v3.26.1
Fair Value Measurement and Disclosures - Schedule of the Valuation of the Company's Investments in the Fair Value Hierarchy Levels (Parenthetical) (Detail) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 2,101,797 $ 1,575,363
Investments Measured at NAV [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 754,696 [1],[2],[3] $ 662,962 [4],[5]
Investment, Type [Extensible Enumeration] Investment in Preferred Units of Liability Company [Member] Investment in Preferred Units of Liability Company [Member]
Unfunded commitments $ 64,869 $ 85,472
Investments Measured at NAV [Member] | Investment in Preferred Units of Liability Company [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 670,208 576,407
Series I [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 608,376 468,403
Series I [Member] | Investments Measured at NAV [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 218,450 [1],[2],[3] $ 197,120 [4],[5]
Investment, Type [Extensible Enumeration] Investment in Preferred Units of Liability Company [Member] Investment in Preferred Units of Liability Company [Member]
Unfunded commitments $ 18,777 $ 25,414
Series I [Member] | Investments Measured at NAV [Member] | Investment in Preferred Units of Liability Company [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 193,995 171,384
Series II [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 1,493,421 1,106,960
Series II [Member] | Investments Measured at NAV [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 536,246 [1],[2],[3] $ 465,842 [4],[5]
Investment, Type [Extensible Enumeration] Investment in Preferred Units of Liability Company [Member] Investment in Preferred Units of Liability Company [Member]
Unfunded commitments $ 46,092 $ 60,058
Series II [Member] | Investments Measured at NAV [Member] | Investment in Preferred Units of Liability Company [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 476,213 $ 405,023
[1] As of June 30, 2026, Series I, Series II and the Company had unfunded commitments of $18,777, $46,092, and $64,869, respectively, related to investments measured at NAV.
[2] Included within certain investments measured at NAV were Level III investments. Series I, Series II, and the Company Level III amounts of these investments were $193,995, $476,213, and $670,208, respectively.
[3] The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated statement of assets and liabilities.
[4] As of December 31, 2025, Series I, Series II and the Company had unfunded commitments of $25,414, $60,058, and $85,472, respectively, related to investments measured at NAV
[5] Included within certain investments measured at NAV were Level III investments. Series I, Series II and the Company Level III amounts of these investments were $171,384, $405,023, and $576,407, respectively