Mayville Engineering (MEC) 10-Q 6 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 03, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Registrant Name	Mayville Engineering Company, Inc.
Entity Central Index Key	0001766368
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	MEC
Security Exchange Name	NYSE
Entity File Number	001-38894
Entity Incorporation, State or Country Code	WI
Entity Tax Identification Number	39-0944729
Entity Address, Address Line One	715 South Street
Entity Address, City or Town	Mayville
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53050
City Area Code	920
Local Phone Number	387-4500
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		19,827,016

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 13,001	$ 1
Receivables, net of allowances for doubtful accounts of $1,119 at March 31, 2020 and $526 at December 31, 2019	49,449	40,188
Inventories, net	45,824	45,692
Tooling in progress	3,118	1,589
Prepaid expenses and other current assets	2,392	3,007
Total current assets	113,784	90,477
Property, plant and equipment, net	121,696	125,063
Goodwill	71,535	71,535
Intangible assets-net	69,497	72,173
Capital lease, net	3,064	3,227
Other long-term assets	1,024	1,107
Total	380,600	363,582
LIABILITIES, TEMPORARY EQUITY, AND SHAREHOLDERS’ EQUITY
Accounts payable	33,433	32,173
Current portion of capital lease obligation	605	598
Accrued liabilities:
Salaries, wages, and payroll taxes	7,530	5,752
Profit sharing and bonus	1,548	6,229
Other current liabilities	2,976	3,439
Total current liabilities	46,092	48,191
Bank revolving credit notes	87,793	72,572
Capital lease obligation, less current maturities	2,532	2,687
Deferred compensation and long-term incentive, less current portion	24,265	24,949
Deferred income tax liability	14,895	14,188
Other long-term liabilities	100	100
Total liabilities	175,677	162,687
Common shares, no par value, 75,000,000 authorized, 20,845,693 shares issued at March 31, 2020 and December 31, 2019
Additional paid-in-capital	187,643	183,687
Retained earnings	22,140	22,090
Treasury shares at cost, 1,018,677 shares at March 31, 2020 and 1,213,482 at December 31, 2019	(4,860)	(4,882)
Total shareholders’ equity	204,923	200,895
Total	$ 380,600	$ 363,582

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Receivables, net of allowances for doubtful accounts	$ 1,119	$ 526
Common Stock, No Par Value
Common Stock, Shares Authorized	75,000,000	75,000,000
Common Stock, Shares, Issued	20,845,693	20,845,693
Treasury stock at cost	1,018,677	1,213,482

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net sales	$ 108,605	$ 143,732
Cost of sales	96,762	124,153
Amortization of intangibles	2,677	2,677
Profit sharing, bonuses, and deferred compensation	1,325	1,750
Employee stock ownership plan expense	675	1,500
Other selling, general and administrative expenses	5,599	6,723
Contingent consideration revaluation		869
Income from operations	1,567	6,060
Interest expense	(826)	(2,832)
Income before taxes	741	3,228
Income tax expense	691	769
Net income and comprehensive income	50	2,459
Earnings per share
Net income available to shareholders	$ 50	$ 2,459
Basic and diluted earnings per share	$ 0	$ 0.18
Basic and diluted weighted average shares outstanding	19,533,533	13,443,484
Tax-adjusted pro forma information
Net income available to shareholders	$ 50	$ 2,459
Pro forma provision for income taxes		70
Pro forma net income	$ 50	$ 2,389
Pro forma basic and diluted earnings per share	$ 0	$ 0.18
Basic and diluted weighted average shares outstanding	19,533,533	13,443,484

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical)	3 Months Ended
	Mar. 31, 2019
Effective income tax rate reconciliation	26.00%

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 50	$ 2,459
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	5,603	4,973
Amortization	2,677	2,677
Stock-based compensation expense	1,582
Allowance for doubtful accounts	594	(42)
Inventory excess and obsolescence reserve	712
Costs recognized on step-up of acquired inventory		395
Contingent consideration revaluation		869
Gain on disposal of property, plant and equipment	(82)	(10)
Deferred compensation and long-term incentive	(684)	1,147
Other non-cash adjustments	85	96
Changes in operating assets and liabilities – net of effects of acquisition:
Accounts receivable	(9,855)	(15,419)
Inventories	(844)	(470)
Tooling in progress	(1,529)	(354)
Prepaids and other current assets	615	(914)
Accounts payable	1,538	5,892
Deferred income taxes	706
Accrued liabilities, excluding long-term incentive	1,465	(2,799)
Net cash provided by (used in) operating activities	2,633	(1,500)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property, plant and equipment	(2,376)	(8,151)
Proceeds from sale of property, plant and equipment	104	9
Net cash used in investing activities	(2,272)	(8,142)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from bank revolving credit notes	87,118	117,666
Payments on bank revolving credit notes	(71,897)	(110,906)
Repayments of other long-term debt		(107)
Purchase of treasury stock	(2,435)
Payments on capital leases	(147)	(73)
Net cash provided by financing activities	12,639	6,580
Net increase (decrease) in cash and cash equivalents	13,000	(3,061)
Cash and cash equivalents at beginning of period	1	3,089
Cash and cash equivalents at end of period	13,001	28
Supplemental disclosure of cash flow information:
Cash paid for interest	1,596	2,966
Cash paid for taxes	15	140
Non-cash construction in progress in accounts payable	$ 474	$ 2,004

Condensed Consolidated Statem_4

Condensed Consolidated Statement of Shareholders' Equity - 3 months ended Mar. 31, 2020 - USD ($) $ in Thousands	Total	Additional Paid-in Capital [Member]	Treasury Shares [Member]	Retained Earnings [Member]
Beginning, Balance at Dec. 31, 2019	$ 200,895	$ 183,687	$ (4,882)	$ 22,090
Net Income	50			50
Purchase of treasury stock	(2,435)		(2,435)
ESOP contribution	4,831	2,374	2,457
Stock-based compensation	1,582	1,582
Ending, Balance at Mar. 31, 2020	$ 204,923	$ 187,643	$ (4,860)	$ 22,140

Basis of presentation

Basis of presentation	3 Months Ended
	Mar. 31, 2020
Basis Of Presentation [Abstract]
Basis of presentation	Note 1. Basis of presentation The interim unaudited consolidated financial statements of Mayville Engineering Company, Inc. and subsidiaries (MEC, the Company, we, our, us or similar terms) presented here have been prepared in accordance with the accounting principles generally accepted in the United States of America (GAAP) and with instructions to Form 10-Q and Article 10 of Regulation S-X. They reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the results and position for the interim unaudited periods presented. All intercompany balances and transactions have been eliminated in consolidation. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. These interim unaudited Condensed Consolidated Financial Statements should be read in conjunction with the Company’s consolidated financial statements and notes thereto for the year ended December 31, 2019, included in the Company’s Annual Report on Form 10-K. A summary of the Company’s significant accounting policies is included in the Company’s 2019 financial statements in the Annual Report on Form 10-K. The Company followed these policies in preparation of the interim unaudited Condensed Consolidated Financial Statements. Nature of Operations MEC is a leading U.S.-based value-added manufacturing partner that provides a broad range of prototyping and tooling, production fabrication, coating, assembly and aftermarket components. Our customers operate in diverse end markets, including heavy- and medium-duty commercial vehicles, construction, powersports, agriculture, military and other end markets. Along with process engineering and development services, MEC maintains an extensive manufacturing infrastructure with 20 facilities across eight states. These facilities make it possible to offer conventional and CNC stamping, shearing, fiber laser cutting, forming, drilling, tapping, grinding, tube bending, machining, welding, assembly and logistic services. MEC also possesses a broad range of finishing capabilities including shot blasting, e-coating, powder coating, wet spray and military grade chemical agent resistant coating (CARC) painting. Our one operating segment focuses on producing metal components that are used in a broad range of heavy- and medium-duty commercial vehicles, construction, powersports, agricultural, military and other products. In May 2019, we completed our initial public offering (IPO). In conjunction with the IPO, the Company’s legacy business converted from an S corporation to a C corporation. As a result, the consolidated business is subject to paying federal and state corporate income taxes on its taxable income from May 9, 2019 forward. Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment In December 2019, the FASB issued ASU 2019-12, Income Taxes A summary of the Company’s evaluation of other recent accounting pronouncements is included in the Company’s 2019 financial statements in its Annual Report on Form 10-K for the year ended December 31, 2019.

