v3.26.3
Fair Value Measurement and Disclosures - Additional Information (Details) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value $ 2,001,134,000   $ 2,001,134,000   $ 1,577,705,000
Transfers out of Level III   $ 0      
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss)  
Unrealized gain (loss) on investments $ (10,793,000) $ 1,581,000 $ (21,446,000) $ 736,000  
Series I          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value 312,998,000   312,998,000   305,789,000
Transfers into Level III   $ 34,264,000   34,264,000  
Transfers out of Level III $ (11,141,000)   $ (11,468,000) $ (27,000)  
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss)  
Unrealized gain (loss) on investments $ (1,718,000) $ (1,237,000) $ (4,015,000) $ (2,359,000)  
Series II          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value 1,688,136,000   1,688,136,000   1,271,916,000
Transfers into Level III   $ 106,214,000   106,214,000  
Transfers out of Level III $ (46,350,000)   $ (47,702,000) $ (67,000)  
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss)  
Unrealized gain (loss) on investments $ (9,075,000) $ 344,000 $ (17,431,000) $ 3,095,000  
Level I | Money Market Funds          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Cash and cash equivalents 14,168,000   14,168,000   3,502,000
Level I | Series I          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Cash and cash equivalents 1,831,000   1,831,000   640,000
Level I | Series II          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Cash and cash equivalents 12,337,000   12,337,000   2,862,000
Level III          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value 1,414,187,000   1,414,187,000   1,023,351,000
Transfers into Level III 0 140,478,000 0 140,478,000  
Transfers out of Level III (57,491,000) 0 (59,170,000) (94,000)  
Unrealized gain (loss) on investments (10,793,000) (1,581,000) (21,446,000) 736,000  
Level III | Series I          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value 221,194,000   221,194,000   198,345,000
Transfers into Level III 0 34,264,000 0 34,264,000  
Transfers out of Level III (11,141,000) 0 (11,468,000) (27,000)  
Unrealized gain (loss) on investments (1,718,000) (1,237,000) (4,015,000) (2,359,000)  
Level III | Series II          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Investments at fair value 1,192,993,000   1,192,993,000   $ 825,006,000
Transfers into Level III 0 106,214,000 0 106,214,000  
Transfers out of Level III (46,350,000) 0 (47,702,000) (67,000)  
Unrealized gain (loss) on investments $ (9,075,000) $ (344,000) $ (17,431,000) $ 3,095,000