v3.26.1
Borrowings - Additional Information (Details)
€ in Millions
1 Months Ended 3 Months Ended
Aug. 31, 2023
Mar. 31, 2026
USD ($)
Mar. 31, 2025
USD ($)
Mar. 31, 2026
EUR (€)
Dec. 31, 2025
USD ($)
Jun. 30, 2021
USD ($)
May 31, 2021
USD ($)
Mar. 31, 2014
USD ($)
Mar. 31, 2013
USD ($)
Debt Instrument [Line Items]                  
Interest   $ 38,600,000 $ 27,800,000            
Borrowings   3,033,700,000     $ 3,025,100,000        
Fair value of collateralized loan obligation assets   $ 12,000,000,000.0     11,000,000,000.0        
Senior Notes                  
Debt Instrument [Line Items]                  
Debt redemption price percentage (percent)   100.00%              
CLO Borrowings                  
Debt Instrument [Line Items]                  
Interest   $ 4,200,000 3,800,000            
Borrowings   358,700,000     350,100,000        
CLO Financing Facility                  
Debt Instrument [Line Items]                  
Outstanding borrowings   $ 337,200,000   € 292.2          
5.650% Senior Notes Due 9/15/2048                  
Debt Instrument [Line Items]                  
Interest rate (percent)   5.65%   5.65%          
Borrowings   $ 350,000,000.0     350,000,000.0        
5.650% Senior Notes Due 9/15/2048 | Senior Notes                  
Debt Instrument [Line Items]                  
Borrowings   350,000,000.0              
Fair value of debt   $ 330,400,000     347,500,000        
5.650% Senior Notes Due 9/15/2048 | Treasury rate | Senior Notes                  
Debt Instrument [Line Items]                  
Discount rate, spread on variable rate   0.40%              
5.625% Senior Notes Due 3/30/2043                  
Debt Instrument [Line Items]                  
Interest rate (percent)   5.625%   5.625%          
Borrowings   $ 600,000,000.0     600,000,000.0        
5.625% Senior Notes Due 3/30/2043 | Senior Notes                  
Debt Instrument [Line Items]                  
Borrowings   600,000,000.0           $ 200,000,000.0 $ 400,000,000.0
Fair value of debt   $ 574,100,000     600,700,000        
5.625% Senior Notes Due 3/30/2043 | Treasury rate | Senior Notes                  
Debt Instrument [Line Items]                  
Discount rate, spread on variable rate   0.40%              
5.050% Senior Notes Due 9/19/2035                  
Debt Instrument [Line Items]                  
Interest rate (percent)   5.05%   5.05%          
Borrowings   $ 800,000,000.0     800,000,000.0        
5.050% Senior Notes Due 9/19/2035 | Senior Notes                  
Debt Instrument [Line Items]                  
Interest rate (percent)   5.05%   5.05%          
Borrowings   $ 800,000,000.0              
Fair value of debt   $ 774,200,000     800,900,000        
5.050% Senior Notes Due 9/19/2035 | Treasury rate | Senior Notes                  
Debt Instrument [Line Items]                  
Discount rate, spread on variable rate   0.20%              
3.500% Senior Notes Due 9/19/2029                  
Debt Instrument [Line Items]                  
Interest rate (percent)   3.50%   3.50%          
Borrowings   $ 425,000,000.0     425,000,000.0        
3.500% Senior Notes Due 9/19/2029 | Senior Notes                  
Debt Instrument [Line Items]                  
Interest rate (percent)   3.50%   3.50%          
Borrowings   $ 425,000,000.0              
Fair value of debt   $ 410,300,000     417,800,000        
3.500% Senior Notes Due 9/19/2029 | Treasury rate | Senior Notes                  
Debt Instrument [Line Items]                  
Discount rate, spread on variable rate   0.30%              
4.625% Subordinated Notes Due 5/15/2061                  
Debt Instrument [Line Items]                  
Interest   $ 5,900,000 5,900,000            
Debt redemption price percentage (percent)   102.00%              
Interest rate (percent)   4.625%   4.625%     4.625%    
Borrowings   $ 500,000,000.0     500,000,000.0 $ 65,000,000.0 $ 435,000,000.0    
Period from tax redemption event that debt may be redeemed (in days)   120 days              
Period from rating agency event that debt may be redeemed (in days)   90 days              
Fair value of debt   $ 350,000,000.0     342,000,000.0        
Revolving Credit Facility                  
Debt Instrument [Line Items]                  
Borrowing capacity   $ 1,000,000,000.0              
Interest rate under credit facility (percent)   4.76%   4.76%          
Borrowings under credit facilities   $ 0 0            
Outstanding borrowings   0              
Fair value of debt   $ 51,000,000.0     $ 63,000,000.0        
Revolving Credit Facility | Base rate                  
Debt Instrument [Line Items]                  
Margin spread on interest rate (percent)   0.50%              
Revolving Credit Facility | SOFR                  
Debt Instrument [Line Items]                  
Margin spread on interest rate (percent)   0.10%              
Revolving Credit Facility | SOFR | Maximum                  
Debt Instrument [Line Items]                  
Margin spread on interest rate (percent)   1.50%              
Revolving Credit Facility | Global Credit Revolving Credit Facility                  
Debt Instrument [Line Items]                  
Borrowings under credit facilities     $ 0            
Outstanding borrowings   $ 0              
Revolving Credit Facility | Global Credit Revolving Credit Facility | Base rate                  
Debt Instrument [Line Items]                  
Margin spread on interest rate (percent) 1.00%                
Revolving Credit Facility | Global Credit Revolving Credit Facility | SOFR                  
Debt Instrument [Line Items]                  
Margin spread on interest rate (percent)   2.00%              
Revolving Credit Facility | Global Credit Revolving Credit Facility Maturing in 2027                  
Debt Instrument [Line Items]                  
Borrowing capacity   $ 300,000,000              
Revolving Credit Facility | Global Credit Revolving Credit Facility Maturing in 2026                  
Debt Instrument [Line Items]                  
Borrowing capacity   $ 200,000,000