v3.26.1
Debt and Foreign Currency Transactions and Translations - Additional Information (Details) - USD ($)
6 Months Ended
Mar. 09, 2026
Dec. 19, 2025
Dec. 08, 2025
Nov. 25, 2025
Aug. 12, 2025
Sep. 19, 2024
Jul. 19, 2024
Dec. 09, 2022
Apr. 07, 2022
Mar. 11, 2022
Jan. 07, 2022
Jun. 30, 2026
Mar. 06, 2026
Dec. 31, 2025
Jun. 30, 2025
Oct. 17, 2024
Oct. 12, 2023
Jun. 07, 2022
Debt Instrument [Line Items]                                    
Asset coverage percentage                       213.90%   255.20% 286.70%      
Available remaining capacity                       $ 4,212,692,000 [1]   $ 3,357,068,000 [2]        
Cardinal Funding LLC                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity                       1,200,000,000   1,200,000,000        
Available remaining capacity [1]                       $ 120,000,000            
Minimum                                    
Debt Instrument [Line Items]                                    
Required assets coverage percentage                       150.00%            
Senior Secured Facility                                    
Debt Instrument [Line Items]                                    
Required assets coverage percentage                       150.00%            
Maximum borrowing capacity         $ 3,453,000,000         $ 1,835,000,000   $ 3,828,000,000 $ 3,828,000,000 3,453,000,000   $ 2,740,000,000 $ 2,185,000,000 $ 2,085,000,000.000
Available remaining capacity                       3,791,318,000 [1]   3,157,068,000 [2]        
Standby letters of credit issued                       $ 36,682   $ 23,735,000        
Available facility to extended borrowing capacity under new or existing credit facility         $ 5,180,000,000                     $ 4,110,000,000 $ 3,278,000,000 $ 2,753,000,000
Unused commitment fee percentage         0.325%         0.375%                
Senior Secured Facility | Base Rate | Scenario One                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       0.525%            
Senior Secured Facility | Base Rate | Scenario Two                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       0.65%            
Senior Secured Facility | Base Rate | Scenario Three                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       0.775%            
Senior Secured Facility | SOFR | Scenario One                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       1.525%            
Senior Secured Facility | SOFR | Scenario Two                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       1.65%            
Senior Secured Facility | SOFR | Scenario Three                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       1.775%            
Senior Secured Facility | SOFR Credit Spread Adjustment                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       0.10%            
Cardinal Funding Secured Credit Facility                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity     $ 1,200,000,000         $ 800,000,000     $ 500,000,000 $ 500,000,000            
Debt instrument expiration reinvestment term                       3 years            
Debt additional aggregate commitment credit facility                 $ 1,350,000,000   750,000,000              
Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, basis spread prior to commitment termination date     1.70%         2.75%                    
Debt instrument, basis spread after commitment termination date               3.25%                    
Cardinal Funding Secured Credit Facility | Applicable Reference Rate | Maximum                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       0.50%            
Mallard Funding Loan and Servicing Agreement                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity       $ 900,000,000             $ 500,000,000 $ 500,000,000            
Percentage during reinvestment period           2.00%                        
Percentage during amortization period           2.25%                        
Debt instrument, spread on applicable referrence rate       1.80%                            
Maximum advance rate       67.50%             65.00%              
Toucan Funding Credit Agreement                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity   $ 600,000,000                   1,000,000,000            
Toucan Funding Credit Agreement | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate   1.60%                                
Debt instrument, spread on applicable referrence rate   0.125%                                
Bald Eagle Funding Credit Agreement                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity $ 500,000,000                                  
Line of credit facility expiration period 3 years                                  
Bald Eagle Funding Credit Agreement | SOFR                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate 1.35%                                  
Letter of Credit                                    
Debt Instrument [Line Items]                                    
Maximum borrowing capacity                       $ 200,000,000            
Broadly Syndicated Loans | Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate     1.45%                              
Broadly Syndicated Loans | Cardinal Funding Secured Credit Facility | SOFR Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on applicable referrence rate                       1.70%            
Broadly Syndicated Loans | Mallard Funding Loan and Servicing Agreement                                    
Debt Instrument [Line Items]                                    
Ramp up period                       9 months            
Broadly Syndicated Loans | Mallard Funding Loan and Servicing Agreement | Mallard Funding Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, basis spread prior to commitment termination date                       2.00%            
Debt instrument, basis spread after commitment termination date                       2.25%            
Debt instrument, spread on variable rate                       1.60%            
Private Credit Loans | Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate     1.85%                              
Private Credit Loans | Cardinal Funding Secured Credit Facility | SOFR Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       2.20%            
Private Credit Loans | Mallard Funding Loan and Servicing Agreement                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on applicable referrence rate       1.85%                            
Other Eligible Loans | Cardinal Funding Secured Credit Facility | SOFR Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                       2.45%            
Financial Bonds | Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate                 2.00%                  
Middle Market Loans | Mallard Funding Loan and Servicing Agreement | Mallard Funding Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Debt instrument, basis spread prior to commitment termination date                       2.00%            
Debt instrument, basis spread after commitment termination date                       2.25%            
Bonds or Loans | Applicable Reference Rate | Cardinal Funding LLC                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on variable rate             1.60%                      
Diversity Score 20 or Greater and Less than 25 | Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Maximum advance rate     67.50%                              
Diversity Score 25 or Greater | Cardinal Funding Secured Credit Facility | Applicable Reference Rate                                    
Debt Instrument [Line Items]                                    
Maximum advance rate     70.00%                              
Liquid Credit Loan | Mallard Funding Loan and Servicing Agreement                                    
Debt Instrument [Line Items]                                    
Debt instrument, spread on applicable referrence rate       1.60%                            
Unsecured Notes Due 2028                                    
Debt Instrument [Line Items]                                    
Frequency of periodic payments                       semi-annually            
[1] The amount available reflects any limitations related to each respective credit facility’s borrowing base.
[2] The amount available reflects any limitations related to each respective credit facility’s borrowing base.