Revenue: Disaggregation of Revenue (Details) - USD ($) $ in Thousands |
3 Months Ended |
6 Months Ended |
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
$ 368,423
|
$ 324,193
|
$ 998,640
|
$ 854,402
|
Total revenues |
372,572
|
326,914
|
1,006,004
|
863,964
|
Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
6,714
|
6,930
|
13,690
|
13,494
|
Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
361,709
|
317,263
|
984,950
|
840,908
|
Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
4,149
|
2,721
|
7,364
|
9,562
|
Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
309,029
|
269,328
|
856,110
|
722,779
|
Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
31,540
|
30,654
|
79,381
|
74,623
|
Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
4,442
|
4,712
|
14,605
|
12,119
|
Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
7,353
|
1,981
|
12,198
|
4,347
|
Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
16,059
|
17,518
|
36,346
|
40,534
|
Inter-company Revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(37,703)
|
(38,542)
|
(77,551)
|
(77,184)
|
Total revenues |
(38,188)
|
(38,934)
|
(78,518)
|
(77,967)
|
Inter-company Revenues | Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(7,140)
|
(7,916)
|
(14,247)
|
(15,755)
|
Inter-company Revenues | Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(30,563)
|
(30,626)
|
(63,304)
|
(61,429)
|
Inter-company Revenues | Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
(485)
|
(392)
|
(967)
|
(783)
|
Inter-company Revenues | Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(7,140)
|
(7,916)
|
(14,247)
|
(15,755)
|
Inter-company Revenues | Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(109)
|
(138)
|
(219)
|
(277)
|
Inter-company Revenues | Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(23,480)
|
(24,476)
|
(47,931)
|
(48,088)
|
Inter-company Revenues | Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(1,675)
|
(1,580)
|
(4,559)
|
(4,219)
|
Inter-company Revenues | Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
(5,299)
|
(4,432)
|
(10,595)
|
(8,845)
|
Electric Utilities |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
182,654
|
161,573
|
409,925
|
335,489
|
Total revenues |
184,933
|
163,200
|
412,341
|
337,339
|
Electric Utilities | Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Electric Utilities | Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
182,654
|
161,573
|
409,925
|
335,489
|
Electric Utilities | Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
2,279
|
1,627
|
2,416
|
1,850
|
Electric Utilities | Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
158,470
|
141,804
|
356,970
|
290,444
|
Electric Utilities | Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Electric Utilities | Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
3,010
|
3,470
|
8,932
|
9,022
|
Electric Utilities | Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
8,941
|
3,538
|
16,597
|
8,405
|
Electric Utilities | Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
12,233
|
12,761
|
27,426
|
27,618
|
Gas Utilities |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
184,706
|
160,598
|
584,725
|
515,663
|
Total revenues |
186,050
|
161,110
|
588,569
|
521,883
|
Gas Utilities | Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Gas Utilities | Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
184,706
|
160,598
|
584,725
|
515,663
|
Gas Utilities | Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
1,344
|
512
|
3,844
|
6,220
|
Gas Utilities | Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
143,845
|
120,594
|
485,450
|
418,841
|
Gas Utilities | Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
31,649
|
30,792
|
79,600
|
74,900
|
Gas Utilities | Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Gas Utilities | Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
87
|
23
|
160
|
161
|
Gas Utilities | Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
9,125
|
9,189
|
19,515
|
21,761
|
Power Generation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
24,912
|
25,718
|
53,604
|
51,185
|
Total revenues |
25,348
|
26,122
|
54,511
|
52,088
|
Power Generation | Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Power Generation | Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
24,912
|
25,718
|
53,604
|
51,185
|
Power Generation | Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
436
|
404
|
907
|
903
|
Power Generation | Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Power Generation | Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Power Generation | Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
24,912
|
25,718
|
53,604
|
51,185
|
Power Generation | Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Power Generation | Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Mining |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
13,854
|
14,846
|
27,937
|
29,249
|
Total revenues |
14,429
|
15,416
|
29,101
|
30,621
|
Mining | Services transferred at a point in time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
13,854
|
14,846
|
27,937
|
29,249
|
Mining | Services transferred over time |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Mining | Other revenues |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Total revenues |
575
|
570
|
1,164
|
1,372
|
Mining | Retail - Electric , Natural Gas and Coal |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
13,854
|
14,846
|
27,937
|
29,249
|
Mining | Transportation |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Mining | Wholesale |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Mining | Market - off-system sales |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
0
|
0
|
0
|
0
|
Mining | Transmission/Other |
|
|
|
|
Disaggregation of Revenue [Line Items] |
|
|
|
|
Revenue from contracts with customers |
$ 0
|
$ 0
|
$ 0
|
$ 0
|