Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021 USD ($) loan director
Commitments And Contingencies [Line Items]
Number of loans receivable | loan	118
Number Of directors eligible for annual compensation | director	6
Total loans receivable
Commitments And Contingencies [Line Items]
Unfunded loan commitments	$ 4,200,000,000
Aggregate unfunded loan commitments	2,500,000,000
Unfunded Commitments Related To Loans Receivable Excluding Identified Financing	$ 1,700,000,000
Weighted-average future funding period	3 years 7 months 6 days
Five Independent Board of Directors
Commitments And Contingencies [Line Items]
Annual cash compensation	$ 210,000
Annual cash compensation paid in cash	95,000
Annual cash compensation paid in the form of deferred stock units	115,000
Chairperson of Audit Committee
Commitments And Contingencies [Line Items]
Annual cash compensation	20,000
Compensation and Corporate Governance Committees
Commitments And Contingencies [Line Items]
Annual cash compensation	10,000
Compensation and Corporate Governance Committees | Amendment One
Commitments And Contingencies [Line Items]
Annual cash compensation	15,000
Audit Committee Members
Commitments And Contingencies [Line Items]
Annual cash compensation	10,000
Investment risk management committee
Commitments And Contingencies [Line Items]
Annual cash compensation	$ 7,500