest Entities (Loan Securitization Transaction) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Weighted Average Cost of Funding	3.46%	2.58%
Asset-backed Securities, Securitized Loans and Receivables
Variable Interest Entity [Line Items]
Aggregate unpaid principal balance of residential whole loans sold	$ 6,732,609	$ 3,984,355
Outstanding amount of Senior Bonds, at carrying value	922,220	1,334,342
Outstanding amount of Senior Bonds, at fair value	2,435,370	1,316,131
Outstanding amount of Senior Bonds, total	$ 3,357,590	$ 2,650,473
Weighted Average Cost of Funding	3.38%	2.01%
Weighted average contractual maturity of Senior Bonds	38 years	36 years
Cash received	$ 5,300,681	$ 3,682,082
Debt issuance cost	2,900	6,800
Senior Notes
Variable Interest Entity [Line Items]
Cash received	2,300,000	2,400,000
Senior Notes | Asset-backed Securities, Securitized Loans and Receivables
Variable Interest Entity [Line Items]
Debt instrument, face amount	5,333,090	3,667,790
Proceeds from Senior bond sold with Step up feature	$ 1,900,000	329,000
Senior Notes | Asset-backed Securities, Securitized Loans and Receivables | Minimum
Variable Interest Entity [Line Items]
Debt instrument, basis spread on variable rate	1.00%
Debt instrument, coupon step-up period	30 months
Senior Notes | Asset-backed Securities, Securitized Loans and Receivables | Maximum
Variable Interest Entity [Line Items]
Debt instrument, basis spread on variable rate	3.00%
Debt instrument, coupon step-up period	48 months
Senior Notes | Asset-backed Securities, Securitized Loans and Receivables | Median
Variable Interest Entity [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Senior Support Certificates | Asset-backed Securities, Securitized Loans and Receivables
Variable Interest Entity [Line Items]
Debt instrument, face amount	$ 715,640	$ 283,930