Fair Value Measurements - Summary of Fair Value of Financial Assets and Liabilities (Details) - Fair Value Measurements Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Carrying Value | Loans Held for Investment
Financial assets
Financial assets, nonrecurring	$ 5,069,481	$ 4,867,203
Carrying Value | Collateralized Loan Obligation
Financial liabilities
Financial liabilities, nonrecurring	2,810,626	2,545,691
Carrying Value | Secured Credit Agreements
Financial liabilities
Financial liabilities, nonrecurring	1,162,576	1,162,206
Carrying Value | Secured Revolving Credit Facility
Financial liabilities
Financial liabilities, nonrecurring	30,380
Estimate of Fair Value Measurement | Level III | Loans Held for Investment
Financial assets
Financial assets, nonrecurring	5,091,160	4,899,666
Estimate of Fair Value Measurement | Level III | Collateralized Loan Obligation
Financial liabilities
Financial liabilities, nonrecurring	2,828,618	2,558,544
Estimate of Fair Value Measurement | Level III | Secured Credit Agreements
Financial liabilities
Financial liabilities, nonrecurring	1,165,000	$ 1,169,710
Estimate of Fair Value Measurement | Level III | Secured Revolving Credit Facility
Financial liabilities
Financial liabilities, nonrecurring	$ 30,380