v3.25.2
Portfolio Investments - Changes in Fair Value of Level 3 Investments (Details)
$ in Thousands
 12 Months Ended
Jun. 30, 2025
USD ($)
investment
Jun. 30, 2024
USD ($)
investment
Jun. 30, 2023
USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Number of assets transferred out of Level 3 to Level 2 | investment   7  
Number of assets transferred out of Level 2 to Level 3 | investment 1 3  
Amortized Cost $ 6,693,501 $ 7,447,174  
Fair Value 6,673,516 [1] 7,718,243 [2]  
First Lien, Unitranche      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Amortized Cost 201,585 22,359 $ 49,625
Fair Value 166,464 22,413 $ 48,332
Investments      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 7,668,592 7,717,450  
Net realized (losses) gains on investments (519,315) (417,648)  
Net change in unrealized (losses) gains (287,595) 262,078  
Net realized and unrealized (losses) gains (806,910) (155,570)  
Purchases of portfolio investments 796,359 629,951  
Payment-in-kind interest 94,636 134,505  
Accretion of discounts and premiums, net 6,820 5,570  
Decrease to Subordinated Structured Notes cost, net (77,660) (83,403)  
Repayments and sales of portfolio investments (1,026,420) (536,069)  
Transfers within Level 3 0    
Transfers out of Level 3 (190,193) (106,297)  
Transfers into Level 3 126,207 62,455  
Fair value, ending balance 6,591,431 7,668,592  
First Lien Revolving Line of Credit      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 86,544 58,058  
Net realized (losses) gains on investments 0 0  
Net change in unrealized (losses) gains (1,125) (963)  
Net realized and unrealized (losses) gains (1,125) (963)  
Purchases of portfolio investments 57,591 36,076  
Payment-in-kind interest 2,778 3,975  
Accretion of discounts and premiums, net 56 104  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments (15,538) (10,706)  
Transfers within Level 3 (48,755)    
Transfers out of Level 3 0 0  
Transfers into Level 3 0 0  
Fair value, ending balance 81,551 86,544  
First Lien Debt      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 4,519,816 4,295,314  
Net realized (losses) gains on investments (9,258) (72,795)  
Net change in unrealized (losses) gains (134,545) 13,833  
Net realized and unrealized (losses) gains (143,803) (58,962)  
Purchases of portfolio investments 578,939 517,356  
Payment-in-kind interest 89,671 125,387  
Accretion of discounts and premiums, net 5,511 3,474  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments (701,471) (318,911)  
Transfers within Level 3 10,706    
Transfers out of Level 3 (147,000) (83,297)  
Transfers into Level 3 126,207 39,455  
Fair value, ending balance $ 4,338,576 4,519,816  
Number of assets transferred out of Level 3 to Level 2 | investment 2    
Second Lien Revolving Line of Credit      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance $ 4,987 4,646  
Net realized (losses) gains on investments 0 0  
Net change in unrealized (losses) gains 160 333  
Net realized and unrealized (losses) gains 160 333  
Purchases of portfolio investments (5,147) 0  
Payment-in-kind interest 0 0  
Accretion of discounts and premiums, net 0 8  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments 0 0  
Transfers within Level 3 0    
Transfers out of Level 3 0 0  
Transfers into Level 3 0 0  
Fair value, ending balance 0 4,987  
Second Lien Debt      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 1,038,882 1,257,862  
Net realized (losses) gains on investments (81,838) (179,986)  
Net change in unrealized (losses) gains (20,233) 147,658  
Net realized and unrealized (losses) gains (102,071) (32,328)  
Purchases of portfolio investments 55,694 (14,791)  
Payment-in-kind interest 2,187 5,143  
Accretion of discounts and premiums, net 1,253 1,984  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments (227,569) (178,988)  
Transfers within Level 3 1,189    
Transfers out of Level 3 (43,193) (23,000)  
Transfers into Level 3 0 23,000  
Fair value, ending balance $ 726,372 1,038,882  
Number of assets transferred out of Level 3 to Level 2 | investment 2    
Unsecured Debt      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance $ 7,200 7,200  
Net realized (losses) gains on investments 12 (1)  
Net change in unrealized (losses) gains (1,797) 0  
Net realized and unrealized (losses) gains (1,785) (1)  
Purchases of portfolio investments 0 0  
Payment-in-kind interest 0 0  
Accretion of discounts and premiums, net 0 0  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments (12) 1  
Transfers within Level 3 0    
Transfers out of Level 3 0 0  
Transfers into Level 3 0 0  
Fair value, ending balance 5,403 7,200  
Subordinated Structured Notes      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 531,690 665,002  
Net realized (losses) gains on investments (432,592) (159,113)  
Net change in unrealized (losses) gains 89,170 109,757  
Net realized and unrealized (losses) gains (343,422) (49,356)  
Purchases of portfolio investments 0 0  
Payment-in-kind interest 0 0  
Accretion of discounts and premiums, net 0 0  
Decrease to Subordinated Structured Notes cost, net (77,660) (83,403)  
Repayments and sales of portfolio investments (75,606) (553)  
Transfers within Level 3 0    
Transfers out of Level 3 0 0  
Transfers into Level 3 0 0  
Fair value, ending balance 35,002 531,690  
Distributions received, or entitled to be received, 84,604 119,125  
Effective yield interest income recognized 14,017 35,722  
Equity      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value, beginning balance 1,479,473 1,429,368  
Net realized (losses) gains on investments 4,361 (5,753)  
Net change in unrealized (losses) gains (219,225) (8,540)  
Net realized and unrealized (losses) gains (214,864) (14,293)  
Purchases of portfolio investments 109,282 91,310  
Payment-in-kind interest 0 0  
Accretion of discounts and premiums, net 0 0  
Decrease to Subordinated Structured Notes cost, net 0 0  
Repayments and sales of portfolio investments (6,224) (26,912)  
Transfers within Level 3 36,860    
Transfers out of Level 3 0 0  
Transfers into Level 3 0 0  
Fair value, ending balance $ 1,404,527 $ 1,479,473  
[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.