v3.26.1
Business Segment Data - Schedule of Segment Reporting Information (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Abstract]            
Number Of Reportable Segments Not Disclosed Flag         reportable segments  
Segment Reporting [Line Items]            
Operating revenues  $ 375,303   $ 351,186   $ 981,280 $ 1,026,019
Purchased natural gas sold 93,538   96,057   332,929 413,214
Electric fuel and purchased power 38,674   34,891   84,741 78,639
Operation and maintenance 114,016   112,887   228,921 223,934
Depreciation and amortization 55,183   51,853   109,362 103,114
Taxes, other than income 25,947   25,166   61,677 63,923
Other income 6,227   9,945   8,832 14,942
Interest expense 31,548   25,445   64,233 52,267
Income tax (benefit) expense 3,351   655   8,029 9,226
Income (loss) from continuing operations 19,273   14,177   100,220 96,644
Discontinued operations, net of tax 1,967   (397)   1,837 (899)
Net income 21,240 $ 80,817 13,780 $ 81,965 102,057 95,745
Total reportable segment operating revenues            
Segment Reporting [Line Items]            
Operating revenues  385,565   361,215   1,026,258 1,069,656
Total reportable segment operating revenues | Electric            
Segment Reporting [Line Items]            
Operating revenues  115,916   97,886   236,934 210,147
Purchased natural gas sold 0   0   0 0
Electric fuel and purchased power 38,674   34,891   84,741 78,639
Operation and maintenance 31,015   29,823   59,720 58,230
Depreciation and amortization 20,287   17,393   39,914 34,576
Taxes, other than income 5,368   4,648   10,888 9,463
Other income 1,842   2,726   2,293 3,718
Interest expense 11,094   7,614   23,005 15,501
Income tax (benefit) expense (3,343)   (4,254)   (8,255) (7,985)
Income (loss) from continuing operations 14,663   10,497   29,214 25,441
Discontinued operations, net of tax 0   0   0 0
Net income 14,663   10,497   29,214 25,441
Total reportable segment operating revenues | Natural gas distribution            
Segment Reporting [Line Items]            
Operating revenues  212,647   206,794   674,994 746,041
Purchased natural gas sold 93,538   96,057   332,929 413,214
Electric fuel and purchased power 0   0   0 0
Operation and maintenance 60,741   60,456   125,867 123,939
Depreciation and amortization 26,639   26,471   52,972 52,593
Taxes, other than income 16,806   16,935   43,258 47,563
Other income 3,865   5,095   6,135 8,396
Interest expense 15,945   13,745   32,231 28,621
Income tax (benefit) expense (3,215)   (4,170)   9,211 8,131
Income (loss) from continuing operations (3,842)   (7,356)   40,341 37,302
Discontinued operations, net of tax 0   0   0 0
Net income (3,842)   (7,356)   40,341 37,302
Total reportable segment operating revenues | Pipeline            
Segment Reporting [Line Items]            
Operating revenues  46,740   46,507   69,352 69,831
Purchased natural gas sold 0   0   0 0
Electric fuel and purchased power 0   0   0 0
Operation and maintenance 22,247   22,352   43,016 41,592
Depreciation and amortization 8,257   7,989   16,476 15,945
Taxes, other than income 3,773   3,583   7,531 6,897
Other income 242   1,616   (181) 1,923
Interest expense 3,801   3,135   6,903 6,256
Income tax (benefit) expense 4,042   4,337   8,744 9,464
Income (loss) from continuing operations 14,436   15,417   29,690 32,627
Discontinued operations, net of tax 0   0   0 0
Net income 14,436   15,417   29,690 32,627
Total reportable segment operating revenues | Other            
Segment Reporting [Line Items]            
Operating revenues  0   (1)   0 0
Purchased natural gas sold 0   0   0 0
Electric fuel and purchased power 0   0   0 0
Operation and maintenance 13   256   318 173
Depreciation and amortization 0   0   0 0
Taxes, other than income 0   0   0 0
Other income 278   508   585 905
Interest expense 708   951   2,094 1,889
Income tax (benefit) expense 5,867   4,742   (1,671) (384)
Income (loss) from continuing operations (5,984)   (4,381)   975 1,274
Discontinued operations, net of tax 1,967   (397)   1,837 (899)
Net income (4,017)   (4,778)   2,812 375
Intersegment eliminations            
Segment Reporting [Line Items]            
Operating revenues  (10,463)   (10,208)   (45,378) (43,995)
Purchased natural gas sold (9,900)   (9,751)   (44,320) (43,074)
Operation and maintenance (563)   (457)   (1,058) (921)
Other income (402)   (1,151)   (1,322) (2,260)
Interest expense (402)   (1,151)   (1,322) (2,260)
Intersegment eliminations | Electric            
Segment Reporting [Line Items]            
Operating revenues  (124)   (140)   (291) (318)
Purchased natural gas sold 0   0   0 0
Operation and maintenance (124)   (140)   (291) (318)
Other income 0   0   0 0
Interest expense 0   0   0 0
Intersegment eliminations | Natural gas distribution            
Segment Reporting [Line Items]            
Operating revenues  (86)   (92)   (175) (187)
Purchased natural gas sold (9,900)   (9,751)   (44,320) (43,074)
Operation and maintenance (86)   (92)   (175) (187)
Other income 0   0   0 0
Interest expense 0   0   0 0
Intersegment eliminations | Pipeline            
Segment Reporting [Line Items]            
Operating revenues  (10,052)   (9,796)   (44,512) (43,132)
Purchased natural gas sold 0   0   0 0
Operation and maintenance (152)   (45)   (192) (58)
Other income (76)   (90)   (191) (213)
Interest expense (402)   (1,151)   (1,322) (2,260)
Intersegment eliminations | Other            
Segment Reporting [Line Items]            
Operating revenues  (201)   (180)   (400) (358)
Purchased natural gas sold 0   0   0 0
Operation and maintenance (201)   (180)   (400) (358)
Other income (326)   (1,061)   (1,131) (2,047)
Interest expense $ 0   $ 0   $ 0 $ 0