v3.26.1
Portfolio Investments - Fair Value of Investments (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value $ 6,342,558 [1] $ 6,673,516 [2]  
Derivative Instruments      
Derivative Assets, at fair value (Note 6) 18,900 0  
Total Foreign currency forward contracts - Assets 18,900    
Total Foreign currency forward contracts - Liabilities 0    
Investment , cost 6,315,369 6,693,501  
Foreign Exchange Forward      
Derivative Instruments      
Derivative Assets, at fair value (Note 6) 18,900    
Foreign currency forward contracts - Liabilities 0    
Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Derivative Instruments      
Total Foreign currency forward contracts - Assets 0    
Total Foreign currency forward contracts - Liabilities 0    
Level 1 | Foreign Exchange Forward      
Derivative Instruments      
Derivative Assets, at fair value (Note 6) 0    
Foreign currency forward contracts - Liabilities 0    
Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,233 82,085  
Derivative Instruments      
Total Foreign currency forward contracts - Assets 18,900    
Total Foreign currency forward contracts - Liabilities 0    
Level 2 | Foreign Exchange Forward      
Derivative Instruments      
Derivative Assets, at fair value (Note 6) 18,900    
Foreign currency forward contracts - Liabilities 0    
Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 6,341,325 6,591,431  
Derivative Instruments      
Total Foreign currency forward contracts - Assets 0    
Total Foreign currency forward contracts - Liabilities 0    
Level 3 | Foreign Exchange Forward      
Derivative Instruments      
Derivative Assets, at fair value (Note 6) 0    
Foreign currency forward contracts - Liabilities 0    
First Lien Revolving Line of Credit      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 72,378 81,551  
First Lien Revolving Line of Credit | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
First Lien Revolving Line of Credit | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
First Lien Revolving Line of Credit | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 72,378 81,551  
First Lien Debt      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 4,216,556 4,381,227  
First Lien Debt | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
First Lien Debt | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,192 42,651  
First Lien Debt | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 4,215,364 4,338,576  
First Lien, Unitranche      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 155,717 166,464 $ 22,413
Derivative Instruments      
Investment , cost 219,582 201,585 $ 22,359
Second Lien Revolving Line of Credit      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,854 0  
Second Lien Revolving Line of Credit | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Second Lien Revolving Line of Credit | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Second Lien Revolving Line of Credit | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,854 0  
Second Lien Debt      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 577,354 765,806  
Second Lien Debt | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Second Lien Debt | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 41 39,434  
Second Lien Debt | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 577,313 726,372  
Unsecured Debt      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 5,195 5,403  
Unsecured Debt | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Unsecured Debt | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Unsecured Debt | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 5,195 5,403  
Subordinated Structured Notes      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 2,794 35,002  
Subordinated Structured Notes | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Subordinated Structured Notes | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Subordinated Structured Notes | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 2,794 35,002  
Equity      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,466,427 1,404,527  
Equity | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Equity | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Equity | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value $ 1,466,427 $ 1,404,527  
[1] Fair value is determined by or under the direction of our Board of Directors. Unless otherwise indicated by endnote 42 below, all of our investments are valued using significant unobservable inputs. In accordance with ASC 820, such investments are classified as Level 3 within the fair value hierarchy. See Notes 2 and 3 within the accompanying notes to consolidated financial statements for further discussion.
[2] Fair value is determined by or under the direction of our Board of Directors. Unless otherwise indicated by endnote 42 below, all of our investments are valued using significant unobservable inputs. In accordance with ASC 820, such investments are classified as Level 3 within the fair value hierarchy. See Notes 2 and 3 within the accompanying notes to consolidated financial statements for further discussion.