v3.26.1
Schedule H; Line 4i - Schedule of Assets (Held at End of Year) (Details) - EBP 001
12 Months Ended
Dec. 31, 2025
USD ($)
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Plan Number 001
EBP, Plan Name EAGLE MATERIALS INC. RETIREMENT PLAN
Current Value, Total $ 328,614,300
Investment, Identifier [Axis]: Brokerage Link Participant Directed Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Brokerage Link [Member]
Party-in-interest true
Current Value $ 3,594,939
Investment, Identifier [Axis]: Eagle Materials Inc. Common Stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Eagle Materials Inc. [Member]
Party-in-interest true
Current Value $ 11,532,928
Investment, Identifier [Axis]: Fidelity Core Plus Bond Fund Class I  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Fidelity [Member]
Current Value $ 2,401,883
Investment, Identifier [Axis]: Fidelity Government MMKT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Fidelity [Member]
Party-in-interest true
Current Value $ 34,761
Investment, Identifier [Axis]: Great Grey Trust Euro-Pacific Growth Trust Class CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Great Grey Trust [Member]
Current Value $ 4,750,189
Investment, Identifier [Axis]: Harbor Capital Appreciation Fund CIT Class R  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Harbor Capital [Member]
Current Value $ 15,100,429
Investment, Identifier [Axis]: MFS Large Cap Value CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] MFS [Member]
Current Value $ 5,640,095
Investment, Identifier [Axis]: MFS Mid Cap Growth Fund CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] MFS [Member]
Current Value $ 8,050,136
Investment, Identifier [Axis]: MFS Mid Cap Value Fund CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] MFS [Member]
Current Value $ 7,522,215
Investment, Identifier [Axis]: NY Life Guaranteed Investment Contract at 3.25%  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] NY Life [Member]
Rate of Interest 3.25%
Current Value $ 4,985,334
Investment, Identifier [Axis]: Northern Trust ACWI Ex-US Investable Market Index CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Northern Trust [Member]
Current Value $ 2,274,145
Investment, Identifier [Axis]: Northern Trust Aggregate Bond Index Fund Non-Lending CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Northern Trust [Member]
Current Value $ 3,474,223
Investment, Identifier [Axis]: Northern Trust Extended Equity Market Index Fund-DC Non-Lending CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Northern Trust [Member]
Current Value $ 5,287,722
Investment, Identifier [Axis]: Northern Trust S&P 500 Index Fund-DC Non-Lending CT  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Northern Trust [Member]
Current Value $ 39,427,859
Investment, Identifier [Axis]: Notes receivable with interest rates from 5.25% to 10.50%  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value $ 7,387,687
Investment, Identifier [Axis]: Notes receivable with interest rates from 5.25% to 10.50% | Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Rate of Interest 5.25%
Investment, Identifier [Axis]: Notes receivable with interest rates from 5.25% to 10.50% | Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Rate of Interest 10.50%
Investment, Identifier [Axis]: Participants Notes receivable with interest rates from 5.25% to 10.50%  
EBP, Schedule of Asset Held for Investment [Line Items]  
Party-in-interest true
Investment, Identifier [Axis]: Principal Principal SmallCap Growth I R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Principal [Member]
Current Value $ 2,331,984
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2020 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 11,172,548
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2025 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 11,466,299
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2030 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 46,802,048
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2035 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 16,662,636
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2040 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 50,888,572
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2045 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 13,647,435
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2050 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 20,763,083
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2055 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 9,329,425
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2060 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 10,717,562
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2065 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 3,835,044
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement 2070 Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 1,485,486
Investment, Identifier [Axis]: Vanguard Vanguard Target Retirement Income Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Vanguard [Member]
Current Value $ 6,430,494
Investment, Identifier [Axis]: Wells Fargo Special SmallCap Value Fund R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] Wells Fargo [Member]
Current Value $ 1,617,139