Entity tax identification number Entity Tax Identification Number Participant rollovers EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Maximum Maximum [Member] Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Mutual funds Mutual Fund [Member] Automatic deferral rate, annual increase EBP, Participant Contribution, Automatic, Annual Increase Deferral Rate Annual increase in percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) until the contribution reaches maximum threshold. Selling price EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] Vesting percentage EBP, Employer Contribution Vesting Percentage Company contribution and/ or investment earning percentage vesting to the participant in Company Matching Contributions, Fixed Rate Contributions, Discretionary Profit-Sharing Contributions, Qualified Non-Elective Contributions, and Disability Contributions, upon completion of minimum service period or attainment of maximum vesting age Pretax, maximum annual compensation to total compensation, percentage EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Maximum borrowing, amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Fair Value Measurements EBP, Investment, Fair Value and NAV [Text Block] Minimum borrowing, amount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount EBP, Fully Benefit-Responsive Investment Contract [Abstract] Investments, at fair value Total investments EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Maximum approved loans EBP, Maximum Number Of Outstanding Loans EBP, Maximum Number Of Outstanding Loans Level 1 Fair Value, Inputs, Level 1 [Member] Investment Contract with Insurance Company EBP, Fully Benefit-Responsive Investment Contract [Text Block] EBP, Investment, Fair Value and NAV [Abstract] Incremental participant allocated contribution percentage EBP, Participant Allocated Contribution, Incremental Percentage EBP, Participant Allocated Contribution, Incremental Percentage EBP, Employer Contribution, Type [Axis] EBP, Employer Contribution, Type [Axis] EBP, Employer Contribution, Type Total assets EBP, Asset Assets: EBP, Asset [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] Additions: EBP, Change in Net Asset Available for Benefit, Increase [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Benefit Payments EBP, Payment to Participant [Policy Text Block] Assets transferred into plan EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan Common stock exchange ratio EBP, Separation Agreement, Common Stock Exchange Rate EBP, Separation Agreement, Common Stock Exchange Rate Amendment Flag Amendment Flag Basis of Accounting EBP, Basis of Accounting [Policy Text Block] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Profit sharing and retirement contributions EBP, Profit Sharing And Retirement Contributions, Amount EBP, Profit Sharing And Retirement Contributions, Amount Investment, number of shares (in shares) EBP, Investment, Number of Shares EBP, Description of Plan and Accounting Change [Abstract] Receivables: EBP, Receivable [Abstract] Notes Receivable from Participants Notes Receivable From Participants [Member] Notes Receivable From Participants Summary of Plan Assets Measured at Fair Value EBP, Investment, Fair Value and NAV [Table Text Block] Common stock Common Stock [Member] Investments [Domain] Investments [Domain] EBP, Nonemployer, Common Stock EBP, Nonemployer, Common Stock [Member] Use of Estimates EBP, Use of Estimate [Policy Text Block] Schedule H, Line 4i – Schedule of Assets (Held At End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Employers EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash Investments Representing more than 10% of Net Plan Assets EBP, Risk and Uncertainty [Table Text Block] Vesting period EBP, Employer Contribution Vesting Service Period Minimum Vesting service period for company contribution and/ or investment earning to the participant in Company Matching Contributions, Fixed Rate Contributions, Discretionary Profit-Sharing Contributions, Qualified Non-Elective Contributions, and Disability Contributions. Minimum Minimum [Member] Investment Type [Axis] Investment Type [Axis] Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Participants EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net appreciation in fair values of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Interest and dividends EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] Description of the Plan EBP, Description of Plan [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] Related and Nonrelated Parties [Domain] Related and Nonrelated Parties [Domain] Contributions EBP, Contribution [Policy Text Block] Common stock EBP, Employer, Common Stock [Member] EBP, Schedule of Asset Held for Investment [Abstract] EBP, Accounting Policy [Table] EBP, Accounting Policy [Table] Total additions EBP, Change in Net Asset Available for Benefit, Increase Minimum annual hours of required service for vesting purposes EBP, Service Vesting, Minimum Hours Of Required Service EBP, Service Vesting, Minimum Hours Of Required Service Investment income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment management fees EBP, Investment Management Fees EBP, Investment Management Fees Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense EBP, Asset Held for Investment EBP, Asset Held for Investment EBP 001 EBP 001 [Member] EBP 001 Risks and Uncertainties EBP, Risk and Uncertainty [Policy