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v3.21.1

Regulatory assets and liabilities (Details) - USD ($) $ in Thousands | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2021 | Feb. 28, 2021 | Dec. 31, 2020 | Mar. 31, 2020
Regulatory Assets and Liabilities |  |  |  |
Regulatory Assets, Current | $ 98,452 |  | $ 68,527 | $ 55,206
Regulatory Assets, Noncurrent | 379,917 |  | 379,381 | 348,189
Total regulatory assets | 478,369 |  | 447,908 | 403,395
Regulatory Liability, Current | 34,266 |  | 31,450 | 60,072
Regulatory Liability, Noncurrent | 429,060 |  | 428,075 | 443,205
Total regulatory liabilities | 463,326 |  | 459,525 | 503,277
Net regulatory position | 15,043 |  | (11,617) | (99,882)
Regulatory assets not earning a rate of return | $ 361,400 |  | 332,500 | 285,800
Natural gas costs refundable through rate adjustments |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Regulatory Liability, Current | $ 16,344 |  | 18,565 | 32,181
Taxes refundable to customers |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Regulatory Liability, Current | 3,092 |  | 3,557 | 4,002
Regulatory Liability, Noncurrent | $ 224,795 |  | 227,850 | 240,148
Taxes refundable to customers | Minimum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Taxes refundable to customers | Maximum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Over plant lives |  |  |
Electric fuel and purchased power deferral |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Regulatory Liability, Current | $ 2,001 |  | 3,667 | 7,188
Plant removal and decommissioning costs |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Over plant lives |  |  |
Regulatory Liability, Noncurrent | $ 169,430 |  | 167,171 | 174,120
Pension and postretirement benefits |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | ** |  |  |
Regulatory Liability, Noncurrent | $ 16,965 |  | 16,989 | 18,040
Other Regulatory Liabilities |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Regulatory Liability, Current | 12,829 |  | 5,661 | 16,701
Regulatory Liability, Noncurrent | $ 17,870 |  | 16,065 | 10,897
Other Regulatory Liabilities | Minimum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Other Regulatory Liabilities | Maximum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 21 years |  |  |
Natural gas costs recoverable through rate adjustments |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Regulatory Assets, Current | $ 76,782 |  | 42,481 | 39,805
Regulatory Assets, Noncurrent | $ 15,158 |  | 21,539 | 33,027
Natural gas costs recoverable through rate adjustments | Minimum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Natural gas costs recoverable through rate adjustments | Maximum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 3 years |  |  |
Cost recovery mechanisms |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Regulatory Assets, Current | $ 7,130 |  | 10,645 | 6,686
Regulatory Assets, Noncurrent | $ 15,508 |  | 16,245 | 11,891
Cost recovery mechanisms | Minimum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Cost recovery mechanisms | Maximum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 10 years |  |  |
Conservation programs |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Regulatory Assets, Current | $ 6,679 |  | 7,117 | 6,303
Pension and postretirement benefits |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | ** |  |  |
Regulatory Assets, Noncurrent | $ 155,924 |  | 155,942 | 157,051
Plant removal and decommissioning costs |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | - |  |  |
Regulatory Assets, Noncurrent | $ 73,498 |  | 65,919 | 41,080
Plant costs/asset retirement obligations |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Over plant lives |  |  |
Regulatory Assets, Noncurrent | $ 72,250 |  | 71,740 | 67,475
Manufactured gas plant site remediation |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | - |  |  |
Regulatory Assets, Noncurrent | $ 26,002 |  | 26,429 | 15,699
Taxes refundable to customers |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Over plant lives |  |  |
Regulatory Assets, Noncurrent | $ 10,800 |  | 10,785 | 11,082
Long-term debt refinancing costs |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 39 years |  |  |
Regulatory Assets, Noncurrent | $ 4,268 |  | 4,426 | 4,133
Other Regulatory Liabilities |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Regulatory Assets, Current | 7,861 |  | 8,284 | 2,412
Regulatory Assets, Noncurrent | $ 6,509 |  | $ 6,356 | $ 6,751
Other Regulatory Liabilities | Minimum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 1 year |  |  |
Other Regulatory Liabilities | Maximum [Member] |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Estimated Recovery or Refund Period as of March 31, 2021 | Up to 18 years |  |  |
Increased Gas Costs |  |  |  |
Regulatory Assets and Liabilities |  |  |  |
Total regulatory assets |  | $ 44,000 |  |

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- Definition The net amount of all regulatory assets less all regulatory liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
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- Definition Describes the continual or periodic assessment of the probability of future recovery of regulatory assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 40 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499898&loc=d3e44174-110380 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557228&loc=d3e43603-110378 + Details
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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
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- Definition The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 405 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
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- Definition The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 405 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
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- Definition Remaining balance of regulatory assets for which no return on investment during recovery is provided. In some cases, a regulator may permit an enterprise to include a cost that would be charged to expense by an unregulated enterprise as an allowable cost over a period of time by amortizing that cost for rate-making purposes, but the regulator does not include the unrecovered amount in the rate base. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 55 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121594574&loc=d3e44360-110383 + Details
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