Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	Jun. 30, 2023 USD ($) loan	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Joint venture capital contribution percentage							85.00%
Restricted cash	$ 0		$ 0
Borrower escrows	505,900		459,600
CECL reserve	363,875	$ 336,591	326,137	$ 133,024	$ 122,221	$ 124,679
Principal balance	$ 24,482,749		$ 25,017,880
Level 3 | Measurement Input, Cap Rate | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Measurement input (percentage)	0.0525
Level 3 | Measurement Input, Cap Rate | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Measurement input (percentage)	0.0775
Level 3 | Measurement Input, Discount Rate | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Measurement input (percentage)	0.0728
Level 3 | Measurement Input, Discount Rate | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Measurement input (percentage)	0.0975
Level 3 | Fair Value, Nonrecurring
Accounts, Notes, Loans and Financing Receivable [Line Items]
CECL reserve	$ 214,400
Number of loans accounted for under cost-recovery method, floating rate | loan	7
Principal balance	$ 1,100,000
Walker and Dunlop
Accounts, Notes, Loans and Financing Receivable [Line Items]
Joint venture capital contribution percentage							15.00%