IPO

IPO	3 Months Ended
	Mar. 31, 2020
Initial Public Offering [Abstract]
IPO	Note 2. IPO The IPO of shares of the Company’s common stock was completed in May 2019. In connection with the offering, the Company initially sold 6,250,000 shares of common stock at $17 per share generating proceeds of $99,344, net of underwriting discounts and commissions. Additional shares were also sold under an option granted to the underwriters that same month, resulting in a sale of an additional 152,209 shares of common stock at $17 per share, generating additional proceeds of $2,419, net of underwriting discounts and commissions. In conjunction with the IPO, the Company issued a stock dividend specific to pre-IPO shares, of approximately 1,334.34-for-1, resulting in the conversion of 10,075 shares in our Employee Stock Ownership Plan to 13,443,484 shares. IPO proceeds were used to pay down certain indebtedness.

Select balance sheet data

Select balance sheet data	3 Months Ended
	Mar. 31, 2020
Select Balance Sheet Data [Abstract]
Select balance sheet data	Note 3. Select balance sheet data Inventory Inventories as of March 31, 2020 and December 31, 2019 consist of: March 31, 2020 December 31, 2019 Finished goods and purchased parts $ 28,283 $ 28,664 Raw materials 11,525 10,834 Work-in-process 6,016 6,194 Total $ 45,824 $ 45,692 Property, plant and equipment Property, plant and equipment as of March 31, 2020 and December 31, 2019 consist of: Useful Lives Years* March 31, 2020 December 31, 2019 Land Indefinite $ 1,264 $ 1,264 Land improvements 15-39 3,169 3,169 Building and building improvements 15-39 58,373 58,021 Machinery, equipment and tooling 3-10 205,813 204,248 Vehicles 5 3,718 3,738 Office furniture and fixtures 3-7 15,763 15,469 Construction in progress N/A 2,875 3,154 Total property, plant and equipment, gross 290,975 289,063 Less accumulated depreciation 169,279 164,000 Total property, plant and equipment, net $ 121,696 $ 125,063 Goodwill Changes in goodwill between December 31, 2019 and March 31, 2020 consist of: Balance as of December 31, 2019 $ 71,535 Impairment — Balance as of March 31, 2020 $ 71,535 Intangible Assets The following is a listing of intangible assets, the useful lives in years (amortization period) and accumulated amortization as of March 31, 2020 and December 31, 2019: Useful Lives Years March 31, 2020 December 31, 2019 Amortizable intangible assets: Customer relationships and contracts 9-12 $ 78,340 $ 78,340 Trade name 10 14,780 14,780 Non-compete agreements 5 8,800 8,800 Patents 19 24 24 Accumulated amortization (36,259 ) (33,582 ) Total amortizable intangible assets, net 65,685 68,362 Non-amortizable brand name 3,811 3,811 Total intangible assets, net $ 69,497 $ 72,173 Non-amortizable brand name is tested annually for impairment. Changes in intangible assets between December 31, 2019 and March 31, 2020 consist of: Balance as of December 31, 2019 $ 72,173 Amortization expense (2,677 ) Balance as of March 31, 2020 $ 69,497 Amortization expense was $2,677 and $2,677 for each of the three months ended March 31, 2020 and 2019. Future amortization expense is expected to be as followed: Year ending December 31, 2020 $ 10,706 2021 $ 10,706 2022 $ 6,952 2023 $ 6,866 2024 $ 5,192

Bank revolving credit notes

Bank revolving credit notes	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Bank revolving credit notes	Note 4. Bank revolving credit notes On September 26, 2019, and as last amended as of December 31, 2019, we entered into an amended and restated credit agreement (A&R Credit Agreement) with certain lenders and Wells Fargo Bank, National Association, as administrative agent. The A&R Credit Agreement provides for a $200,000 revolving credit facility (the Revolving Loan), with a letter of credit sub-facility in an aggregate amount not to exceed $5,000, and a swingline facility in an aggregate amount of $20,000. The A&R Credit Agreement also provides for an additional $100,000 of debt capacity through an accordion feature. All amounts borrowed under the A&R Credit Agreement mature on September 26, 2024. The A&R Credit Agreement contains usual and customary negative covenants for agreements of this type, including, but not limited to, restrictions on our ability to, subject to certain exceptions, create, incur or assume indebtedness, create or incur liens, make certain investments, merge or consolidate with another entity, make certain asset dispositions, pay dividends or other distributions to shareholders, enter into transactions with affiliates, enter into sale leaseback transactions or make capital expenditures. The A&R Credit Agreement also requires us to satisfy certain financial covenants, including a minimum interest coverage ratio of 3.00 to 1.00. At March 31, 2020, our interest coverage ratio was 9.21 to 1.00. The A&R Credit Agreement also requires us to maintain a consolidated total leverage ratio not to exceed 3.25 to 1.00, although such leverage ratio can be increased in connection with certain acquisitions. At March 31, 2020, our consolidated total leverage ratio was 1.84 to 1.00. Despite the strength and reputation of our lenders, the Company drew down $13,000 from the revolver and deposited it into a money market account in March 2020 to ensure liquidity due to the uncertainty of the COVID-19 impact on the bank industry in the most extreme of circumstances. The need for this liquidity will continue to be evaluated and will be modified as the circumstances warrant. Had the $13,000 draw down on the revolver not occurred, our consolidated total leverage ratio would have been 1.58 to 1.00. Under the agreement, interest is payable monthly at the adjusted London Interbank Offered Rate (LIBOR) plus an applicable margin based on the current funded indebtedness to adjusted EBITDA ratio. The interest rate was 3.125% and 3.25% as of March 31, 2020 and December 31, 2019, respectively. Additionally, the agreement has a fee on the average daily unused portion of the aggregate unused revolving commitments. This fee was 0.20% as of March 31, 2020 and December 31, 2019. The Company was in compliance with all financial covenants of its credit agreements as of March 31, 2020 and December 31, 2019. The amount borrowed on the revolving credit notes was $87,793 and $72,572 as of March 31, 2020 and December 31, 2019, respectively.

