v3.26.1
Revenue (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Total Operating Revenues $ 334,383 $ 333,043 $ 681,409 $ 670,396
Total Operating Revenues from Contracts with Customers 334,737 332,433 677,597 669,768
Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 121,320 128,731 287,188 278,451
Electric Segment - ARP Revenues (354) 610 3,812 628
Manufacturing        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 88,461 78,726 178,021 160,412
Plastics        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 124,602 125,586 216,200 231,533
Total Retail | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 106,111 110,130 255,347 243,502
Retail: Residential | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 28,907 29,586 74,962 72,846
Retail: Commercial and Industrial | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 75,208 78,699 176,153 166,585
Retail: Other | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 1,996 1,845 4,232 4,071
Transmission | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 11,101 13,232 24,551 25,363
Wholesale | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 883 3,261 2,386 6,039
Other | Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 3,225 2,108 4,904 3,547
Metal Parts and Tooling | Manufacturing        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 77,546 69,348 155,190 140,219
Plastic Products and Tooling | Manufacturing        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 8,809 7,587 18,650 16,545
Scrap Metal | Manufacturing        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues $ 2,106 $ 1,791 $ 4,181 $ 3,648