Mayville Engineering (MEC) 10-K 2 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 15, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
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 Annual Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		19,545,689
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 272,416,084
Documents Incorporated by Reference	Part III of this report incorporates information by reference to the Registrant’s proxy statement for its 2020 annual meeting of shareholders, which proxy statement will be filed with the Securities and Exchange Commission no later than 120 days after the close of the year ended December 31, 2019.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	May 13, 2019	Dec. 31, 2018
Receivables, net of allowances for doubtful accounts	$ 526		$ 801
Redeemable common shares par value	$ 0		$ 0
Redeemable common shares authorized			60,045,454
Redeemable common shares issued			38,623,806
Treasury stock at cost	1,213,482		25,180,330
Common Stock, Shares Authorized	75,000,000
Common Stock, Shares, Issued	20,845,693
IPO [Member]
Common Stock, Shares Authorized			45,000
Common Stock, Shares, Issued			28,946
Treasury Stock, Shares			18,871
May 2019 IPO [Member]
Dividend stock split conversion ratio		133434.00%

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 1	$ 3,089
Receivables, net of allowances for doubtful accounts of $526 as of December 31, 2019 and $801 as of December 31, 2018	40,188	52,298
Inventories, net	45,692	53,405
Tooling in progress	1,589	2,318
Prepaid expenses and other current assets	3,007	1,649
Total current assets	90,477	112,759
Property, plant and equipment, net	125,063	123,883
Goodwill	71,535	69,437
Intangible assets-net	72,173	82,879
Capital lease, net	3,227	1,953
Other long-term assets	1,107	814
Total	363,582	391,725
LIABILITIES, TEMPORARY EQUITY, AND SHAREHOLDERS’ EQUITY
Accounts payable	32,173	45,992
Current portion of capital lease obligation	598	281
Current portion of long-term debt		8,606
Accrued liabilities:
Salaries, wages, and payroll taxes	5,752	7,548
Profit sharing and bonus	6,229	6,124
Other current liabilities	3,439	14,610
Total current liabilities	48,191	83,161
Bank revolving credit notes	72,572	59,629
Capital lease obligation, less current maturities	2,687	1,697
Other long-term debt, less current maturities		111,675
Deferred compensation and long-term incentive, less current portion	24,949	13,351
Deferred income tax liability	14,188	19,123
Other long-term liabilities	100	100
Total liabilities	162,687	288,736
Commitments and contingencies (see Note 12)
Redeemable common shares, no par value, stated at redemption value of outstanding shares, 60,045,454 shares authorized, 38,623,806 shares issued at December 31, 2018		133,806
Retained earnings		26,842
Treasury shares at cost, 25,180,330 shares at December 31, 2018		(57,659)
Total temporary equity		102,989
Common shares, no par value, 75,000,000 authorized, 20,845,693 shares issued at December 31, 2019
Additional paid-in-capital	183,687
Retained earnings	22,090
Treasury shares at cost, 1,213,482 shares at December 31, 2019	(4,882)
Total shareholders’ equity	200,895
Total	$ 363,582	$ 391,725

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net sales	$ 102,331	$ 128,511	$ 145,130	$ 143,732	$ 91,431	$ 84,338	$ 91,535	$ 87,221	$ 519,704	$ 354,526	$ 313,331
Cost of sales	98,297	113,941	124,595	124,153	81,035	71,517	75,986	75,411	460,986	303,948	278,594
Amortization of intangibles	2,677	2,677	2,677	2,677	1,279	939	939	939	10,706	4,096	3,756
Profit sharing, bonuses, and deferred compensation	(153)	678	22,830	1,750	2,713	2,340	1,365	1,640	25,105	8,058	5,397
Employee Stock Ownership Plan expense	953	1,500	1,500	1,500	1,000	1,000	1,000	1,000	5,453	4,000	4,000
Other selling, general and administrative expenses	5,170	6,068	7,506	6,723	3,841	2,855	2,713	2,867	25,466	12,276	12,158
Contingent consideration revaluation		(9,598)	2,674	869	(21)				(6,054)	(21)
Income (loss) from operations	(4,612)	13,245	(16,652)	6,060	1,585	5,687	9,532	5,364	(1,958)	22,169	9,426
Interest expense	(918)	(987)	(1,991)	(2,832)	(1,274)	(846)	(853)	(906)	(6,728)	(3,879)	(4,180)
Loss on extinguishment of debt			(154)		(226)		(588)		(154)	(814)
Income (loss) before taxes	(5,530)	12,258	(18,797)	3,228	85	4,841	8,091	4,458	(8,840)	17,476	5,246
Income tax benefit	(3,857)	2,512	(3,513)	769	(505)	17		29	(4,088)	(459)	0
Net income (loss) and comprehensive income (loss)	(1,673)	9,746	(15,284)	2,459	590	4,824	8,091	4,430	(4,753)	17,935	5,246
Earnings (loss) per share
Net income (loss) available to shareholders	$ (1,673)	$ 9,746	$ (15,284)	$ 2,459	$ 590	$ 4,824	$ 8,091	$ 4,430	$ (4,753)	$ 17,935	$ 5,246
Basic and diluted earnings (loss) per share	$ (0.08)	$ 0.49	$ (0.91)	$ 0.18	$ 0.04	$ 0.36	$ 0.56	$ 0.31	$ (0.27)	$ 1.29	$ 0.37
Basic and diluted weighted average shares outstanding	19,711,921	19,740,296	16,799,915	13,443,484	13,443,524	13,453,285	14,341,538	14,177,317	17,447,464	13,891,301	14,341,538
Tax-adjusted pro forma information
Net income (loss) available to shareholders	$ (1,673)	$ 9,746	$ (15,284)	$ 2,459	$ 590	$ 4,824	$ 8,091	$ 4,430	$ (4,753)	$ 17,935	$ 5,246
Pro forma provision for income taxes			103	70	175	1,254	2,104	1,130	173	4,663
Pro forma net income (loss)	$ (1,673)	$ 9,746	$ (15,387)	$ 2,389	$ 415	$ 3,570	$ 5,987	$ 3,300	$ (4,926)	$ 13,272	$ 5,246
Pro forma basic and diluted earnings (loss) per share	$ (0.08)	$ 0.49	$ (0.92)	$ 0.18	$ 0.03	$ 0.27	$ 0.42	$ 0.23	$ (0.28)	$ 0.96	$ 0.37
Basic and diluted weighted average shares outstanding	19,711,921	19,740,296	16,799,915	13,443,484	13,443,524	13,453,285	14,341,538	14,177,317	17,447,464	13,891,301	14,341,538

