v3.25.3
Fair Value - Summary of Changes in Fair Value of Level 3 Assets and Liabilities (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2025
Sep. 30, 2025
Dec. 31, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Opening balance $ 2,086,166 $ 1,956,286 $ 2,110,586
Net realized gain (loss) 1,344 1,721 (2,068)
Net change in unrealized gain (loss) $ 554 $ 1,759 $ 1,531
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net Change In Unrealized Gain Loss On Investments Net Change In Unrealized Gain Loss On Investments Net Change In Unrealized Gain Loss On Investments
Purchase of investment securities $ 280,589 [1] $ 814,330 [1] $ 479,716 [2]
Proceeds from dispositions of investment securities (311,936) (717,379) (633,479)
Transfers in/out of Level 3 0 0 0
Closing balance 2,056,717 2,056,717 1,956,286
Net change in unrealized gain (loss) $ 698 $ 4,724 $ 5,687
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net Change In Unrealized Gain Loss On Investments Net Change In Unrealized Gain Loss On Investments Net Change In Unrealized Gain Loss On Investments
Senior Secured Loans [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Opening balance $ 1,268,904 $ 1,117,118 $ 1,277,539
Net realized gain (loss) 1,360 1,755 (1,400)
Net change in unrealized gain (loss) (2,574) (4,098) (3,598)
Purchase of investment securities 272,045 [1] 791,182 [1] 411,598 [2]
Proceeds from dispositions of investment securities (288,499) (654,721) (567,021)
Transfers in/out of Level 3 0 0 0
Closing balance 1,251,236 1,251,236 1,117,118
Net change in unrealized gain (loss) (2,430) (1,133) 1,533
Equipment Financing [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Opening balance 138,988 181,016 256,819
Net realized gain (loss) (16) (34) 0
Net change in unrealized gain (loss) (1,844) (12,183) (12,646)
Purchase of investment securities 7,491 [1] 15,041 [1] 2,852 [2]
Proceeds from dispositions of investment securities (22,796) (62,017) (66,009)
Transfers in/out of Level 3 0 0 0
Closing balance 121,823 121,823 181,016
Net change in unrealized gain (loss) (1,844) (12,183) (12,646)
Preferred Equity [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Opening balance 32,510 31,682 3,801
Net realized gain (loss) 0 0 0
Net change in unrealized gain (loss) (519) (1,247) 49
Purchase of investment securities 806 [1] 2,362 [1] 27,832 [2]
Proceeds from dispositions of investment securities (641) (641) 0
Transfers in/out of Level 3 0 0 0
Closing balance 32,156 32,156 31,682
Net change in unrealized gain (loss) (519) (1,247) 49
Common Equity/Equity Interests/Warrants [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Opening balance 645,764 626,470 572,427
Net realized gain (loss) 0 0 (668)
Net change in unrealized gain (loss) 5,491 19,287 17,726
Purchase of investment securities 247 [1] 5,745 [1] 37,434 [2]
Proceeds from dispositions of investment securities 0 0 (449)
Transfers in/out of Level 3 0 0 0
Closing balance 651,502 651,502 626,470
Net change in unrealized gain (loss) $ 5,491 $ 19,287 $ 16,751
[1] Includes PIK capitalization and accretion of discount.
[2] Includes PIK capitalization and accretion of discount