v3.26.1
FAIR VALUE - ADDITIONAL INFORMATION (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Sep. 30, 2025
NJNG    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Finance leases $ 43,600 $ 33,500
Level 2 | NJNG    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Finance leases 42,500 32,500
Fair market value | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value 2,561,682 2,631,512
Solar Asset Financing | CEV    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value 498,800 471,500
Solar Asset Financing | Fair market value | CEV    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value $ 501,900 $ 481,400