Entity tax identification number Entity Tax Identification Number Rollover EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Maximum Maximum [Member] Participant forfeitures EBP, Forfeited Nonvested Account, Decrease from Administrative Expense Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Notes receivable, maximum term EBP, Note Receivable From Participant, General Loan, Maximum Borrowing Term EBP, Note Receivable From Participant, General Loan, Maximum Borrowing Term EBP, Description of Plan [Table] EBP, Description of Plan [Table] Mutual funds Mutual Funds Mutual Fund [Member] Guaranteed Investment Contract EBP, Traditional Guaranteed Investment Contract [Member] Employer Matching Contribution EBP, Employer Matching Contribution [Member] EBP, Employer Matching Contribution Participant compensation, hours of service EBP, Requisite Service Period, Number Of Hours EBP, Requisite Service Period, Number Of Hours EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] Self-directed brokerage account Schwab Funds EBP, Self-Directed Brokerage Account [Member] Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Notes receivable, maximum borrowing amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount FAIR VALUE MEASUREMENTS EBP, Investment, Fair Value and NAV [Text Block] Notes receivable, minimum borrowing amount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount Vesting percentage EBP, Employer Contribution Vesting Percentage EBP, Employer Contribution Vesting Percentage EBP, Fully Benefit-Responsive Investment Contract [Abstract] Participant-directed investments, at fair value Investments EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Level 1 Fair Value, Inputs, Level 1 [Member] GROUP ANNUITY CONTRACT WITH PRINCIPAL LIFE INSURANCE COMPANY EBP, Fully Benefit-Responsive Investment Contract [Text Block] Automatic annual deferral rate increase EBP, Participant Contribution, Automatic, Annual Increase Deferral Rate EBP, Participant Contribution, Automatic, Annual Increase Deferral Rate Part-time Employee Part-time Employee [Member] Part-time Employee EBP, Investment, Fair Value and NAV [Abstract] 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] Distributions to Participants EBP, Payment to Participant [Policy Text Block] 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] Crediting rate EBP, Investment, Interest Rate EBP, Description of Plan and Accounting Change [Abstract] Categorization of the Plan's Investments Measured at Fair Value on a Recurring Basis EBP, Investment, Fair Value and NAV [Table Text Block] Investments [Domain] Investments [Domain] EBP, Schedule of Delinquent Participant Contribution [Abstract] Discretionary Contribution EBP, Discretionary Contribution [Member] EBP, Discretionary Contribution Use of Estimates EBP, Use of Estimate [Policy Text Block] Pooled Separate Accounts Pooled Separate Accounts EBP, Pooled Separate Account [Member] Form 5500, Schedule H, Part IV, Line 4i - Schedule of Assets (Held at End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Employer EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash EBP, Schedule of Delinquent Participant Contribution [Line Items] EBP, Schedule of Delinquent Participant Contribution [Line Items] 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 EBP, Employment Status [Domain] EBP, Employment Status [Domain] EBP, Employment Status [Domain] Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Participant EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net realized and unrealized appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] EBP, Employer Contribution, Type [Domain] EBP, Employer Contribution, Type [Domain] EBP, Employer Contribution, Type [Domain] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] PLAN DESCRIPTION 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] Contributions EBP, Contribution [Policy Text Block] Principal Life Insurance Company Fixed Income Funds [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 EBP 004 EBP 004 [Member] EBP 004 Investment income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Total assets held for investment purposes EBP, Asset Held for Investment Risks and Uncertainties EBP, Risk and Uncertainty [Policy Text Block] Document Information [Line Items] Document Information [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Table] EBP, Risk and Uncertainty [Table] Participant compensation matched percentage EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, Statement of Change in Net Asset Available for Benefit [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Vesting period EBP, Employer Contribution Vesting Service Period EBP, Employer Contribution Vesting Service Period EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Tax Status [Table] EBP, Tax Status [Table] Increase (decrease) in net assets available for benefits EBP, Change in Net Asset Available for Benefit, Increase (Decrease) 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] Maximum deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Benefits paid to participants EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Dividends EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment Current Value EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Late remittance EBP, Schedule of Delinquent Participant Contribution, Transferred Late to Plan Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] United Fire stock fund United Fire Group, Inc EBP, Employer, Common Stock Fund [Member] Participant Loans EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Participant-Directed Investments / Investment Income EBP, Investment [Policy Text Block] Document Type Document Type PLAN TERMINATION EBP, Plan Termination [Text Block] Entity Central Index Key Entity Central Index Key Participant Loans, Interest Rate EBP, Asset Held for Investment, Participant Loan, Interest Rate Investments: EBP, Investment, Fair and Contract Value [Abstract] Common collective trusts Common Collective Trusts Common Collective Trust [Member] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] EBP, Risk and Uncertainty [Abstract] Deductions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] 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 PARTICIPANT CONTRIBUTIONS TRANSFERRED LATE TO PLAN EBP, Delinquent Participant Contributions [Text Block] EBP, Delinquent Participant Contributions EBP, Schedule of Delinquent Participant Contribution [Table] EBP, Schedule of Delinquent Participant Contribution [Table] Surrender charge EBP, Investment, Surrender Charge EBP, Investment, Surrender Charge Subsequent Events EBP, Subsequent Event [Policy Text Block] FEDERAL INCOME TAX STATUS EBP, Tax Status [Text Block] Other expenses EBP, Change In Net Asset Available for Benefit, Decrease From Other Expense EBP, Change In Net Asset Available for Benefit, Decrease From Other Expense Notes receivable, minimum term EBP, Note Receivable From Participant, General Loan, Minimum Borrowing Term EBP, Note Receivable From Participant, General Loan, Minimum Borrowing Term Notes receivable, maximum borrowing to total account, percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage EBP, Employer Contribution, Type [Axis] EBP, Employer Contribution, Type [Axis] EBP, Employer Contribution, Type EBP, Employment Status [Axis] EBP, Employment Status [Axis] EBP, Employment Status Document Information [Table] Document Information [Table] Note Receivable from Participant EBP, Note Receivable from Participant [Policy Text Block] Net investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Full-time Employee Full-time Employee [Member] Full-time Employee 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] Net Assets Available for Benefits Balance, beginning of year Balance, end of year 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] Participant-directed investments, at contract value Contract value EBP, Investment, Excluding Plan Interest in Master Trust, Contract Value Matching percentage EBP, Employer Contribution, Matching Percentage Lost earnings EBP, Schedule of Delinquent Participant Contribution, Transferred Late to Plan, Lost Earnings EBP, Schedule of Delinquent Participant Contribution, Transferred Late to Plan, Lost Earnings 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]