Schedule of Assets (Details) - Mayville Engineering Company, Inc. 401(k) Plan $ in Thousands	12 Months Ended
Dec. 31, 2025 USD ($)
Schedule of Assets
Entity tax identification number	39-0944729
Plan number	003
Current Value	$ 184,242
Investment, Identifier [Axis]: Capital Research and Mgmt. Co., American Funds Capital World Growth and Income R6
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:CapitalResearchAndMgmt.Co.Member
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,729
Investment, Identifier [Axis]: Capital Research and Mgmt. Co., American Funds EuroPacific Growth R6
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:CapitalResearchAndMgmt.Co.Member
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,607
Investment, Identifier [Axis]: Fidelity, 500 Index
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:FidelityMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 14,398
Investment, Identifier [Axis]: Fidelity, Advisor Stock Selector Mid Cap
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:FidelityMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 3,265
Investment, Identifier [Axis]: J.P. Morgan, Mid Cap Value R6 Fund
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:J.p.MorganMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 1,681
Investment, Identifier [Axis]: Janus Henderson, Forty N
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:JanusHendersonMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 10,840
Investment, Identifier [Axis]: Janus Henderson, Research N
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:JanusHendersonMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 5,340
Investment, Identifier [Axis]: MEC, Common Stock, No Par Value
Schedule of Assets
EBP, Asset Held for Investment, Party-in-Interest [true false]	true
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:MecMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Corporate common stock
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 44,339
Investment, Identifier [Axis]: MFS, Value R3
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:MfsMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,901
Investment, Identifier [Axis]: Nuveen, Mid Cap Growth Opportunities
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:NuveenMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 1,090
Investment, Identifier [Axis]: Nuveen, Real Estate Securities
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:NuveenMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 245
Investment, Identifier [Axis]: Nuveen, Small Cap Select
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:NuveenMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,797
Investment, Identifier [Axis]: PIMCO, Total Return Institutional
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:PimcoMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 1,992
Investment, Identifier [Axis]: Principal Global Investors, Government Money Market R6 Fund
Schedule of Assets
EBP, Asset Held for Investment, Party-in-Interest [true false]	true
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:PrincipalGlobalInvestorsMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 5,465
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2010
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 270
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2015
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 167
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2020
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,314
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2025
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 7,774
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2030
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 14,271
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2035
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 15,245
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2040
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 12,407
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2045
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 8,114
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2050
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 8,596
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2055
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 5,760
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2060
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 4,556
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2065
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,387
Investment, Identifier [Axis]: T. Rowe Price, Retirement 2070
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 11
Investment, Identifier [Axis]: T. Rowe Price, Retirement Balanced
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:T.RowePriceMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 2,053
Investment, Identifier [Axis]: Vanguard Group, Inflation-Protected Securities Admiral
Schedule of Assets
EBP, Investment, Issuer Name [Extensible Enumeration]	mec:VanguardGroupMember
EBP, Investment, Current Value, Type [Extensible Enumeration]	Mutual funds
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration]	us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
Current Value	$ 628
Mutual funds
Schedule of Assets
Current Value	$ 139,903

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Current value of investment, excluding plan interest in master trust, in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract.

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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.

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