Fair Value - Key Inputs Used in Determining Fair Value of IO (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 4,305,991	$ 4,452,859
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Prepayment speed	5.90%	7.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Prepayment speed	24.40%	21.50%
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, Pricing spread	6.10%	8.40%
IO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 75,264	$ 72,502
IO [Member] \| Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Option-Adjusted Spread	3.10%	4.70%
Fair value inputs, Prepayment speed	8.20%	11.00%
Fair value inputs, Equivalent life (in years)	4 years 2 months 12 days	4 years
IO [Member] \| Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Option-Adjusted Spread	3.50%	4.70%
Fair value inputs, Prepayment speed	10.40%	13.60%
Fair value inputs, Equivalent life (in years)	8 years 10 months 24 days	7 years 8 months 12 days
IO [Member] \| Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Option-Adjusted Spread	3.10%	4.70%
Fair value inputs, Prepayment speed	8.20%	11.00%
Fair value inputs, Equivalent life (in years)	8 years 9 months 18 days	7 years 7 months 6 days