Capital lease obligation

Capital lease obligation	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Capital lease obligation	Note 5. Capital lease obligation Capital leases consist of equipment with a capitalized cost of $3,825 at March 31, 2020 and December 31, 2019, and accumulated depreciation of $761 and $598 at March 31, 2020 and December 31, 2019, respectively. Depreciation of $161 and $73 was recognized on the capital lease assets during the three months ended March 31, 2020 and 2019, respectively. Non-cash capital lease transactions amounted to zero for Year ending December 31, 2020 (remainder) $ 551 2021 734 2022 734 2023 734 2024 514 Thereafter 226 Total 3,493 Less payment amount allocated to interest 356 Present value of capital lease obligation $ 3,137 Current portion of capital lease obligation 605 Long-term portion of capital lease obligation 2,532 Total capital lease obligation $ 3,137

Operating lease obligation

Operating lease obligation	3 Months Ended
	Mar. 31, 2020
Lessee Disclosure [Abstract]
Operating lease obligation	Note 6. Operating lease obligation Operating leases relate to property, plant and equipment. Future minimum lease payments required under the leases are as follows: Year ending December 31, 2020 (remainder) $ 2,299 2021 2,507 2022 1,704 2023 1,560 2024 757 Thereafter 2,094 Total $ 10,921 The Company leases certain office space, warehousing facilities, equipment and vehicles under operating lease arrangements with third-party lessors. These lease arrangements expire at various time through December 2028. Total rent expense under the arrangements was approximately $1,061 and $1,130 for the three months ended March 31, 2020 and 2019, respectively.

Employee stock ownership plan

Employee stock ownership plan	3 Months Ended
	Mar. 31, 2020
Employee Stock Ownership Plan E S O P Shares In E S O P [Abstract]
Employee stock ownership plan	Note 7. Employee stock ownership plan Under the Mayville Engineering Company, Inc. Employee Stock Ownership Plan (the ESOP), the Company makes annual contributions to the trust for the benefit of eligible employees in the form of cash or shares of common stock of the Company. Prior to December 31, 2019, the annual contribution was discretionary except that it must have been at least 3% of the compensation for all safe harbor participants for the plan year. Beginning on January 1, 2020, all contributions are discretionary. For the three months ended March 31, 2020 and 2019, the Company’s ESOP expense amounted to $675 and $1,500, respectively. At various times following death, disability, retirement or termination of employment, an ESOP participant is entitled to receive their ESOP account balance in accordance with various distribution methods as permitted under the policies adopted by the ESOP. Prior to the IPO, all distributions were paid to participants in cash. As of March 31, 2020, and December 31, 2019, the ESOP shares consisted of 11,653,776 and 11,790,113 in allocated shares, respectively. Prior to its IPO, the Company was obligated to repurchase shares in the trust that were not distributed to ESOP participants as determined by the ESOP trustees, and thus the shares were mandatorily redeemable. Subsequent to the IPO, shares are sold in the public market.

Retirement plans

Retirement plans	3 Months Ended
	Mar. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Retirement Plans	Note 8. Retirement plans The Mayville Engineering Company Inc. 401(k) Plan (the 401(k) Plan) covers substantially all employees meeting certain eligibility requirements. The 401(k) Plan is a defined contribution plan and is intended for eligible employees to defer tax-free contributions to save for retirement. Employees may contribute up to 50% of their eligible compensation plan to the 401(k) Plan, subject to the limits of Section 401(k) of the Internal Revenue Code. The 401(k) Plan also provides for employer discretionary profit sharing contributions and the Board of Directors may authorize discretionary profit sharing contributions (which are usually approved at the end of each calendar year).

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income taxes	Note 9. Income taxes On a quarterly basis, the Company estimates its effective tax rate for the full fiscal year and records a quarterly income tax provision based on the anticipated rate. As the year progresses, the Company will refine its estimate based on facts and circumstances by each tax jurisdiction. For the three months ended March 31, 2020, income tax expense was estimated at $691 and the effective tax rate (ETR) from continuing operations was 27.69% • For the three months ended March 31, 2020, we recorded a discrete tax benefit of approximately $12 as a result of estimated non-deductible executive compensation in excess of the $1,000 per individual limitation under Section 162(m) of the Internal Revenue Code. The removal was in addition to the amount originally estimated in our tax provision for the year ended December 31, 2019. This decreased the effective tax rate by 1.58% for the three months ended March 31, 2020. • For the three months ended March 31, 2020, we recorded a discrete tax expense of approximately $483 as a result of the removal of a deferred tax asset related to loan fee amortization. This increased the effective tax rate by 65.09% For the three months ended March 31, 2019, income tax expense was estimated at $769 and the ETR from continuing operations was 30.35% The calculation of our tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations in these jurisdictions. Accounting Standards Codification (ASC) Topic 740, Income Taxes Based on the Company’s evaluation, it has been concluded that there are no significant uncertain tax positions requiring recognition in the Company’s financial statements as of March 31, 2020 or December 31, 2019. Prior to the Company’s IPO, the Company’s legacy business was an S Corporation, where substantially all taxes were passed to the shareholders and the Company did not pay federal or state corporate income taxes on its taxable income. In connection with the IPO, the Company’s legacy business converted to a C Corporation. As a result, the consolidated business is subject to paying federal and state corporate income taxes on its taxable income from May 9, 2019 forward. Upon the Company’s conversion from a non-taxable entity to a taxable entity, we established an opening deferred tax asset of $784 as a result of evaluating estimated temporary differences that existed on this date. The Company’s policy for recording interest and penalties associated with potential income tax audits is to record such expense as a component of income tax expense. There were no amounts for penalties or interest recorded as of March 31, 2020. Management is currently unaware of any issues under review that could result in significant payments, accruals or material deviations from its positions.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Contingencies	Note 10. Contingencies From time to time, the Company may be involved in various claims and lawsuits, both for and against the Company, arising in the normal course of business. Although the results of litigation and claims cannot be predicted with certainty, in management’s opinion, either the likelihood of loss is remote, or any reasonably possible loss associated with the resolution of such proceedings is not expected to have a material adverse impact on the consolidated financial statements.

Deferred compensation

Deferred compensation	3 Months Ended
	Mar. 31, 2020
Deferred Compensation Liability [Abstract]
Deferred compensation	Note 11. Deferred compensation The Mayville Engineering Deferred Compensation Plan is available for certain employees designated to be eligible to participate by the Company and approved by the Board of Directors. Eligible employees may elect to defer a portion of his or her compensation for any plan year and the deferral cannot exceed 50% of the participant’s base salary and may include the participant’s annual short-term cash incentive up to 100%. The participant’s election must be made prior to the first day of the plan year. An employer contribution will be made for each participant to reflect the amount of any reduced allocations to the ESOP and/or 401(k) employer contributions due solely to the participant’s deferral amounts, as applicable. In addition, a discretionary amount may be awarded to a participant by the Company. Prior to the IPO, all deferrals were deemed to have been invested in the Company’s common stock at a price equal to the share value on the date of deferral and the value of the account increased or decreased with the change in the value of the stock. Individual accounts are maintained for each participant. Each participant’s account is credited with the participant’s deferred compensation and investment income or loss, reduced for charges, if any. For the period subsequent to the IPO, deferrals are invested in an investment vehicle based on the options made available to the participant (which does not include Company stock). The deferred compensation plan provides benefits payable upon separation of service or death. Payments are to be made 30 days after date of separation from service, either in a lump-sum payment or up to five annual installments as elected by the participant when the participant first elects to defer compensation. The deferred compensation plan is non-funded, and all future contributions are unsecured in that the employees have the status of a general unsecured creditor of the Company and the agreements constitute a promise by the Company to make benefit payments in the future. During the three months ended March 31, 2020 and 2019, eligible employees elected to defer compensation of $29 and $1,147, respectively. As of March 31, 2020, and December 31, 2019, the total amount accrued for all benefit years under this plan was $24,265 and $24,949, respectively, which is included within the deferred compensation and long-term incentive on the Condensed Consolidated Balance Sheets. These amounts include the initial deferral of compensation as adjusted for (a) subsequent changes in the share value of the Company stock pursuant to the IPO or (b) following the IPO in the investment options chosen by the participants. Total expense for the deferred compensation plan for the three months ended March 31, 2020 and 2019 amounted to $(607) and $1,147, respectively. These expenses are included in profit sharing, bonuses and deferred compensation on the Condensed Consolidated Statements of Comprehensive Income (Loss).

