v3.25.1
Financing Arrangements - Narrative (Details)
€ in Millions, £ in Millions, $ in Millions, $ in Millions, $ in Millions
3 Months Ended 12 Months Ended
Mar. 27, 2025
Mar. 15, 2025
Mar. 31, 2025
USD ($)
Mar. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
Mar. 31, 2025
EUR (€)
Mar. 31, 2025
GBP (£)
Mar. 28, 2025
USD ($)
Jan. 15, 2025
USD ($)
Dec. 31, 2024
EUR (€)
Dec. 31, 2024
GBP (£)
Dec. 31, 2024
AUD ($)
Dec. 31, 2024
CAD ($)
Jun. 15, 2019
Jun. 14, 2019
Debt Instrument [Line Items]                              
Asset coverage per ratio (as percent)     182.00% 185.00%   182.00% 182.00%                
Long term outstanding     $ 8,009.0 $ 7,968.0 $ 7,385.0                    
Average outstanding amount     $ 7,829.0 $ 8,214.0                      
Weighted average interest rate (as percent)     5.50% 5.43%   5.50% 5.50%                
Effective interest rate percentage (as percent)     5.48% 5.35%   5.48% 5.48%                
Senior Secured Revolving Credit Facility                              
Debt Instrument [Line Items]                              
Principal amount               $ 380.0              
Notional value                 $ 121.2            
Class A-1 Senior Secured Floating Rate Notes | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 160.0              
Rate, basis spread on variable rate               1.48%              
Class A-1L Senior Secured Floating Rate Loans | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 100.0              
Rate, basis spread on variable rate               1.48%              
Class A-1W Senior Secured Floating Rate Loans | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 30.0              
Rate, basis spread on variable rate               1.48%              
Class A-2 Senior Secured Floating Rate Notes | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 0.0              
Rate, basis spread on variable rate               1.60%              
Class A-2L Senior Secured Floating Rate Loans | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 20.0              
Rate, basis spread on variable rate               1.60%              
Class B Senior Secured Floating Rate Notes | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 30.0              
Rate, basis spread on variable rate               1.75%              
Class C Secured Deferrable Floating Rate Notes | Senior Notes                              
Debt Instrument [Line Items]                              
Principal amount               $ 40.0              
Rate, basis spread on variable rate               2.15%              
8.625% Notes due 2025 | Unsecured Notes                              
Debt Instrument [Line Items]                              
Long term outstanding         $ 250.0                    
Stated interest rate (as percent)   8.625% 8.625% 8.625% 8.625% 8.625% 8.625%     8.625% 8.625% 8.625% 8.625%    
Debt instrument, redemption price (as percent)   100.00%                          
Revolving Credit Facility | Meadowbrook Run Credit Facility | Line of Credit                              
Debt Instrument [Line Items]                              
Long term outstanding     $ 260.0   $ 200.0                    
Basis spread on variable rate (as percent) 1.95%   1.95%   2.70%                    
Amortization period (as percent) 2.45%                            
Stated interest rate (as percent) 0.00%                            
Adjusted unused commitment fees (as percent) 0.65%                            
Revolving Credit Facility | Senior Secured Revolving Credit Facility                              
Debt Instrument [Line Items]                              
Long term outstanding                   € 455 £ 165 $ 4 $ 3    
Revolving Credit Facility | Senior Secured Revolving Credit Facility | Line of Credit                              
Debt Instrument [Line Items]                              
Long term outstanding     $ 1,997.0   $ 628.0 € 485 £ 416                
Investment Advisory Agreement | FS/KKR Advisor, LLC                              
Debt Instrument [Line Items]                              
Asset coverage per ratio (as percent)                           150.00% 200.00%