Fair Value Measurements - Narrative (Details) $ in Thousands	Jun. 30, 2023 USD ($) loan	Dec. 31, 2022 USD ($) loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment, at fair value	$ 11,929,537	$ 11,359,236
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment, at fair value	11,929,537	11,359,236
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 internally developed price, assets	$ 1,000	$ 3,000
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 | loan	6	14
Excess of third party prices over internally developed price, assets	$ 16,000	$ 14,000
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 internally developed price, assets	$ 48,000	$ 122,000
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 | loan	2	6
Assets, fair value disclosure	$ 8,000	$ 35,000
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	$ 61,000	$ 96,000
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	4	8
Assets, fair value disclosure	$ 644,000	$ 2,100,000
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 internally developed price, assets	7,000	32,000
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	45,000	82,000
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 internally developed price, assets	$ 596,000	$ 2,000,000