Long-Term incentive plan

Long-Term incentive plan	3 Months Ended
	Mar. 31, 2020
Share Based Compensation [Abstract]
Long-Term incentive plan	Note 12. Long-Term incentive plan Prior to the IPO, The LTIP was non-funded and each participant in the plan was considered a general unsecured creditor of the Company and each agreement constituted a promise by the Company to make benefit payments if the future conditions were met, or if discretion is exercised in favor of a benefit payment. The qualifying conditions for each award granted under the plan included a minimum increase in the aggregate fair value of the Company of 12% during the three-year performance period and the eligible participants must have been employed by the Company on the date of the cash payment or have retired after attaining age 65, died or become disabled during the period from the beginning of the performance period to the date of payment. If the qualifying conditions were not attained, discretionary payments were made, up to a maximum amount specified in each award agreement. Discretionary payments were determined by the Compensation Committee of the Board of Directors (for payment to the Chief Executive Officer of the Company) and by the Chief Executive Officer (for payments to other participants in the plan). If a participant was not employed throughout the performance period due to retirement, death or disability, their maximum benefit was prorated based on the number of days employed by the Company during the performance periods. The LTIP was terminated in May 2019 in conjunction with the IPO. Total expense for the long-term incentive plan for the three months ended March 31, 2019 amounted to $79. These expenses are included in profit sharing, bonuses and deferred compensation on the Condensed Consolidated Statements of Comprehensive Income (Loss).

Self-Funded insurance

Self-Funded insurance	3 Months Ended
	Mar. 31, 2020
Insurance [Abstract]
Self-Funded Insurance	Note 13. Self-Funded insurance The Company is self-funded for the medical benefits provided to its employees and their dependents. Healthcare costs are expensed as incurred and are based upon actual claims paid, reinsurance premiums, administration fees, and estimated unpaid claims. As of March 31, 2020, the Company has consolidated benefit plans with no specific stop loss and an aggregate stop loss to limit risk. Annual expense related to this contract was approximately $5,904 and $5,163 for the three months ended March 31, 2020 and 2019, respectively. An estimated accrued liability of approximately $1,492 and $1,316 was recorded as of March 31, 2020 and December 31, 2019, respectively, for estimated unpaid claims and is included within other current liabilities on the Condensed Consolidated Balance Sheets.

Segments

Segments	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segments	Note 14. Segments The Company applies the provisions of ASC Topic 280, Segment Reporting

Fair value of financial instrum

Fair value of financial instruments	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair value of financial instruments	Note 15. Fair value of financial instruments Fair value provides information on what the Company may realize if certain assets were sold or might pay to transfer certain liabilities based upon an exit price. Financial assets and liabilities that are measured and reported at fair value are classified into a three-level hierarchy that prioritizes the inputs used in the valuation process. A financial instrument’s categorization within the valuation hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The hierarchy is based on the observability and objectivity of the pricing inputs as follows: • Level 1 – Quoted prices in active markets for identical assets or liabilities. • Level 2 – Significant directly observable data (other than Level 1 quoted prices) or significant indirectly observable data through corroboration with observable market data. Inputs would normally be (i) quoted prices in active markets for similar assets or liabilities, (ii) quoted prices in inactive markets for identical or similar assets or liabilities or (iii) information derived from or corroborated by observable market data. Long-term debt is classified as a Level 2 fair value input. • Level 3 – Prices or valuation techniques that require significant unobservable data inputs. These inputs would normally be the Company’s own data and judgements about assumptions that market participants would use in pricing the asset or liability. The following table lists the Company’s financial assets and liabilities accounted for at fair value by the fair value hierarchy: Fair Value Measurements at Report Date Using Balance at March 31, 2020 (Level 1) (Level 2) (Level 3) Deferred compensation $ 24,265 $ 3,691 $ 20,574 $ — Total $ 24,265 $ 3,691 $ 20,574 $ — Fair Value Measurements at Report Date Using Balance at December 31, 2019 (Level 1) (Level 2) (Level 3) Deferred compensation $ 24,949 $ 2,470 $ 22,479 $ — Total $ 24,949 $ 2,470 $ 22,479 $ — Fair value measurements for the Company’s cash and cash equivalents are classified based upon Level 1 measurements because such measurements are based upon quoted market prices in active markets for identical assets. Accounts receivable, accounts payable, long-term debt and accrued liabilities are recorded in the financial statements at cost and approximate fair value. Deferred compensation liabilities are recorded at amounts due to participants at the time of deferral. Deferrals are invested in an investment vehicle based on the options made available to the participant, considered to be Level 1 and Level 2 on the fair value hierarchy, with the majority of the balance as Level 2. The change in fair value is recorded in the Profit sharing, bonuses, and deferred compensation line item on the Condensed Consolidated Statements of Comprehensive Income (Loss). The balance due to participants is reflected on the Deferred compensation and long-term incentive line item on the Condensed Consolidated Balance Sheets. The Company’s non-financial assets such as intangible assets and property, plant, and equipment are re-measured at fair value when there is an indication of impairment and adjusted only when an impairment charge is recognized.

Common Equity

Common Equity	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Common Equity	Note 16 – Common Equity On May 13, 2019 the Company issued a stock dividend specific to pre-IPO shares, of approximately 1,334.34-for-1. The share dividend was accounted for as a 1,334.34-for-1 stock split and is retroactively reflected in these consolidated financial statements. All share redemption provisions were removed effective with the IPO.

Temporary Equity

Temporary Equity	3 Months Ended
	Mar. 31, 2020
Temporary Equity [Abstract]
Temporary Equity	Note 17 – Temporary Equity Prior to our IPO in May 2019, our common stock was considered redeemable under GAAP because of certain repurchase obligations related to the Mayville Engineering Company, Inc. ESOP. As a result, all common shares were recorded as temporary equity (redeemable common shares) on the consolidated balance sheets at their redemption values as of the respective balance sheet dates. All contractual redemption features were removed at the time of the IPO. As a consequence, all outstanding shares of common stock ceased to be considered temporary equity and were reclassified to Shareholders’ Equity, including the associated balances of retained earnings. As the common shares have no par value, the amounts recorded in temporary equity for the share redemption value were recorded to additional paid-in capital within Shareholders’ Equity upon the transfer. The following table shows all changes to temporary equity during the three months ended March 31, 2019. Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings As of January 1, 2019 $ 133,806 $ (57,659 ) $ 26,842 Net Income — — 2,459 As of March 31, 2019 $ 133,806 $ (57,659 ) $ 29,301

