v3.26.1
REVENUE - DISAGGREGATED REVENUE - TYPE (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers $ 257,985 $ 234,836 $ 1,340,234 $ 1,162,987
Revenues out of scope 91,195 64,110 553,201 537,347
Total operating revenues 349,180 298,946 1,893,435 1,700,334
Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 134,345 130,985 893,768 779,537
Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 95,565 78,797 335,401 284,406
Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 26,023 22,011 104,541 91,744
Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 2,052 3,043 6,524 7,300
Operating Segments        
Disaggregation of Revenue [Line Items]        
Total operating revenues 331,427 282,799 1,844,718 1,653,532
NJNG | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 171,766 167,902 1,120,971 973,112
Revenues out of scope 29,103 36,888 130,721 183,446
Total operating revenues 200,869 204,790 1,251,692 1,156,558
NJNG | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 116,616 114,878 845,130 730,797
NJNG | Operating Segments | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 27,075 27,970 164,776 143,271
NJNG | Operating Segments | Firm transportation        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 26,023 22,011 104,541 91,744
NJNG | Operating Segments | Interruptible, off-tariff and other        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 2,052 3,043 6,524 7,300
CEV | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 19,024 11,851 37,259 28,406
Revenues out of scope 154 179 23,611 17,997
Total operating revenues 19,178 12,030 60,870 46,403
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 19,024 11,851 37,259 26,296
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 14,800 14,800
ES | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 18,024 11,807 44,355 35,644
Revenues out of scope 61,938 27,043 398,869 335,904
Total operating revenues 79,962 38,850 443,224 371,548
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 18,024 11,807 44,355 35,644
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 31,418 27,129 88,932 79,023
Revenues out of scope 0 0 0 0
Total operating revenues 31,418 27,129 88,932 79,023
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 31,418 27,129 88,932 79,023
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 17,753 16,147 48,717 46,802
Revenues out of scope 0 0 0 0
Total operating revenues 17,753 16,147 48,717 46,802
HSO | HSO | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 17,729 16,107 48,638 46,630
HSO | HSO | Commercial and industrial        
Disaggregation of Revenue [Line Items]        
Revenues from contracts with customers 24 40 79 172
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