Fair Value Measurements - Narrative (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2025 USD ($) investment loan	Dec. 31, 2024 USD ($) investment loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment, at fair value	$ 10,983,840,000	$ 11,196,678,000
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment, at fair value	10,983,840,000	11,196,678,000
Investments with Difference Between Model Price and Third-Party Price | Securitized debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess of third party prices over (under) internally developed price, assets	$ 303,000	$ 355,000
Investments with Difference Between Model Price and Third-Party Price | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans internally valued lower than third party prices | investment	3	6
Excess of third party prices over (under) internally developed price, assets	$ 3,000,000	$ 6,000,000
Investments with Difference Between Model Price and Third-Party Price | Securitized Loans Held For Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess of third party prices over (under) internally developed price, assets	$ 17,000,000	$ 28,000,000
Internal Assessment | Investments with Difference Between Model Price and Third-Party Price | Securitized debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans internally valued lower than third party prices | investment	1	2
Assets, fair value disclosure	$ 3,000,000	$ 3,200,000
Internal Assessment | Investments with Difference Between Model Price and Third-Party Price | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	$ 15,000,000	$ 37,000,000
Internal Assessment | Investments with Difference Between Model Price and Third-Party Price | Securitized Loans Held For Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans internally valued lower than third party prices | loan	1	4
Assets, fair value disclosure	$ 211,000,000	$ 440,000,000
Third Party Assessment | Investments with Difference Between Model Price and Third-Party Price | Securitized debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess of third party prices over (under) internally developed price, assets	2,700,000	2,900,000
Third Party Assessment | Investments with Difference Between Model Price and Third-Party Price | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	12,000,000	31,000,000
Third Party Assessment | Investments with Difference Between Model Price and Third-Party Price | Securitized Loans Held For Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess of third party prices over (under) internally developed price, assets	$ 194,000,000	$ 412,000,000