Text Block] Document Information [Line Items] Document Information [Line Items] Fixed Rate Contribution EBP, Fixed Rate Contribution [Member] EBP, Fixed Rate Contribution Percentage of common stock sold by former parent EBP, Percentage Of Common Stock Sold By Former Parent EBP, Percentage Of Common Stock Sold By Former Parent EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Tax Status [Table] EBP, Tax Status [Table] Net increase in net assets available for benefits after Plan transfers EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Related-Party and Exempt Party-In-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Total receivables EBP, Receivable Counterparty Name [Domain] Counterparty Name [Domain] Employer contributions EBP, Employer Contribution, Receivable Automatic deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Investments - participant-directed: EBP, Investment, Fair Value [Abstract] Distributions - participants EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Total investments EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Related party Related Party [Member] Related and Nonrelated Parties [Axis] Related and Nonrelated Parties [Axis] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] Cash (non-interest bearing) EBP, Noninterest-Bearing Cash Administrative Expenses and Revenue Sharing EBP, Expense [Policy Text Block] Participant loan, current value EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Investment Valuation and Income Recognition EBP, Investment [Policy Text Block] MDU Resources MDU Resources [Member] MDU Resources Distribution period EBP, Employer Distribution Period EBP, Employer Distribution Period Participant contributions EBP, Participant Contribution, Receivable Fair Value, Inputs, Level 1, Level 2, and Level 3 Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Document Type Document Type General loan, borrowing term EBP, Note Receivable From Participant, General Loan, Maximum Borrowing Term EBP, Note Receivable From Participant, General Loan, Maximum Borrowing Term Entity Central Index Key Entity Central Index Key Participant loan, interest rate EBP, Asset Held for Investment, Participant Loan, Interest Rate Common/collective trusts Common Collective Trust [Member] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Deductions: EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Forfeited nonvested account, decrease from employer contribution EBP, Forfeited Nonvested Account, Decrease from Employer Contribution Notes receivable from participants EBP, Note Receivable from Participant Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Amount EBP, Risk and Uncertainty, Concentration of Investment at Fair Value to Net Assets, Amount Cost of asset EBP, Investment Acquired, Excluding Plan Interest in Master Trust, Cost Percent of net assets EBP, Risk and Uncertainty, Concentration of Investment at Fair Value to Net Assets, Percentage Realized gain (loss) EBP, Investment Sold, Excluding Plan Interest in Master Trust, Realized Gain (Loss) EBP, Investment Sold, Excluding Plan Interest in Master Trust, Realized Gain (Loss) Profit sharing and retirement contributions included in Employer contributions receivable EBP, Profit Sharing And Retirement Contributions Included in Employer Contributions Receivable, Amount EBP, Profit Sharing And Retirement Contributions Included in Employer Contributions Receivable, Amount Net increase in net assets available for benefits prior to Plan transfers EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Before Plan Transfers EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Before Plan Transfers Subsequent Events EBP, Subsequent Event [Policy Text Block] Federal Income Taxes EBP, Tax Status [Text Block] Maximum borrowing, to total account, percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Document Information [Table] Document Information [Table] Counterparty Name [Axis] Counterparty Name [Axis] Notes Receivable from Participants EBP, Note Receivable from Participant [Policy Text Block] Primary residence, borrowing term EBP, Note Receivable From Participant, Account, Primary Residence, Maximum Borrowing Term EBP, Note Receivable From Participant, Account, Primary Residence, Maximum Borrowing Term Total investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Employer Contribution, Type [Domain] EBP, Employer Contribution, Type [Domain] EBP, Employer Contribution, Type [Domain] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Level 3 Fair Value, Inputs, Level 3 [Member] Investment benchmark threshold (as a percentage) EBP, Risk and Uncertainty, Concentration of Investment, Benchmark Threshold Percentage Net assets available for benefits Net assets available for benefits at beginning of period Net assets available for benefits at end of period EBP, Net Asset Available for Benefit Total investments EBP, Investment, Excluding Plan Interest in Master Trust, Fair and Contract Value Entity [Domain] Entity [Domain] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Investments, at contract value EBP, Investment, Excluding Plan Interest in Master Trust, Contract Value Forfeited nonvested account EBP, Forfeited Nonvested Account NAV Fair Value Measured at Net Asset Value Per Share [Member] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items] Return of investment fees EBP, Revenue Sharing, Return Of Investment Fees EBP, Revenue Sharing, Return Of Investment Fees