Financing Agreements - Borrowings Under Repurchase Agreement (Details) - Repurchase Agreement Borrowings - Held at Fair Value - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 3,612,829	$ 3,578,816
Weighted Average Interest Rate	7.30%	7.36%
Within 30 days
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 3,612,829	$ 3,578,816
Weighted Average Interest Rate	7.30%	7.36%
Over 30 days to 3 months
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 0	$ 0
Weighted Average Interest Rate	0.00%	0.00%
Over 3 months to 12 months
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 0	$ 0
Weighted Average Interest Rate	0.00%	0.00%
Over 12 months
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 0	$ 0
Weighted Average Interest Rate	0.00%	0.00%