v3.26.1
Portfolio Investments - Industries and Geographical Locations Comprising Greater than 10% of Portfolio Fair Value (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Concentration Risk [Line Items]    
Cost $ 6,315,369 $ 6,693,501
Fair Value $ 6,342,558 [1] $ 6,673,516 [2]
Investments at Fair Value | Industry Concentration Risk    
Concentration Risk [Line Items]    
% of Portfolio 100.00% 100.00%
Consumer Finance    
Concentration Risk [Line Items]    
Cost $ 760,592 $ 741,932
Fair Value $ 1,149,153 $ 953,320
Consumer Finance | Investments at Fair Value | Industry Concentration Risk    
Concentration Risk [Line Items]    
% of Portfolio 18.10% 14.30%
Equity Real Estate Investment Trusts (REITs)    
Concentration Risk [Line Items]    
Cost $ 896,889 $ 922,647
Fair Value $ 1,081,596 $ 1,300,972
Equity Real Estate Investment Trusts (REITs) | Investments at Fair Value | Industry Concentration Risk    
Concentration Risk [Line Items]    
% of Portfolio 17.10% 19.50%
Health Care Providers & Services    
Concentration Risk [Line Items]    
Cost $ 776,917 $ 767,993
Fair Value $ 758,688 $ 731,527
Health Care Providers & Services | Investments at Fair Value | Industry Concentration Risk    
Concentration Risk [Line Items]    
% of Portfolio 12.00% 11.00%
All Other Industries    
Concentration Risk [Line Items]    
Cost $ 3,880,971 $ 4,260,929
Fair Value $ 3,353,121 $ 3,687,697
All Other Industries | Investments at Fair Value | Industry Concentration Risk    
Concentration Risk [Line Items]    
% of Portfolio 52.80% 55.20%
[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.