Fair Values - Schedule of Details of Book Value, Face Amount, and Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financial assets
Cash and cash equivalents	$ 421,495	$ 291,340
Loans receivable, net	23,849,497	25,160,343
Financial liabilities
Securitized debt obligations, net	2,509,254	2,664,010
Securitized debt obligations, net, Face Amount	2,512,511	2,673,541
Asset-specific debt net, Face Amount	935,435	950,278
Loan participations sold, net	275,184	224,232
Loan participations sold, net, Face Amount	275,697	224,744
Secured debt, net
Financial liabilities
Debt, Face Amount	12,809,913	13,549,748
Secured term loans, net
Financial liabilities
Debt, Face Amount	2,140,720	2,157,218
Senior secured notes, net
Financial liabilities
Debt, Face Amount	366,590	400,000
Convertible notes, net
Financial liabilities
Debt, Face Amount	300,000	520,000
Book Value
Financial assets
Cash and cash equivalents	421,495	291,340
Loans receivable, net	23,252,478	24,691,743
Financial liabilities
Securitized debt obligations, net	2,509,254	2,664,010
Asset-specific debt, net	930,757	942,503
Loan participations sold, net	275,184	224,232
Book Value \| Secured debt, net
Financial liabilities
Debt	12,793,344	13,528,164
Book Value \| Secured term loans, net
Financial liabilities
Debt	2,104,824	2,114,549
Book Value \| Senior secured notes, net
Financial liabilities
Debt	362,981	395,166
Book Value \| Convertible notes, net
Financial liabilities
Debt	295,527	514,257
Fair Value
Financial assets
Cash and cash equivalents	421,495	291,340
Loans receivable, net	23,007,371	24,445,042
Financial liabilities
Securitized debt obligations, net	2,309,845	2,597,377
Asset-specific debt, net	924,278	934,815
Loan participations sold, net	269,646	217,717
Fair Value \| Secured debt, net
Financial liabilities
Debt	12,466,689	13,121,306
Fair Value \| Secured term loans, net
Financial liabilities
Debt	2,097,253	2,103,943
Fair Value \| Senior secured notes, net
Financial liabilities
Debt	308,784	343,665
Fair Value \| Convertible notes, net
Financial liabilities
Debt	$ 267,468	$ 478,232

Asset-specific debt, Gross.

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Asset-specific debt, net.

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Participating Mortgage Loans, Participation Liabilities, Principal Amount

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Securitized debt obligations net.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Face (par) amount of debt instrument at time of issuance.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The aggregate amount of the participation liability at the end of the accounting period.

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