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue Recognition	Note 18 – Revenue Recognition Contract Assets and Contract Liabilities The Company has contract assets and contract liabilities, which are included in other current assets and other current liabilities on the consolidated balance sheet, respectively. Contract assets include products where the Company has satisfied its performance obligation, but receipt of payment is contingent upon delivery. Contract liabilities include deferred tooling revenue, where the performance obligation was not met. The performance obligation is satisfied when the tooling is completed and the customer signs off through the Product Part Approval Process (PPAP). At this time, the tool is placed into service and the cost to build the tooling is released from the balance sheet and included in cost of goods sold. The Company’s contracts with customers are short-term in nature; therefore, revenue is typically recognized, billed and collected within a 12-month period. The following table reflects the changes in our contract assets and liabilities during the three months ended March 31, 2020. (in thousands) Contract Assets Contract Liabilities As of January 1, 2020 $ 1,589 $ 914 Net Activity 1,529 328 As of March 31, 2020 $ 3,118 $ 1,242 Disaggregated Revenue The following table represents a disaggregation of revenue by product category: Three Months Ended March 31, 2020 2019 Outdoor sports $ 1,771 $ 1,859 Fabrication 69,793 91,153 Performance structures 16,639 19,807 Tube 14,954 20,857 Tank 6,718 11,605 Total 109,875 145,281 Intercompany sales elimination (1,270 ) (1,549 ) Total, net sales $ 108,605 $ 143,732

Concentration of major customer

Concentration of major customers	3 Months Ended
	Mar. 31, 2020
Risks And Uncertainties [Abstract]
Concentration of major customers	Note 19 – Concentration of major customers The following customers accounted for 10% or greater of the Company’s recorded net sales and net trade receivables: Net Sales Accounts Receivable Three Months Ended March 31, As of As of 2020 2019 March 31, 2020 December 31, 2019 Customer A 16.2 % 17.0 % 13.5 % <10 % B 10.8 % 14.1 % <10 % <10 % C 10.2 % <10 % <10 % <10 % D 11.8 % 11.6 % <10 % <10 % E <10 % <10 % 11.1 % 10.4 % F <10 % <10 % 14.2 % 13.5 %

Stock based compensation

Stock based compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock based compensation	Note 20 – Stock based compensation The Mayville Engineering Company, Inc. 2019 Omnibus Incentive Plan provides the Company the ability to grant monetary payments based on the value of its common stock, up to two million shares. The Company recognizes stock-based compensation using the fair value provisions prescribed by ASC Topic 718, Compensation – Stock Compensation Cancellations and forfeitures are accounted for as incurred. On February 27, 2020, the Company granted stock awards, including restricted stock units and options with a 2-year requisite service period to key employees. Stock awards were also granted on May 8, 2019. There were no stock awards granted prior to this. For units, fair value is equivalent to the stock price at the date of grant. The Black-Scholes option pricing model is utilized to determine fair value for options. Stock awards vest on their annual anniversary dates based on the passage of time. The related compensation expense for each award is recognized on a straight-line basis over the requisite service period. The Company’s stock-based compensation expense by award type is summarized as follows: Three Months Ended March 31, 2020 2019 One-time IPO unit awards $ 725 $ — Unit awards 564 — Option awards 293 — Stock based compensation expense, net of tax $ 1,582 $ — Unrecognized stock-based compensation expense was $6,797 as of March 31, 2020. This amount will be expensed over the requisite service period from which individual award values relate, up to February 27, 2022. Unrecognized stock-based compensation expense specific to the one-time IPO unit awards was $304 as of March 31, 2020, which will be fully expensed as of June 30, 2020. For options, we used the Black-Scholes option pricing model to estimate the fair value of stock option awards. The fair value of options granted on February 27, 2020 was $2.84. These options have a contractual life of 10 years and a requisite service period of 2-years with 50% vesting on the annual anniversary dates of grant. The determination of the fair value is affected by the following assumptions and inputs: Assumptions Input Stock price at date of grant/exercise price $ 7.12 Expected term (in years) 5.75 Estimated volatility 41.2 % Estimated risk-free rate of return 1.2 % Expected dividend yield 0.0 % The Company does not have historical option exercise data to estimate the expected term. For the options granted on February 27, 2020, the Company utilized the simplified method prescribed by Staff Accounting Bulletin ( SAB Topic 14 No units or options were vested and no options were exercisable as of March 31, 2020. The Company’s activity for restricted stock units and options is summarized as follows: Units Options Number of Units Weighted Average Grant Date Fair Value Number of Options Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Contractual Life Remaining Nonvested, as of December 31, 2019 326,288 $ 17.00 273,479 $ 6.07 $ 17.00 9.11 Grants 340,177 $ 7.12 718,489 $ 2.84 $ 7.12 9.91 Forfeitures — — — — — — Vested — — — — — — Nonvested, as of March 31, 2020 666,465 $ 11.96 991,968 $ 3.73 $ 9.84 9.69

Subsequent events

Subsequent events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent events	Note 21– Subsequent events The company evaluated events and transactions for potential recognition or disclosure in the The coronavirus (COVID-19) pandemic has had, and will continue to have, a negative impact on the Company’s business, financial condition, cash flows and results of operations, although the full extent is uncertain. The Company has taken cost reduction measures in response to the impact of the COVID-19 pandemic on its business including forced vacation, temporary layoffs, permanent layoffs, and other ad-hoc measures, however; nothing has been changed to an extent that would prevent the Company from continuing to adequately serve its customers. The Company is continuing to evaluate its cost structure and may implement additional cost reduction measures as necessary due to economic challenges resulting from the COVID-19 pandemic. As the pandemic continues to rapidly evolve, the extent of the impact on the Company’s business, financial condition, cash flows and results of operations will depend on future developments, all of which are highly uncertain and cannot be predicted at this time.

Basis of presentation (Policies

Basis of presentation (Policies)	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations	Nature of Operations MEC is a leading U.S.-based value-added manufacturing partner that provides a broad range of prototyping and tooling, production fabrication, coating, assembly and aftermarket components. Our customers operate in diverse end markets, including heavy- and medium-duty commercial vehicles, construction, powersports, agriculture, military and other end markets. Along with process engineering and development services, MEC maintains an extensive manufacturing infrastructure with 20 facilities across eight states. These facilities make it possible to offer conventional and CNC stamping, shearing, fiber laser cutting, forming, drilling, tapping, grinding, tube bending, machining, welding, assembly and logistic services. MEC also possesses a broad range of finishing capabilities including shot blasting, e-coating, powder coating, wet spray and military grade chemical agent resistant coating (CARC) painting. Our one operating segment focuses on producing metal components that are used in a broad range of heavy- and medium-duty commercial vehicles, construction, powersports, agricultural, military and other products. In May 2019, we completed our initial public offering (IPO). In conjunction with the IPO, the Company’s legacy business converted from an S corporation to a C corporation. As a result, the consolidated business is subject to paying federal and state corporate income taxes on its taxable income from May 9, 2019 forward.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment In December 2019, the FASB issued ASU 2019-12, Income Taxes A summary of the Company’s evaluation of other recent accounting pronouncements is included in the Company’s 2019 financial statements in its Annual Report on Form 10-K for the year ended December 31, 2019.

