Secured Debt, Net - Schedule of Secured Credit Facilities (Detail) - Secured credit facilities - Line of Credit $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($) lender loan	Dec. 31, 2022 USD ($)
Schedule Of Secured Credit Facilities [Line Items]
Lenders | lender	15
Borrowings	$ 12,809,913	$ 13,549,748
Loan Count | loan	171
Collateral	$ 18,613,231	$ 19,694,790
Recourse Limitation Wtd. Avg. (percentage)	34.00%
Others
Schedule Of Secured Credit Facilities [Line Items]
Lenders | lender	4
Borrowings	$ 1,558,353
Loan Count | loan	7
Collateral	$ 1,967,503
Recourse Limitation Wtd. Avg. (percentage)	25.00%
Recourse Limitation Range (percentage)	25.00%
Minimum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	25.00%
Maximum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	100.00%
USD
Schedule Of Secured Credit Facilities [Line Items]
Lenders | lender	14
Borrowings	$ 6,876,591
Loan Count | loan	131
Collateral	$ 10,791,188
Recourse Limitation Wtd. Avg. (percentage)	36.00%
USD | Minimum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	25.00%
USD | Maximum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	100.00%
GBP
Schedule Of Secured Credit Facilities [Line Items]
Lenders | lender	7
Borrowings	$ 2,391,449
Loan Count | loan	22
Collateral	$ 3,193,290
Recourse Limitation Wtd. Avg. (percentage)	27.00%
GBP | Minimum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	25.00%
GBP | Maximum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	50.00%
EUR
Schedule Of Secured Credit Facilities [Line Items]
Lenders | lender	7
Borrowings	$ 1,983,520
Loan Count | loan	11
Collateral	$ 2,661,250
Recourse Limitation Wtd. Avg. (percentage)	41.00%
EUR | Minimum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	25.00%
EUR | Maximum
Schedule Of Secured Credit Facilities [Line Items]
Recourse Limitation Range (percentage)	100.00%