v3.26.1
Fair Value Measurements - Inputs Used (Details)
$ in Millions
Dec. 31, 2025
USD ($)
Basis_points
rate
Dec. 31, 2024
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, available for sale, at fair value [1] $ 50.5 $ 24.2
Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value 121.8  
Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value 121.8  
Total, Privately-held Investments $ 172.3  
Discounted cash flow | Commercial mortgage loans | Minimum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.039  
Discounted cash flow | Commercial mortgage loans | Maximum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.120  
Discounted cash flow | Commercial mortgage loans | Weighted Average | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.048  
Discounted cash flow | Commercial mortgage loans | Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value $ 25.4  
Discounted cash flow | Middle market loans | Minimum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.070  
Discounted cash flow | Middle market loans | Maximum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.111  
Discounted cash flow | Middle market loans | Weighted Average | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.081  
Discounted cash flow | Middle market loans | Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value $ 24.1  
Discounted cash flow | Asset-backed | Minimum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.060  
Available-for-Sale, Measurement input 0.041  
Discounted cash flow | Asset-backed | Maximum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.070  
Available-for-Sale, Measurement input 0.041  
Discounted cash flow | Asset-backed | Weighted Average | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs 0.061  
Available-for-Sale, Measurement input 0.041  
Discounted cash flow | Asset-backed | Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value $ 67.5  
Privately-held Investments, available for sale, at fair value $ 16.3  
Matrix pricing | Privately-held investments, global corporate securities | Minimum | Level 3 | WAL spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input | Basis_points (13.0)  
Matrix pricing | Privately-held investments, global corporate securities | Minimum | Level 3 | Capital size spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input | Basis_points 25.0  
Matrix pricing | Privately-held investments, global corporate securities | Maximum | Level 3 | WAL spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input 8.1  
Matrix pricing | Privately-held investments, global corporate securities | Maximum | Level 3 | Capital size spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input | Basis_points 25.0  
Matrix pricing | Privately-held investments, global corporate securities | Weighted Average | Level 3 | WAL spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input (2.9)  
Matrix pricing | Privately-held investments, global corporate securities | Weighted Average | Level 3 | Capital size spread    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-Sale, Measurement input | Basis_points 25.0  
Matrix pricing | Privately-held investments, global corporate securities | Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, available for sale, at fair value $ 34.2  
Valuation Technique, Price of Comparable Business | Middle market loans | Minimum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs | rate 6.8  
Valuation Technique, Price of Comparable Business | Middle market loans | Maximum | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs | rate 6.8  
Valuation Technique, Price of Comparable Business | Middle market loans | Weighted Average | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading, Measurement inputs | rate 6.8  
Valuation Technique, Price of Comparable Business | Middle market loans | Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Privately-held Investments, at fair value $ 4.8  
[1] Privately-held investments, trading at fair value include related party investments totaling $4.8 million (2024 — $73.6 million).