Fair Value - Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financial assets not carried at fair value:
Loans held-for-investment	$ 17,574,249	$ 18,401,439
HTM debt securities	619,397	676,652
Carrying Value
Financial assets not carried at fair value:
Loans held-for-investment	17,574,249	18,401,439
HTM debt securities	606,254	673,470
Financial liabilities not carried at fair value:
Secured financing agreements, CLOs and SASB	17,552,979	18,177,756
Unsecured senior notes	2,158,888	2,329,211
Fair Value
Financial assets not carried at fair value:
Loans held-for-investment	17,483,058	18,215,072
HTM debt securities	581,160	637,275
Financial liabilities not carried at fair value:
Secured financing agreements, CLOs and SASB	17,466,172	18,017,651
Unsecured senior notes	$ 2,128,835	$ 2,199,135