Consolidation - Narrative (Details)	1 Months Ended	9 Months Ended
	Sep. 30, 2023 USD ($) collateralized_loan_obligation	Sep. 30, 2023 USD ($) collateralized_loan_obligation	Dec. 31, 2022 USD ($)
Variable Interest Entity [Line Items]
Derivative liabilities	$ 0	$ 0
CLOs
Variable Interest Entity [Line Items]
Number of CLOs consolidated | collateralized_loan_obligation	8	8
Investments	$ 1,978,308,000	$ 1,978,308,000	$ 2,106,764,000
Nonconsolidated
Variable Interest Entity [Line Items]
Carrying value and maximum risk of loss	25,300,000	25,300,000
Subordinated Debt | CLOs
Variable Interest Entity [Line Items]
Payments to acquire investments	26,400,000
Senior Notes | CLOs
Variable Interest Entity [Line Items]
Unpaid principal balance exceeds fair value	107,000,000	107,000,000
Subordinated Notes - Newfleet CLO 2016-1 | CLOs
Variable Interest Entity [Line Items]
Debt par value	2,200,000,000	2,200,000,000
Subordinated Notes - Newfleet CLO 2016-1 | Subordinated Debt | CLOs
Variable Interest Entity [Line Items]
Debt par value	237,400,000	237,400,000
Senior Secured Floating Rate Notes - Newfleet CLO 2016-1 | Senior Notes | CLOs
Variable Interest Entity [Line Items]
Debt par value	$ 1,900,000,000	$ 1,900,000,000
Minimum | Senior Secured Floating Rate Notes - Newfleet CLO 2016-1 | LIBOR | CLOs
Variable Interest Entity [Line Items]
Basis spread on variable rate (as percent)		0.80%
Maximum | Senior Secured Floating Rate Notes - Newfleet CLO 2016-1 | LIBOR | CLOs
Variable Interest Entity [Line Items]
Basis spread on variable rate (as percent)		9.10%