Fair Value of Financial Instruments - Schedule of Unobservable Inputs (Details) $ in Thousands	Jun. 30, 2024 USD ($) investment		Dec. 31, 2023 USD ($) investment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	$ 3,558,020	[1]	$ 756,145	[2]
Number of investments | investment	1		1
Senior Secured First Lien Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	$ 2,687,402		$ 632,343
Senior Secured Second Lien Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	157,304		52,126
Subordinated Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	144,149		35,500
Collateralized Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	11,899
Equity/Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	252,332		36,176
FBLC Senior Loan Fund, LLC
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	304,934
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	3,487,602		726,533
Level 3 | Senior Secured First Lien Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	2,672,353		615,704
Level 3 | Senior Secured First Lien Debt | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	73,316
Level 3 | Senior Secured First Lien Debt | Unobservable Inputs Not Developed
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	115,573		15,649
Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	2,456,128		597,286
Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value			2,769
Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	27,336
Level 3 | Senior Secured Second Lien Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	119,999		39,153
Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	116,535		39,153
Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	2,855
Level 3 | Senior Secured Second Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	609
Level 3 | Subordinated Debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	144,149		35,500
Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	49
Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	144,100		35,500
Level 3 | Collateralized Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	11,899
Level 3 | Collateralized Securities | Discount Rate | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	7,919
Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	3,980
Level 3 | Equity/Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	234,268		36,176
Level 3 | Equity/Other | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	2,233		117
Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	32,394		3,459
Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	932
Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	196,541		$ 32,600
Level 3 | Equity/Other | Discount Rate | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	553
Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	1,615
Level 3 | FBLC Senior Loan Fund, LLC
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	304,934
Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments at Fair Value	$ 304,934
Minimum | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	2.5		8.81
Minimum | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	5.4		6
Minimum | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.15
Minimum | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	10.12		13.35
Minimum | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	4.9
Minimum | Level 3 | Senior Secured Second Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.4
Minimum | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	10.17
Minimum | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.34		1.75
Minimum | Level 3 | Collateralized Securities | Discount Rate | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0
Minimum | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	2.52
Minimum | Level 3 | Equity/Other | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	50.73		13.5
Minimum | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	3		11.87
Minimum | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.22
Minimum | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.34		1.75
Minimum | Level 3 | Equity/Other | Discount Rate | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	13
Minimum | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.9
Minimum | Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	14.58
Maximum | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	90.01		25.58
Maximum | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	16.55		6
Maximum | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.39
Maximum | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	21.68		20.5
Maximum | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	4.9
Maximum | Level 3 | Senior Secured Second Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.4
Maximum | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	10.17
Maximum | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.58		1.75
Maximum | Level 3 | Collateralized Securities | Discount Rate | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	15.13
Maximum | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	3.61
Maximum | Level 3 | Equity/Other | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	50.73		13.5
Maximum | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	27.45		24.5
Maximum | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1
Maximum | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.58		1.75
Maximum | Level 3 | Equity/Other | Discount Rate | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	13
Maximum | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.9
Maximum | Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	14.58
Weighted Average | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	11.74		11
Weighted Average | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	9.45		6
Weighted Average | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.04
Weighted Average | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	14.24		14.95
Weighted Average | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	4.9
Weighted Average | Level 3 | Senior Secured Second Lien Debt | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.4
Weighted Average | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	10.17
Weighted Average | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.49		1.75
Weighted Average | Level 3 | Collateralized Securities | Discount Rate | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	8.28
Weighted Average | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	3.4
Weighted Average | Level 3 | Equity/Other | Market Yield | Yield Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	50.73		13.5
Weighted Average | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	13.01		18.14
Weighted Average | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.98
Weighted Average | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.48		1.75
Weighted Average | Level 3 | Equity/Other | Discount Rate | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	13
Weighted Average | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.9
Weighted Average | Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	14.58

[1] Percentages are based on net assets attributable to common stock as of June 30, 2024.

[2] Percentages are based on net assets attributable to common stock as of December 31, 2023.