v3.26.1
REPORTABLE SEGMENT DATA - RECONCILIATION OF CAPITAL EXPENDITURES AND SEGMENT ASSETS TO CONSOLIDATED (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2025
Segment Reporting [Line Items]          
Assets $ 8,024,458   $ 8,024,458   $ 7,578,775
Corporate and other          
Segment Reporting [Line Items]          
Assets 1,617   1,617   (60,178)
Operating Segments          
Segment Reporting [Line Items]          
Capital expenditures 176,367 $ 156,905 550,061 $ 442,905  
Assets 8,022,841   8,022,841   7,638,953
Operating Segments | NJNG          
Segment Reporting [Line Items]          
Capital expenditures 132,937 103,402 345,856 306,638  
Assets 5,451,315   5,451,315   5,198,116
Operating Segments | CEV          
Segment Reporting [Line Items]          
Capital expenditures 26,590 49,276 157,969 117,978  
Assets 1,393,676   1,393,676   1,308,969
Operating Segments | ES          
Segment Reporting [Line Items]          
Capital expenditures 0 0 0 0  
Assets 108,655   108,655   98,429
Operating Segments | S&T          
Segment Reporting [Line Items]          
Capital expenditures 16,840 $ 4,227 46,236 $ 18,289  
Assets $ 1,069,195   $ 1,069,195   $ 1,033,439