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Fair Value - Principal Amount, Carrying Value and Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Financial assets:
Principal Amount	$ 3,089,431			$ 2,679,909
Financial liabilities:
Principal amount, financial liabilities	2,643,082			2,476,490
Current expected credit loss reserve	106,317	$ 98,658	$ 85,316	87,401	$ 126,905	$ 136,567	$ 155,365	$ 165,932
Commercial mortgage
Financial assets:
Principal Amount	3,089,431			2,679,909
Financial liabilities:
Future funding commitments	145,200			112,200
Securitization bonds payable, net
Financial liabilities:
Principal amount, financial liabilities	1,371,022			982,090
Mortgage and other notes payable, net
Financial liabilities:
Principal amount, financial liabilities	212,207			416,302
Credit facilities
Financial liabilities:
Principal amount, financial liabilities	1,059,853			1,078,098
Carrying Value
Financial assets:
Loans and preferred equity held for investment, net	3,082,324			2,678,315
Carrying Value \| Securitization bonds payable, net
Financial liabilities:
Financial liabilities	1,362,731			977,082
Carrying Value \| Mortgage and other notes payable, net
Financial liabilities:
Financial liabilities	210,988			414,060
Carrying Value \| Credit facilities
Financial liabilities:
Financial liabilities	1,059,853			1,078,098
Fair Value
Financial assets:
Loans and preferred equity held for investment, net	2,741,020			2,657,083
Fair Value \| Securitization bonds payable, net
Financial liabilities:
Financial liabilities	1,371,022			982,090
Fair Value \| Mortgage and other notes payable, net
Financial liabilities:
Financial liabilities	206,061			394,819
Fair Value \| Credit facilities
Financial liabilities:
Financial liabilities	$ 1,059,853			$ 1,078,098