v3.26.3
Derivative Instruments - Schedule of Fair Value and Notional Value of the Derivative Assets and Liabilities (Details)
€ in Thousands, £ in Thousands, $ in Thousands, $ in Thousands, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Sep. 30, 2026
AUD ($)
Sep. 30, 2026
CAD ($)
Sep. 30, 2026
EUR (€)
Sep. 30, 2026
GBP (£)
Sep. 03, 2026
USD ($)
Aug. 20, 2026
USD ($)
Jun. 05, 2026
USD ($)
Jan. 23, 2026
USD ($)
Dec. 31, 2025
AUD ($)
Dec. 31, 2025
CAD ($)
Dec. 31, 2025
EUR (€)
Dec. 31, 2025
GBP (£)
Jan. 21, 2025
USD ($)
Apr. 04, 2024
USD ($)
Derivatives not designated as hedges:                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Assets $ 1,088,281 $ 630,482                            
Liabilities (1,079,175) (632,423)                            
Unsecured debt investments | Derivatives designated as hedges:                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Unsecured notes, carrying value 2,700,000 1,400,000                            
Increase to carrying value of the notes (57,600) 27,800                            
Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 2,800,000 1,350,000                            
Assets (57,398) 18,081                            
Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges:                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Assets 0 26,732                            
Liabilities (57,398) 0                            
Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Assets 0 14,619                            
Liabilities (11,565) 0                            
Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Regions Bank                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Assets 0 0                            
Liabilities (34,203) 0                            
Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Assets 0 12,113                            
Liabilities (11,630) 0                            
Interest rate swaps April 2029 Notes | Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 700,000 700,000 [1]                           $ 700,000
Assets (11,565) 5,968 [1]                            
Interest rate swaps April 2029 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 700,000 700,000                            
Assets 0 14,619                            
Liabilities (11,565) 0                            
Interest rate swaps October 2029 Notes | Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 500,000             $ 400,000 $ 500,000              
Assets (11,049)                              
Interest rate swaps October 2029 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Regions Bank                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 500,000 0                            
Assets 0 0                            
Liabilities (11,049) 0                            
Interest rate swaps October 2029 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 400,000 0                            
Assets 0 0                            
Liabilities (8,001) 0                            
Interest rate swaps January 2031 Notes | Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 400,000                 $ 400,000            
Assets (18,938)                              
Interest rate swaps January 2031 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Regions Bank                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 400,000 0                            
Assets 0 0                            
Liabilities (18,938) 0                            
September 2032 Notes | Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 150,000           $ 150,000                  
Assets (4,216)                              
September 2032 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | Regions Bank                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 150,000 0                            
Assets 0 0                            
Liabilities (4,216) 0                            
Interest rate swaps March 2028 Notes | Interest Rate Swaps | Unsecured debt investments                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 650,000 650,000 [2]                         $ 650,000  
Assets (3,629) 12,113 [2]                            
Interest rate swaps March 2028 Notes | Interest Rate Swaps | Unsecured debt investments | Derivatives designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 650,000 650,000                            
Assets 0 12,113                            
Liabilities (3,629) 0                            
Foreign currency forward contract AUD | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount     $ 12,910               $ 12,910          
Assets 9,012 8,405                            
Liabilities (8,966) (8,616)                            
Foreign Currency Forward Contract CAD | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount       $ 56,106               $ 0        
Assets 40,873 0                            
Liabilities (39,450) 0                            
Foreign Currency Forward Contract CAD | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount       $ 3,343               $ 0        
Assets 2,403 0                            
Liabilities (2,379) 0                            
Foreign currency forward contract EUR | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | €         € 0               € 282,460      
Assets 0 334,694                            
Liabilities 0 (334,694)                            
Foreign currency forward contract EUR | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | €         62,371               62,371      
Assets 71,989 73,074                            
Liabilities (71,199) (73,889)                            
Foreign currency forward contract EUR | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Royal Bank of Canada                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | €         € 318,412               € 0      
Assets 368,227 0                            
Liabilities (363,490) 0                            
Foreign currency forward contract GBP | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Goldman Sachs Bank USA                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | £           £ 0               £ 147,230    
Assets 0 197,770                            
Liabilities 0 (198,381)                            
Foreign currency forward contract GBP | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | £           25,000               12,500    
Assets 33,433 16,539                            
Liabilities (33,178) (16,843)                            
Foreign currency forward contract GBP | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Royal Bank of Canada                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount | £           £ 272,570               £ 0    
Assets 364,959 0                            
Liabilities (361,723) 0                            
Foreign Currency Forward Contract USD | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | SMBC Capital Markets, Inc.                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 16,700 0                            
Assets 16,583 0                            
Liabilities (16,700) 0                            
Foreign Currency Forward Contract USD | Forward Contracts | Unsecured debt investments | Derivatives not designated as hedges: | Royal Bank of Canada                                
Derivative Instruments and Hedging Activities Disclosures [Line Items]                                
Notional amount 182,090 0                            
Assets 180,802 0                            
Liabilities $ (182,090) $ 0                            
[1] The Company has an ISDA agreement with Goldman Sachs Bank USA.
[2] The Company has an ISDA agreement with SMBC Capital Markets, Inc.
Forward Contracts as of December 31, 2025
Notional Amount to be PurchasedNotional Amount to be SoldCounterpartySettlement DateUnrealized Appreciation / (Depreciation)
Foreign currency forward contract$197,770 £147,230 Goldman Sachs Bank USA1/20/2026$(611)
Foreign currency forward contract$16,539 £12,500 SMBC Capital Markets, Inc.1/20/2026(304)
Foreign currency forward contract$6,296 €5,301 SMBC Capital Markets, Inc.7/17/202615 
Foreign currency forward contract$334,694 €282,462 Goldman Sachs Bank USA7/17/2026— 
Foreign currency forward contract$66,778 €57,070 SMBC Capital Markets, Inc.7/17/2026(830)
Foreign currency forward contract$8,405 A$12,910 Goldman Sachs Bank USA1/20/2026(211)
Total$(1,941)