v3.26.1
Variable Interest Entities - Not Primary Beneficiary (Detail) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Feb. 28, 2025
Dec. 31, 2024
Jun. 02, 2022
Investments in and Advances to Affiliates [Line Items]                
Carrying value of investment $ 71,276 $ 70,986 $ 69,638 $ 29,628 $ 33,555   $ 35,532  
NGP ET IV                
Investments in and Advances to Affiliates [Line Items]                
Carrying value of investment 18,000   13,400          
NGP ET IV                
Investments in and Advances to Affiliates [Line Items]                
Funding commitment 12,400             $ 25,000
Gavin Generation                
Investments in and Advances to Affiliates [Line Items]                
Funding commitment 17,400         $ 25,000    
Carrying value of investment $ 33,200   $ 35,200          
VIE, Not Primary Beneficiary | NGP ET IV | NGP ET IV                
Investments in and Advances to Affiliates [Line Items]                
Ownership percentage by limited partners 3.60%              
VIE, Not Primary Beneficiary | Gavin Generation | Gavin Generation                
Investments in and Advances to Affiliates [Line Items]                
Ownership percentage by limited partners 5.40%