Fair Value - Principal Amount, Carrying Value and Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financial assets:
Unpaid Principal Balance	$ 3,225,635	$ 3,586,248
Financial liabilities:
Principal amount, financial liabilities	2,858,915	3,169,278
Commercial mortgage
Financial assets:
Unpaid Principal Balance	3,225,635	3,586,248
Financial liabilities:
Future funding commitments	225,600	263,400
Carrying Value
Financial assets:
Loans held for investment, net	3,112,973	3,468,472
Fair Value
Financial assets:
Loans held for investment, net	3,118,907	3,480,001
Securitization bonds payable, net
Financial liabilities:
Principal amount, financial liabilities	995,187	1,172,717
Securitization bonds payable, net | Carrying Value
Financial liabilities:
Financial liabilities	992,583	1,167,600
Securitization bonds payable, net | Fair Value
Financial liabilities:
Financial liabilities	995,187	1,172,717
Mortgage and other notes payable, net
Financial liabilities:
Principal amount, financial liabilities	646,477	656,568
Mortgage and other notes payable, net | Carrying Value
Financial liabilities:
Financial liabilities	644,891	656,468
Mortgage and other notes payable, net | Fair Value
Financial liabilities:
Financial liabilities	620,611	656,568
Master repurchase facilities
Financial liabilities:
Principal amount, financial liabilities	1,217,251	1,339,993
Master repurchase facilities | Carrying Value
Financial liabilities:
Financial liabilities	1,217,251	1,339,993
Master repurchase facilities | Fair Value
Financial liabilities:
Financial liabilities	$ 1,217,251	$ 1,339,993