Ratio of total debt to total capitalization for the current period ended.

No definition available.

Name:	mdu_DebtCovenantTotalDebtToTotalCapitalizationRatio
Namespace Prefix:	mdu_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of shares retained in Knife River

+ References

No definition available.

+ Details

Name:	mdu_DisposalGroupIncludingDiscontinuedOperationRetainedSharesOwnershipPercentage
Namespace Prefix:	mdu_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow for a borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfShortTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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_ShortTermDebtLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsDisposedOfByMeansOtherThanSaleSpinoffMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=mdu_KnifeRiverCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mdu_MDUResourcesGroupInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mdu_TermLoanAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=mdu_TermLoanAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mdu_CascadeNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mdu_IntermountainGasCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mdu_CentennialEnergyHoldingsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Short-Term Debt (Details)			1 Months Ended			12 Months Ended
Debt - Short-Term Debt (Details)	Dec. 05, 2023 USD ($)	Nov. 10, 2023 USD ($)	May 31, 2023 USD ($)	Apr. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 06, 2023 USD ($)	May 01, 2023 USD ($)	Jan. 20, 2023 USD ($)	Dec. 19, 2022 USD ($)	Mar. 18, 2022 USD ($)
Short-term Debt [Line Items]
Short-term borrowings						$ 95,000,000	$ 38,500,000
Repayment of short-term borrowings						$ 460,901,000	$ 0	$ 100,000,000
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| Knife River Corporation
Short-term Debt [Line Items]
Retained ownership percentage			0.10
MDU Resources Group, Inc. \| Term Loan Agreement
Short-term Debt [Line Items]
Ratio of total debt to total capitalization						65
MDU Resources Group, Inc. \| Revolving Credit Facility
Short-term Debt [Line Items]
Short-term borrowings			$ 150,000,000			$ 0
Ratio of total debt to total capitalization			0.65
Term Loan Agreement \| Cascade Natural Gas
Short-term Debt [Line Items]
Short-term borrowings											$ 150,000,000
Repayment of short-term borrowings	$ 100,000,000
Term Loan Agreement \| Intermountain Gas Company
Short-term Debt [Line Items]
Short-term borrowings											$ 125,000,000
Repayment of short-term borrowings			$ 30,000,000	$ 30,000,000	$ 20,000,000
Term Loan Agreement \| Centennial Energy Holdings, Inc.
Short-term Debt [Line Items]
Short-term borrowings												$ 135,000,000	$ 100,000,000
Term Loan Agreement \| MDU Resources Group, Inc.
Short-term Debt [Line Items]
Short-term borrowings									$ 310,000,000	$ 75,000,000
Repayment of short-term borrowings		$ 293,200,000