v3.26.3
Portfolio Investments - Composition of Investment Portfolio (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Jun. 30, 2026
Sep. 30, 2025
Jun. 30, 2025
Schedule of Investments [Line Items]        
Cost $ 5,944,319 $ 6,315,369    
Investments at fair value 5,944,478 [1] 6,342,558 [2]    
First Lien, Unitranche        
Schedule of Investments [Line Items]        
Cost 63,005 219,582 $ 202,687 $ 201,585
Investments at fair value 58,579 155,717 $ 146,873 $ 166,464
First Lien Revolving Line of Credit        
Schedule of Investments [Line Items]        
Cost 92,288 78,795    
Investments at fair value 82,317 72,378    
First Lien Debt        
Schedule of Investments [Line Items]        
Cost 4,154,259 4,494,789    
Investments at fair value 3,952,018 4,216,556    
Second Lien Revolving Line of Credit        
Schedule of Investments [Line Items]        
Cost 5,284 1,854    
Investments at fair value 5,284 1,854    
Second Lien Debt        
Schedule of Investments [Line Items]        
Cost 651,305 752,658    
Investments at fair value 568,779 577,354    
Unsecured Debt        
Schedule of Investments [Line Items]        
Cost 7,200 7,200    
Investments at fair value 5,213 5,195    
Subordinated Structured Notes        
Schedule of Investments [Line Items]        
Cost 0 2,108    
Investments at fair value 0 2,794    
Equity        
Schedule of Investments [Line Items]        
Cost 1,033,983 [3] 977,965 [4]    
Investments at fair value $ 1,330,867 [3] $ 1,466,427 [4]    
[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.
[3] Equity, unless specifically stated otherwise, includes our investments in preferred stock, common stock, membership interests, net profits interests, net operating income interests, net revenue interests, overriding royalty interests, escrows receivable, and warrants.
[4]     Equity, unless specifically stated otherwise, includes our investments in preferred stock, common stock, membership interests, net profits interests, net operating income interests, net revenue interests, overriding royalty interests, escrows receivable, and warrants.