Loans Receivable, Net - Net Book Value, Total Loan Exposure and Net Loan Exposure of Loans Receivable Based on Internal Risk Ratings (Detail) $ in Thousands	Jun. 30, 2023 USD ($) security_loan	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) security_loan	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	191		203
Net Book Value	$ 24,482,749		$ 25,017,880
CECL reserve	(363,875)	$ (336,591)	(326,137)	$ (133,024)	$ (122,221)	$ (124,679)
Loans receivable, net	24,118,874		24,691,743
Total Loan Exposure	25,755,473		26,810,281
Net Loan Exposure	23,115,138		23,659,183
Total loan exposure including non-consolidated senior interests	1,200,000		1,600,000
Net loan exposure, asset-specific debt	875,600		950,300
Net loan exposure, loan participations sold	$ 236,300		$ 224,700
1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	14		17
Net Book Value	$ 1,079,927		$ 1,403,185
Total Loan Exposure	1,129,034		1,428,232
Net Loan Exposure	$ 1,080,883		$ 1,170,725
2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	40		36
Net Book Value	$ 6,119,929		$ 5,880,424
Total Loan Exposure	6,702,386		6,562,852
Net Loan Exposure	$ 5,162,941		$ 5,292,933
3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	115		134
Net Book Value	$ 13,058,671		$ 14,128,133
Total Loan Exposure	13,694,483		15,209,018
Net Loan Exposure	$ 12,914,436		$ 13,826,730
4
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	15		11
Net Book Value	$ 3,138,665		$ 2,677,027
Total Loan Exposure	3,143,646		2,680,145
Net Loan Exposure	$ 3,085,355		$ 2,628,539
5
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | security_loan	7		5
Net Book Value	$ 1,085,557		$ 929,111
Total Loan Exposure	1,085,924		930,034
Net Loan Exposure	$ 871,523		$ 740,256