Fair Value - Key Inputs Used in Determining Fair Value of IO (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 4,182,382	$ 4,836,292
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	7.40%	6.50%
Fair value inputs, Prepayment speed	5.40%	5.50%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	18.80%	17.90%
Fair value inputs, Prepayment speed	8.10%	8.50%
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	5.40%	5.50%
Fair value inputs, Prepayment speed	7.50%	7.00%
IO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 81,256	$ 94,231
IO [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	5.90%	5.10%
Fair value inputs, Prepayment speed	11.70%	10.90%
Fair value inputs, Equivalent life (in years)	4 years 4 months 24 days	4 years 8 months 12 days
IO [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	6.50%	5.10%
Fair value inputs, Prepayment speed	12.10%	11.00%
Fair value inputs, Equivalent life (in years)	6 years 9 months 18 days	7 years 2 months 12 days
IO [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	6.50%	5.10%
Fair value inputs, Prepayment speed	11.70%	10.90%
Fair value inputs, Equivalent life (in years)	6 years 8 months 12 days	7 years 1 month 6 days