Investment Portfolio Financing - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Principal balance	$ 3,705,887	$ 4,179,211
Collateralized loan obligations
Debt Instrument [Line Items]
Principal balance	2,142,939	2,461,170
Secured credit agreements
Debt Instrument [Line Items]
Principal balance	1,039,185	1,108,386
Asset-specific financing arrangements
Debt Instrument [Line Items]
Principal balance	492,563	565,376
Secured revolving credit facility
Debt Instrument [Line Items]
Principal balance	0	44,279
Mortgage loan payable
Debt Instrument [Line Items]
Principal balance	$ 31,200	$ 0