Select balance sheet data (Tabl

Select balance sheet data (Tables)	3 Months Ended
	Mar. 31, 2020
Select Balance Sheet Data [Abstract]
Schedule of Inventories	Inventories as of March 31, 2020 and December 31, 2019 consist of: March 31, 2020 December 31, 2019 Finished goods and purchased parts $ 28,283 $ 28,664 Raw materials 11,525 10,834 Work-in-process 6,016 6,194 Total $ 45,824 $ 45,692
Schedule of Property, Plant and Equipment	Property, plant and equipment as of March 31, 2020 and December 31, 2019 consist of: Useful Lives Years* March 31, 2020 December 31, 2019 Land Indefinite $ 1,264 $ 1,264 Land improvements 15-39 3,169 3,169 Building and building improvements 15-39 58,373 58,021 Machinery, equipment and tooling 3-10 205,813 204,248 Vehicles 5 3,718 3,738 Office furniture and fixtures 3-7 15,763 15,469 Construction in progress N/A 2,875 3,154 Total property, plant and equipment, gross 290,975 289,063 Less accumulated depreciation 169,279 164,000 Total property, plant and equipment, net $ 121,696 $ 125,063
Schedule of Changes In Goodwill	Changes in goodwill between December 31, 2019 and March 31, 2020 consist of: Balance as of December 31, 2019 $ 71,535 Impairment — Balance as of March 31, 2020 $ 71,535
Schedule of Listing of Intangible Assets	The following is a listing of intangible assets, the useful lives in years (amortization period) and accumulated amortization as of March 31, 2020 and December 31, 2019: Useful Lives Years March 31, 2020 December 31, 2019 Amortizable intangible assets: Customer relationships and contracts 9-12 $ 78,340 $ 78,340 Trade name 10 14,780 14,780 Non-compete agreements 5 8,800 8,800 Patents 19 24 24 Accumulated amortization (36,259 ) (33,582 ) Total amortizable intangible assets, net 65,685 68,362 Non-amortizable brand name 3,811 3,811 Total intangible assets, net $ 69,497 $ 72,173
Schedule of Changes In Intangible Assets	Changes in intangible assets between December 31, 2019 and March 31, 2020 consist of: Balance as of December 31, 2019 $ 72,173 Amortization expense (2,677 ) Balance as of March 31, 2020 $ 69,497
Schedule of Future Amortization Expense	Future amortization expense is expected to be as followed: Year ending December 31, 2020 $ 10,706 2021 $ 10,706 2022 $ 6,952 2023 $ 6,866 2024 $ 5,192

Capital lease obligation (Table

Capital lease obligation (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of Future Minimum Lease Payments Required Under The Lease	Future minimum lease payments required under the lease are as follows: Year ending December 31, 2020 (remainder) $ 551 2021 734 2022 734 2023 734 2024 514 Thereafter 226 Total 3,493 Less payment amount allocated to interest 356 Present value of capital lease obligation $ 3,137 Current portion of capital lease obligation 605 Long-term portion of capital lease obligation 2,532 Total capital lease obligation $ 3,137

Operating lease obligation (Tab

Operating lease obligation (Tables)	3 Months Ended
	Mar. 31, 2020
Lessee Disclosure [Abstract]
Future Minimum Lease Payments Under Leases	Operating leases relate to property, plant and equipment. Future minimum lease payments required under the leases are as follows: Year ending December 31, 2020 (remainder) $ 2,299 2021 2,507 2022 1,704 2023 1,560 2024 757 Thereafter 2,094 Total $ 10,921

Fair value of financial instr_2

Fair value of financial instruments (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Accounted for at Fair Value by Fair Value Hierarchy	The following table lists the Company’s financial assets and liabilities accounted for at fair value by the fair value hierarchy: Fair Value Measurements at Report Date Using Balance at March 31, 2020 (Level 1) (Level 2) (Level 3) Deferred compensation $ 24,265 $ 3,691 $ 20,574 $ — Total $ 24,265 $ 3,691 $ 20,574 $ — Fair Value Measurements at Report Date Using Balance at December 31, 2019 (Level 1) (Level 2) (Level 3) Deferred compensation $ 24,949 $ 2,470 $ 22,479 $ — Total $ 24,949 $ 2,470 $ 22,479 $ —

Temporary Equity (Tables)

Temporary Equity (Tables)	3 Months Ended
	Mar. 31, 2020
Temporary Equity [Abstract]
Schedule of Changes to Temporary Equity	The following table shows all changes to temporary equity during the three months ended March 31, 2019. Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings As of January 1, 2019 $ 133,806 $ (57,659 ) $ 26,842 Net Income — — 2,459 As of March 31, 2019 $ 133,806 $ (57,659 ) $ 29,301

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Changes in Contract Assets and Liabilities	The following table reflects the changes in our contract assets and liabilities during the three months ended March 31, 2020. (in thousands) Contract Assets Contract Liabilities As of January 1, 2020 $ 1,589 $ 914 Net Activity 1,529 328 As of March 31, 2020 $ 3,118 $ 1,242
Schedule of Disaggregation of Revenue by Product Category	The following table represents a disaggregation of revenue by product category: Three Months Ended March 31, 2020 2019 Outdoor sports $ 1,771 $ 1,859 Fabrication 69,793 91,153 Performance structures 16,639 19,807 Tube 14,954 20,857 Tank 6,718 11,605 Total 109,875 145,281 Intercompany sales elimination (1,270 ) (1,549 ) Total, net sales $ 108,605 $ 143,732

Concentration of major custom_2

Concentration of major customers (Tables)	3 Months Ended
	Mar. 31, 2020
Risks And Uncertainties [Abstract]
Schedules of Major Customer Concentrations	The following customers accounted for 10% or greater of the Company’s recorded net sales and net trade receivables: Net Sales Accounts Receivable Three Months Ended March 31, As of As of 2020 2019 March 31, 2020 December 31, 2019 Customer A 16.2 % 17.0 % 13.5 % <10 % B 10.8 % 14.1 % <10 % <10 % C 10.2 % <10 % <10 % <10 % D 11.8 % 11.6 % <10 % <10 % E <10 % <10 % 11.1 % 10.4 % F <10 % <10 % 14.2 % 13.5 %

Stock based compensation (Table

Stock based compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-based Compensation Expenses	The Company’s stock-based compensation expense by award type is summarized as follows: Three Months Ended March 31, 2020 2019 One-time IPO unit awards $ 725 $ — Unit awards 564 — Option awards 293 — Stock based compensation expense, net of tax $ 1,582 $ —
Summary of Fair Value Assumptions and Inputs	The determination of the fair value is affected by the following assumptions and inputs: Assumptions Input Stock price at date of grant/exercise price $ 7.12 Expected term (in years) 5.75 Estimated volatility 41.2 % Estimated risk-free rate of return 1.2 % Expected dividend yield 0.0 %
Summary of Activity for Restricted Stock Units and Options	The Company’s activity for restricted stock units and options is summarized as follows: Units Options Number of Units Weighted Average Grant Date Fair Value Number of Options Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Contractual Life Remaining Nonvested, as of December 31, 2019 326,288 $ 17.00 273,479 $ 6.07 $ 17.00 9.11 Grants 340,177 $ 7.12 718,489 $ 2.84 $ 7.12 9.91 Forfeitures — — — — — — Vested — — — — — — Nonvested, as of March 31, 2020 666,465 $ 11.96 991,968 $ 3.73 $ 9.84 9.69

Basis of presentation - Additio

Basis of presentation - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020FacilityStateSegment
Basis Of Presentation [Abstract]
Number of facilities operated | Facility	20
Number of states | State	8
Number of operating segments | Segment	1

IPO - Additional Information (D

IPO - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	May 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Initial Public Offering [Line Items]
Conversion of stock Employee Stock Ownership Plan	10,075
Shares in Employee Stock Ownership Plan	13,443,484	11,653,776	11,790,113
Common Stock [Member] | IPO [Member]
Initial Public Offering [Line Items]
Common stock sold	6,250,000
Sale of shares prices	$ 17
Cash inflow of issuance of stock	$ 99,344
Common Stock [Member] | Underwriter [Member] | IPO [Member]
Initial Public Offering [Line Items]
Common stock sold	152,209
Sale of shares prices	$ 17
Cash inflow of issuance of stock	$ 2,419
May 2019 IPO [Member]
Initial Public Offering [Line Items]
Dividend stock split conversion ratio	133434.00%

