Related Party Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended			6 Months Ended
	Aug. 06, 2024	May 05, 2020	Jan. 01, 2020	Sep. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Maximum percentage of interest on amounts due from affiliates (percent)							7.02%
Tax receivable agreement termination, cash payments per partnership unit exchanged (in dollars per share)			$ 1.50
Tax receivable agreement termination, term of annual installments			5 years
Tax receivable agreement termination, annual cash payments per partnership unit exchanged (in dollars per share)			$ 0.30
Conversion of units, deferred consideration obligation, discount			$ 11.3
Percentage of estimated realizable tax benefit to be paid by corporate taxpayers on exchange transactions							85.00%
Interest and other income					$ 52.1	$ 50.2	$ 109.7	$ 94.2
Fair value of assets					9,136.5		9,136.5
Net change in unrealized loss					(23.6)	(17.6)	(127.5)	(180.0)
Carlyle Secured Lending, Inc. Merger | Subsequent event
Related Party Transaction [Line Items]
Issuance of common stock (in shares)	2,000,000
Share price (in dollars per share)	$ 8.98
Forecast | Carlyle Secured Lending, Inc. Merger
Related Party Transaction [Line Items]
Net change in unrealized loss				$ 45.0
Level III
Related Party Transaction [Line Items]
Fair value of assets					8,536.7		8,536.7		$ 7,379.4
Level III | BDC preferred shares
Related Party Transaction [Line Items]
Fair value of assets									81.7
Affiliated Entity
Related Party Transaction [Line Items]
Notes receivable and accrued interest from affiliates					$ 22.2		$ 22.2		$ 25.0
Accrued interest percentage					1.00%		1.00%
Floor rate					3.50%		3.50%
Actual rate					0.0750		0.0750
Related Party | Carlyle Secured Lending, Inc.
Related Party Transaction [Line Items]
Purchase of investment (in shares)		2,000,000
Purchase of investment (in dollars per share)		$ 25
Dividend rate, percentage		7.00%
Dividend rate, payable in shares, percentage		9.00%
Initial conversion price (in usd per share)		$ 9.50
Interest and other income					$ 0.9	$ 0.9	$ 1.8	$ 1.8