XML 72 R52.htm IDEA: XBRL DOCUMENT v3.20.4
Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disaggregation of Revenue [Line Items]      
Total Operating Revenues $ 890,107 $ 919,503 $ 916,447
Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues from Contracts with Customers 883,171 918,471 916,886
Operating Segments | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 446,088 459,048 450,198
Electric Segment - Alternative Revenue Program Revenues 6,936 1,032 (439)
Operating Segments | Manufacturing      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 238,770 277,204 268,409
Operating Segments | Plastics      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 205,249 183,251 197,840
Operating Segments | Retail: Residential | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 127,260 131,988 125,045
Operating Segments | Retail: Commercial and Industrial | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 254,951 267,125 256,331
Operating Segments | Retail: Other | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 7,311 7,365 6,875
Operating Segments | Total Retail | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 389,522 406,478 388,251
Operating Segments | Transmission | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 44,001 40,542 46,947
Operating Segments | Wholesale | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 4,857 5,007 7,735
Operating Segments | Other | Electric      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 7,708 7,021 7,265
Operating Segments | Metal Parts and Tooling | Manufacturing      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 199,463 236,032 223,765
Operating Segments | Plastic Products and Tooling | Manufacturing      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues 34,055 35,173 35,836
Operating Segments | Other | Manufacturing      
Disaggregation of Revenue [Line Items]      
Total Operating Revenues $ 5,252 $ 5,999 $ 8,808