Select balance sheet data - Sch

Select balance sheet data - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Select Balance Sheet Data [Abstract]
Finished goods and purchased parts	$ 28,283	$ 28,664
Raw materials	11,525	10,834
Work-in-process	6,016	6,194
Total	$ 45,824	$ 45,692

Select balance sheet data - S_2

Select balance sheet data - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 290,975	$ 289,063
Less accumulated depreciation	169,279	164,000
Total property, plant and equipment, net	121,696	125,063
Land [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 1,264	1,264
Property, plant and equipment useful lives	Indefinite
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 3,169	3,169
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	15 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	39 years
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 58,373	58,021
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	15 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	39 years
Machinery, Equipment and Tooling [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 205,813	204,248
Machinery, Equipment and Tooling [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	3 years
Machinery, Equipment and Tooling [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	10 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 3,718	3,738
Property, plant and equipment useful lives	5 years
Office Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 15,763	15,469
Office Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	3 years
Office Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful lives	7 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 2,875	$ 3,154

Select balance sheet data - S_3

Select balance sheet data - Schedule of Changes In Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Select Balance Sheet Data [Abstract]
Balance	$ 71,535
Impairment	0
Balance	$ 71,535

Select balance sheet data - S_4

Select balance sheet data - Schedule of Listing of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Amortizable intangible assets [Abstract]
Accumulated amortization	$ (36,259)	$ (33,582)
Total amortizable intangible assets, net	65,685	68,362
Total intangible assets, net	69,497	72,173
Customer Relationships and Contracts [Member]
Amortizable intangible assets [Abstract]
Amortizable intangible assets, gross	$ 78,340	$ 78,340
Customer Relationships and Contracts [Member] | Minimum [Member]
Amortizable intangible assets [Abstract]
Intangible assets useful Lives	9 years	9 years
Customer Relationships and Contracts [Member] | Maximum [Member]
Amortizable intangible assets [Abstract]
Intangible assets useful Lives	12 years	12 years
Trade Names [Member]
Amortizable intangible assets [Abstract]
Intangible assets useful Lives	10 years	10 years
Amortizable intangible assets, gross	$ 14,780	$ 14,780
Noncompete Agreements [Member]
Amortizable intangible assets [Abstract]
Intangible assets useful Lives	5 years	5 years
Amortizable intangible assets, gross	$ 8,800	$ 8,800
Patents [Member]
Amortizable intangible assets [Abstract]
Intangible assets useful Lives	19 years	19 years
Amortizable intangible assets, gross	$ 24	$ 24
Brand Name [Member]
Amortizable intangible assets [Abstract]
Total intangible assets, net	$ 3,811	$ 3,811

Select balance sheet data - S_5

Select balance sheet data - Schedule of Changes In Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Select Balance Sheet Data [Abstract]
Balance	$ 72,173
Amortization expense	(2,677)	$ (2,677)
Balance	$ 69,497

Select balance sheet data - Add

Select balance sheet data - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Select Balance Sheet Data [Abstract]
Amortization expense	$ 2,677	$ 2,677

Select balance sheet data - S_6

Select balance sheet data - Schedule of Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2020USD ($)
Select Balance Sheet Data [Abstract]
2020	$ 10,706
2021	10,706
2022	6,952
2023	6,866
2024	$ 5,192

Bank revolving credit notes - A

Bank revolving credit notes - Additional Information (Details) - USD ($)	Sep. 26, 2019	Mar. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Line Of Credit Facility [Line Items]
Interest coverage ratio			9.21%
Consolidated leverage ratio			1.84%
Revolving credit notes		$ 87,793,000	$ 87,793,000	$ 72,572,000
COVID-19
Line Of Credit Facility [Line Items]
Consolidated leverage ratio			1.58%
Drew down on revolver and deposited into money market account		13,000,000
A&R Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Minimum interest coverage ratio			3.00%
Maximum consolidated leverage ratio			3.25%
A&R Credit Agreement [Member] | The Agent [Member]
Line Of Credit Facility [Line Items]
Credit agreement additional borrowing capacity through accordion feature	$ 100,000,000
Credit agreement maturity date	Sep. 26, 2024
Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Interest rate			3.125%	3.25%
Revolving commitments fee percentage			0.20%	0.20%
Revolving credit notes		$ 87,793,000	$ 87,793,000	$ 72,572,000
Revolving Credit Facility [Member] | A&R Credit Agreement [Member] | The Agent [Member]
Line Of Credit Facility [Line Items]
Credit agreement borrowing capacity	$ 200,000,000
Letter of Credit Sub-facility [Member] | A&R Credit Agreement [Member] | The Agent [Member]
Line Of Credit Facility [Line Items]
Credit agreement borrowing capacity	5,000,000
Swingline Facility [Member] | A&R Credit Agreement [Member] | The Agent [Member]
Line Of Credit Facility [Line Items]
Credit agreement borrowing capacity	$ 20,000,000

Capital lease obligation - Addi

Capital lease obligation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 3,137
Non-cash capital lease transactions	0	$ 0
Equipment [Member]
Capital Leased Assets [Line Items]
Capitalized cost	3,825		$ 3,825
Capital lease, accumulated depreciation	761		$ 598
Capital lease, depreciation recognized	$ 161	$ 73

Capital lease obligation - Sche

Capital lease obligation - Schedule of Future Minimum Lease Payments Required Under The Lease (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2020 (remainder)	$ 551
2021	734
2022	734
2023	734
2024	514
Thereafter	226
Total	3,493
Less payment amount allocated to interest	356
Present value of capital lease obligation	3,137
Current portion of capital lease obligation	605	$ 598
Long-term portion of capital lease obligation	2,532	$ 2,687
Total capital lease obligation	$ 3,137

Operating lease obligation - Fu

Operating lease obligation - Future Minimum Lease Payments Under Leases (Details) $ in Thousands	Mar. 31, 2020USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2020 (remainder)	$ 2,299
2021	2,507
2022	1,704
2023	1,560
2024	757
Thereafter	2,094
Total	$ 10,921

Operating lease obligation - Ad

Operating lease obligation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lessee Disclosure [Abstract]
Operating lease expiration period	2028-12
Rent expense	$ 1,061	$ 1,130

Employee stock ownership plan -

Employee stock ownership plan - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	May 31, 2019
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Annual contribution vesting percentage			3.00%
Employee stock ownership plan (ESOP), compensation expense	$ 675	$ 1,500
Shares in ESOP	11,653,776		11,790,113	13,443,484
Employee Stock Option [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee stock ownership plan (ESOP), compensation expense	$ 675	$ 1,500

Retirement plans - Additional I

Retirement plans - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Percentage of employee contribution of eligible compensation plan	50.00%

Income taxes - Additional Infor

Income taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax [Line Items]
Income tax expense	$ 691,000	$ 769,000
Effective income tax rate	27.69%	30.35%
Effective income tax rate reconciliation non-deductible executive compensation expense amount	$ 12,000
Individual compensation deductible limit under section 162(m)	$ 1,000,000
Effective income tax rate reconciliation non-deductible executive compensation expense percent	1.58%
Effective income tax rate reconciliation result of removal deferred tax asset amount	$ 483,000
Deferred tax assets tax holiday	784,000
Penalties or interest recorded	$ 0
State and Local Jurisdiction [Member]
Income Tax [Line Items]
Effective income tax rate reconciliation, change in enacted tax rate	65.09%

