XML 107 R77.htm IDEA: XBRL DOCUMENT
v3.22.4

Regulatory liabilities (Details 2) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2022 | Dec. 31, 2021
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities due within one year | $ 26,440 | $ 16,303
Regulatory liabilities | 448,454 | 428,790
Total regulatory liabilities | 474,894 | 445,093
Net Regulatory Position | $ 19,857 | 31,449
Electric fuel and purchased power deferral |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Regulatory liabilities due within one year | $ 4,929 | 0
Conservation programs |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Regulatory liabilities due within one year | $ 4,126 | 12
Taxes refundable to customers |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities due within one year | 3,937 | 3,841
Regulatory liabilities | $ 203,222 | 215,421
Taxes refundable to customers | Minimum |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Taxes refundable to customers | Maximum |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Over plant lives |
Refundable Fuel and Electric Costs |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Regulatory liabilities due within one year | $ 3,253 | 713
Natural gas costs refundable through rate adjustments |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Regulatory liabilities due within one year | $ 955 | 6,700
Other regulatory liabilities |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities due within one year | 9,240 | 5,037
Regulatory liabilities | $ 1,587 | 9,168
Other regulatory liabilities | Minimum |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 1 year |
Other regulatory liabilities | Maximum |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 15 years |
Plant removal and decommissioning costs |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Over plant lives |
Regulatory liabilities | $ 208,650 | 168,152
Cost recovery mechanisms |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 19 years |
Regulatory liabilities | $ 14,025 | 2,919
Accumulated deferred investment tax credit |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | Up to 19 years |
Regulatory liabilities | $ 13,594 | 12,696
Pension and postretirement benefits |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liability, refund period | ** |
Regulatory liabilities | $ 7,376 | $ 20,434

X
- Definition regulatory liability, refund period + References No definition available. + Details
Name: | mdu_RegulatoryLiabilityRefundPeriod
Namespace Prefix: | mdu_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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 https://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_NetRegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 https://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
Name: | us-gaap_RegulatoryLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RegulatoryLiabilitiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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 https://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394 + Details
Name: | us-gaap_RegulatoryLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent 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 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.24) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_RegulatoryLiabilityNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=mdu_ElectricFuelAndPurchasedPowerDeferralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_RenewableEnergyProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=mdu_RefundableFuelAndElectricCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=mdu_LiabilitiesRefundableGasCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_OtherRegulatoryAssetsLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_RemovalCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=mdu_RegulatoryClauseRevenuesOverRecoveredMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=mdu_AccumulatedDefferedITCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryLiabilityAxis=us-gaap_PensionAndOtherPostretirementPlansCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |