Mortgage Loans on Real Estate - Loans (UPB) Collateralized by Real Estate - Additional Informaiton (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Aggregate Cost of Mortgage loans, Federal Income tax	$ 4,156,554	$ 3,553,379
Interest Expense, Debt	$ 188,500	$ 168,400
Residential Real Estate
Debt Instrument [Line Items]
Provision for prepayment penalty rate	3.00%
Commercial Real Estate
Debt Instrument [Line Items]
Provision for prepayment penalty rate	5.00%