Deferred compensation - Additio

Deferred compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Description of deferred compensation arrangements	The Mayville Engineering Deferred Compensation Plan is available for certain employees designated to be eligible to participate by the Company and approved by the Board of Directors.
Deferred compensation	$ 1,325	$ 1,750
Deferred compensation cash-based arrangements liability	24,265		$ 24,949
Deferred Profit Sharing [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Deferred compensation	(607)	1,147
Employees [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Deferred compensation	$ 29	$ 1,147
Maximum [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Annual short term cash incentive	100.00%
Deferred compensation arrangements	50.00%

Long-Term incentive plan - Addi

Long-Term incentive plan - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Long term incentives plan terms	Prior to the IPO, the Company’s long-term incentive plan (LTIP) was available for any employee who had been designated to be eligible to participate by the Compensation Committee of the Board of Directors. Annually, the LTIP provided for long-term cash incentive awards to eligible participants based on the Company’s performance over a three-year performance period.
Long-Term Incentive Plan	$ 1,325	$ 1,750
Deferred Bonus [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Long-Term Incentive Plan		$ 79
Chief Executive Officer [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Increase in fair value of long term incentive plan	12.00%
Long term incentive plan	3 years

Self-Funded insurance - Additio

Self-Funded insurance - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Insurance [Abstract]
Estimated accrued liability	$ 1,492		$ 1,316
Reinsured limit of annual aggregate expense	$ 5,904	$ 5,163

Segments - Additional Informati

Segments - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020Segment
Segment Reporting [Abstract]
Number of operating segments	1

Fair value of financial instr_3

Fair value of financial instruments - Schedule of Financial Assets and Liabilities Accounted for at Fair Value by Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 24,265	$ 24,949
Fair Value, Inputs, Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	3,691	2,470
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	20,574	22,479
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	0	0
Deferred Compensation [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	24,265	24,949
Deferred Compensation [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	3,691	2,470
Deferred Compensation [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	20,574	22,479
Deferred Compensation [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 0	$ 0

Common Equity - Additional Info

Common Equity - Additional Information (Details)	May 13, 2019
Equity [Abstract]
Stockholders' equity dividend description	On May 13, 2019 the Company issued a stock dividend specific to pre-IPO shares, of approximately 1,334.34-for-1. The share dividend was accounted for as a 1,334.34-for-1 stock split and is retroactively reflected in these consolidated financial statements. All share redemption provisions were removed effective with the IPO.

Temporary Equity - Schedule of

Temporary Equity - Schedule of Changes to Temporary Equity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Redeemable Common Stock [Member]
Temporary Equity [Line Items]
Beginning, Balance	$ 133,806
Ending, Balance	133,806
Treasury Shares [Member]
Temporary Equity [Line Items]
Beginning, Balance	(57,659)
Ending, Balance	(57,659)
Retained Earnings [Member]
Temporary Equity [Line Items]
Beginning, Balance	26,842
Net Income	2,459
Ending, Balance	$ 29,301

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Changes in Contract Assets and Liabilities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Revenue From Contract With Customer [Abstract]
Contract asset, beginning balance	$ 1,589
Net Activity	1,529
Contract asset, ending balance	3,118
Contract liability, beginning balance	914
Net Activity	328
Contract liability, ending balance	$ 1,242

Revenue Recognition - Schedul_2

Revenue Recognition - Schedule of Disaggregation of Revenue by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Net sales	$ 108,605	$ 143,732
Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	109,875	145,281
Intercompany Sales Elimination
Disaggregation Of Revenue [Line Items]
Net sales	(1,270)	(1,549)
Outdoor Sports | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	1,771	1,859
Fabrication | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	69,793	91,153
Performance structures | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	16,639	19,807
Tube | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	14,954	20,857
Tank | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales	$ 6,718	$ 11,605

Concentration of major custom_3

Concentration of major customers - Schedules of Major Customer Concentrations (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Customer A [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	16.20%	17.00%
Customer A [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage			<10%
Concentration risk percentage	13.50%
Customer B [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	10.80%	14.10%
Customer B [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%		<10%
Customer C [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage		<10
Concentration risk percentage	10.20%
Customer C [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%		<10%
Customer D [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	11.80%	11.60%
Customer D [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%		<10%
Customer E [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%	<10%
Customer E [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	11.10%		10.40%
Customer F [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%	<10%
Customer F [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	14.20%		13.50%

Stock based compensation - Addi

Stock based compensation - Additional Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award requisite service period	2 years
Stock options awarded, value | $	$ 0
Unrecognized stock-based compensation expense | $	$ 6,797
Unrecognized stock-based compensation recognition period	Feb. 27, 2022
Share-based compensation arrangement by share-based payment award, fair value assumptions, method used	Black-Scholes option pricing model
Fair value of the options granted | $ / shares	$ 2.84
Share-based compensation arrangement by share-based payment award, contractual life	10 years
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage	50.00%
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Units, Vested	0
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Vested	0
Number of Options, Exercisable	0
2019 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments based on the value of its common stock	2,000,000
One-time IPO Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense | $	$ 304
Unrecognized stock-based compensation recognition period	Jun. 30, 2020
2020 Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award requisite service period	2 years
Share-based compensation arrangement by share-based payment award, contractual life	10 years
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage	50.00%
Share based compensation arrangement by share based payment award, options average expected term	5 years 9 months
2020 Option [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, options expected term	5 years 6 months
2020 Option [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, options expected term	6 years

Stock based compensation - Summ

Stock based compensation - Summary of Stock-based Compensation Expenses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense, net of tax	$ 1,582
One-time IPO Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense, net of tax	725
Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense, net of tax	564
Option Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense, net of tax	$ 293

Stock based compensation - Su_2

Stock based compensation - Summary of Fair Value Assumptions and Inputs (Details)	3 Months Ended
	Mar. 31, 2020$ / shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock price at date of grant/exercise price	$ 7.12
Expected term (in years)	5 years 9 months
Estimated volatility	41.20%
Estimated risk-free rate of return	1.20%
Expected dividend yield	0.00%

Stock based compensation - Su_3

Stock based compensation - Summary of Activity for Restricted Stock Units and Options (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Grants	$ 2.84
Restricted Stock Units [Member]
Number of Units
Number of Units, Beginning balance	326,288
Number of Units, Grants	340,177
Number of Units, Ending balance	666,465	326,288
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 17
Weighted Average Grant Date Fair Value, Grants	7.12
Weighted Average Grant Date Fair Value, Ending balance	$ 11.96	$ 17
Employee Stock Option [Member]
Number of Options
Number of Options, Beginning balance	273,479
Number of Options, Grants	718,489
Number of Options, Ending balance	991,968	273,479
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 6.07
Weighted Average Grant Date Fair Value, Grants	2.84
Weighted Average Grant Date Fair Value, Ending balance	3.73	$ 6.07
Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning balance	17
Weighted Average Exercise Price, Grants	7.12
Weighted Average Exercise Price, Ending balance	$ 9.84	$ 17
Weighted Average Contractual Life Remaining
Weighted Average Contractual Life Remaining, Beginning balance	9 years 8 months 8 days	9 years 1 month 9 days
Weighted Average Contractual Life Remaining, Grants	9 years 10 months 28 days