REVENUE (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2019 |
Jun. 30, 2020 |
Jun. 30, 2019 |
Dec. 31, 2019 |
|
| Unbilled Receivables, Current | $ 49,000 | $ 49,000 | $ 109,700 | ||
| Regulated Operating Revenue, Gas | 270,909 | $ 287,979 | 789,854 | $ 949,927 | |
| Regulated Operating Revenue, Other | 2,378 | 11,601 | |||
| Regulated Operating Revenue, Other Credit | 2,581 | 1,633 | |||
| Regulated Operating Revenue | 273,287 | 290,560 | 801,455 | 951,560 | |
| Natural gas sales to customers [Member] | |||||
| Regulated Operating Revenue, Gas | 243,308 | 258,560 | 724,026 | 880,052 | |
| Transportation revenues [Member] | |||||
| Regulated Operating Revenue, Gas | 24,481 | 23,991 | 58,238 | 59,019 | |
| Miscellaneous revenues [Member] | |||||
| Regulated Operating Revenue, Gas | 3,120 | 5,428 | 7,590 | 10,856 | |
| Other revenues - natural gas sales related [Member] | |||||
| Other revenues - natural gas sales related | (3) | 207 | 6,544 | (2,737) | |
| Other revenues [Member] | |||||
| Regulated Operating Revenue, Other | $ 2,381 | $ 2,374 | $ 5,057 | $ 4,370 | |