v3.26.1
REVENUE - DISAGGREGATED REVENUE - TYPE (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers $ 641,350 $ 569,199 $ 1,082,249 $ 928,152
Revenues out of scope 298,051 343,828 462,006 473,236
Total operating revenues 939,401 913,027 1,544,255 1,401,388
Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 459,341 407,080 759,423 648,553
Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 136,098 118,570 239,836 205,609
Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 43,841 42,408 78,518 69,733
Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 2,070 1,141 4,472 4,257
Operating Segments        
Disaggregation of Revenue [Line Items]        
Total operating revenues 924,443 898,004 1,513,291 1,370,732
NJNG | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 574,584 509,145 949,205 805,210
Revenues out of scope 66,338 109,194 101,618 146,557
Total operating revenues 640,922 618,339 1,050,823 951,767
NJNG | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 444,413 392,100 728,514 615,919
NJNG | Operating Segments | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 84,260 73,496 137,701 115,301
NJNG | Operating Segments | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 43,841 42,408 78,518 69,733
NJNG | Operating Segments | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 2,070 1,141 4,472 4,257
CEV | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 8,883 7,833 18,235 16,555
Revenues out of scope 1,049 134 23,457 17,818
Total operating revenues 9,932 7,967 41,692 34,373
CEV | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 2,110
CEV | Operating Segments | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 8,883 7,833 18,235 14,445
CEV | Operating Segments | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
CEV | Operating Segments | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
ES        
Disaggregation of Revenue [Line Items]        
Total operating revenues 4,900 4,900 9,900 9,900
ES | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 13,491 11,890 26,331 23,837
Revenues out of scope 230,664 234,500 336,931 308,861
Total operating revenues 244,155 246,390 363,262 332,698
ES | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
ES | Operating Segments | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 13,491 11,890 26,331 23,837
ES | Operating Segments | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
ES | Operating Segments | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
S&T | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 29,434 25,308 57,514 51,894
Revenues out of scope 0 0 0 0
Total operating revenues 29,434 25,308 57,514 51,894
S&T | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
S&T | Operating Segments | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 29,434 25,308 57,514 51,894
S&T | Operating Segments | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
S&T | Operating Segments | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
HSO | HSO        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 14,958 15,023 30,964 30,656
Revenues out of scope 0 0 0 0
Total operating revenues 14,958 15,023 30,964 30,656
HSO | HSO | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 14,928 14,980 30,909 30,524
HSO | HSO | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 30 43 55 132
HSO | HSO | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 0 0 0 0
HSO | HSO | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers $ 0 $ 0 $ 0 $ 0