v3.26.1
Fair Value of Financial Instruments - Schedule of Unobservable Inputs (Details)
$ in Thousands
Mar. 31, 2026
USD ($)
investment
Dec. 31, 2025
USD ($)
investment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value $ 4,050,457 [1],[2],[3] $ 4,071,008 [4],[5],[6]
Number of investments | investment 1 1
Senior Secured First Lien Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value $ 3,066,779 $ 3,136,374
Senior Secured Second Lien Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 165,459 152,406
Subordinated Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 285,017 259,132
Collateralized Securities    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 4,098 4,861
Equity/Other    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 306,398 293,279
FBLC Senior Loan Fund, LLC    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 222,706 224,956
Level 3    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 3,954,010 3,998,057
Level 3 | Senior Secured First Lien Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 3,051,735 3,121,003
Level 3 | Senior Secured First Lien Debt | Unobservable Inputs Not Developed    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 51,744 96,537
Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 2,809,642 2,970,031
Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 166,113 32,285
Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 24,236 22,150
Level 3 | Senior Secured Second Lien Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 101,855 110,594
Level 3 | Senior Secured Second Lien Debt | Unobservable Inputs Not Developed    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 51,433 16,600
Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 12,934 55,631
Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 37,488 37,695
Level 3 | Senior Secured Second Lien Debt | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value   668
Level 3 | Subordinated Debt    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 285,017 259,132
Level 3 | Subordinated Debt | Unobservable Inputs Not Developed    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 4,548  
Level 3 | Subordinated Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 38,945 41,466
Level 3 | Subordinated Debt | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 47,542 33,911
Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 9,882 9,654
Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 184,100 174,101
Level 3 | Collateralized Securities    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 4,098 4,861
Level 3 | Collateralized Securities | Discount Margin | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 3,553 4,322
Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 545 539
Level 3 | Equity/Other    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 288,599 277,511
Level 3 | Equity/Other | Unobservable Inputs Not Developed    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 0 0
Level 3 | Equity/Other | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 20,874 20,310
Level 3 | Equity/Other | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 12,473 10,330
Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 26,507 26,748
Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 12,529 12,528
Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 212,249 205,980
Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 3,967 1,615
Level 3 | FBLC Senior Loan Fund, LLC    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Investments at Fair Value 222,706 224,956
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 $ 222,706 $ 224,956
Minimum | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0000 0.0000
Minimum | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 5.75 3.83
Minimum | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.19 0.19
Minimum | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1718 0.1140
Minimum | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 6.54 6.86
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 | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1583 0.1427
Minimum | Level 3 | Subordinated Debt | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Minimum | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 9.10 0.0983
Minimum | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.15 1.15
Minimum | Level 3 | Collateralized Securities | Discount Margin | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0000 0.0000
Minimum | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.23 0.2
Minimum | Level 3 | Equity/Other | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0100 11.59
Minimum | Level 3 | Equity/Other | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Minimum | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 2.25 2.58
Minimum | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.19 0.0019
Minimum | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.15 1.15
Minimum | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 4.47 3.92
Minimum | Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1176 0.1122
Maximum | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.2500 0.3369
Maximum | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 15.10 15.57
Maximum | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.90 0.62
Maximum | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1955 0.2450
Maximum | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 15.10 15.57
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 | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1583 0.1427
Maximum | Level 3 | Subordinated Debt | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Maximum | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 10.25 0.105
Maximum | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.53 1.56
Maximum | Level 3 | Collateralized Securities | Discount Margin | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1670 0.1690
Maximum | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.52 0.49
Maximum | Level 3 | Equity/Other | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1162 21.8
Maximum | Level 3 | Equity/Other | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Maximum | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 25.00 25.5
Maximum | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.90 0.012
Maximum | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.53 1.56
Maximum | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 4.47 3.92
Maximum | Level 3 | FBLC Senior Loan Fund, LLC | Discount Rate | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1176 0.1122
Weighted Average | Level 3 | Senior Secured First Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0976 0.1025
Weighted Average | Level 3 | Senior Secured First Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 8.88 8.44
Weighted Average | Level 3 | Senior Secured First Lien Debt | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.29 0.3
Weighted Average | Level 3 | Senior Secured Second Lien Debt | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1768 0.1326
Weighted Average | Level 3 | Senior Secured Second Lien Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 10.40 10.43
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 | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1583 0.1427
Weighted Average | Level 3 | Subordinated Debt | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Weighted Average | Level 3 | Subordinated Debt | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 9.10 0.0983
Weighted Average | Level 3 | Subordinated Debt | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.36 1.38
Weighted Average | Level 3 | Collateralized Securities | Discount Margin | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1670 0.1690
Weighted Average | Level 3 | Collateralized Securities | Asset Recovery | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.48 0.46
Weighted Average | Level 3 | Equity/Other | Market Yield | Yield Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0611 16.75
Weighted Average | Level 3 | Equity/Other | Market Yield | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.1078 10.25
Weighted Average | Level 3 | Equity/Other | EBITDA Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 12.34 12.51
Weighted Average | Level 3 | Equity/Other | Revenue Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.30 0.0065
Weighted Average | Level 3 | Equity/Other | Tangible Net Asset Value Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 1.38 1.41
Weighted Average | Level 3 | Equity/Other | Adjusted BV Multiple | Waterfall Analysis    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 4.47 3.92
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 0.1176 0.1122
[1] Percentages are based on net assets attributable to common stock as of March 31, 2026.
[2] Unless otherwise indicated, all investments in the consolidated schedules of investments are non-affiliated, non-controlled investments.
[3] Unless otherwise indicated, all of the Company's investments or a portion thereof are pledged as collateral under the JPM Revolver Facility.
[4] Percentages are based on net assets attributable to common stock as of December 31, 2025.
[5] Unless otherwise indicated, all investments in the consolidated schedules of investments are non-affiliated, non-controlled investments.
[6] Unless otherwise indicated, all of the Company's investments or a portion thereof are pledged as collateral under the JPM Revolver Facility (as defined below).