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical)	May 13, 2019	Dec. 31, 2019
Effective income tax rate reconciliation		26.00%
May 2019 IPO [Member]
Dividend stock split conversion ratio	133434.00%

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)		$ (4,753)	$ 17,935	$ 5,246
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation		22,296	16,372	16,975
Amortization		10,706	4,096	3,756
Stock-based compensation expense		3,486
Costs recognized on step-up of acquired inventory		395	583
Contingent consideration revaluation		(6,054)	(21)
Gain on disposal of property, plant and equipment		(62)	(177)	(23)
Deferred compensation and long-term incentive		11,598	4,466	1,000
Loss (gain) on extinguishment or forgiveness of debt		(367)	814
Provision for doubtful accounts			(48)
Non-cash adjustments		(13)	218
Changes in operating assets and liabilities – net of effects of acquisition:
Accounts receivable		11,853	1,042	2,570
Inventories		8,886	(6,873)	(2,480)
Tooling in progress		729	489	(481)
Prepaids and other current assets		(1,358)	(4,425)	(106)
Accounts payable		(11,010)	834	2,083
Deferred income taxes		(5,992)
Accrued liabilities, excluding long-term incentive		(6,938)	1,410	2,261
Net cash provided by operating activities		33,402	36,715	30,801
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property, plant and equipment		(25,797)	(17,879)	(11,259)
Proceeds from sale of property, plant and equipment		76	10	24
Acquisitions, net of cash acquired		(2,369)	(114,700)
Net cash used in investing activities		(28,090)	(132,569)	(11,235)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from bank revolving credit notes		442,154	257,428	132,473
Payments on bank revolving credit notes		(429,211)	(228,137)	(133,882)
Proceeds from issuance of other long-term debt			167,094
Repayments of other long-term debt		(120,046)	(87,389)	(9,099)
Deferred financing costs			(2,173)	(412)
Proceeds from IPO, net		101,763
Purchase of treasury stock		(2,591)	(7,833)	(8,713)
Payments on capital leases		(469)	(123)
Net cash provided by (used in) financing activities		(8,400)	98,867	(19,633)
Net increase (decrease) in cash and cash equivalents		(3,088)	3,013	(67)
Cash and cash equivalents, beginning of year		3,089	76	143
Cash and cash equivalents, end of year		1	3,089	76
Supplemental disclosure of cash flow information:
Cash paid for interest		6,629	4,117	4,305
In conjunction with the DMP acquisition, fair value of assets acquired and liabilities assumed were as followed:
Fair value of assets acquired, net of cash acquired	[1]		167,781
Liabilities assumed	[1]		(53,081)
Cash paid for acquisition, net of cash acquired	[1]		114,700
Non-cash construction in progress in accounts payable		$ 2,809	$ 1,240	$ 186
[1]	2019 relate to net working capital true-ups

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity - 12 months ended Dec. 31, 2019 - USD ($) shares in Thousands, $ in Thousands	Total	Additional Paid-in Capital [Member]	Treasury Shares [Member]	Retained Earnings [Member]
Beginning, Balance at Dec. 31, 2018
Transfer from Temporary Equity (see Note 19)	105,845	133,806	(57,659)	29,698
Share issuance – IPO	$ 101,763	101,763
Cancellation of Treasury Stock		(55,369)	$ 55,369
Share repurchases	(2,592)		(2,592)
Stock-based compensation	$ 3,486	3,486
Net loss post IPO	(7,609)			(7,609)
Ending, Balance at Dec. 31, 2019	$ 200,895	$ 183,687	$ (4,882)	$ 22,089

Nature of business and summary

Nature of business and summary of significant accounting policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Nature of business and summary of significant accounting policies	Note 1. Nature of business and summary of significant accounting policies Mayville Engineering Company, Inc. and subsidiaries (MEC, the Company, we, our, us or similar terms) 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 vehicle, construction, powersports, agriculture, military and other end markets. Founded in 1945 and headquartered in Mayville, Wisconsin, we are a leading Tier I U.S. supplier of highly engineered components to original equipment manufacturers (OEM) customers with leading positions in their respective markets. The Company operates 20 facilities located in Arkansas, Michigan, Mississippi, Ohio, Pennsylvania, South Carolina, Virginia, and Wisconsin. Our engineering expertise and technical know-how allow us to add value through every product redevelopment cycle (generally every three to five years for our customers). In December 1985, the Company formed the Mayville Engineering Company, Inc. Employee Stock Ownership Plan (ESOP). The ESOP is a tax qualified retirement plan and is designed to invest primarily in the Company’s common stock which is held in a Trust. From January 2003 until the Company’s initial public offering of its common stock (IPO) in May 2019, the ESOP owned 100% of the Company’s outstanding shares of common stock which have been fully allocated to active or retired eligible employees. Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). They include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts and disclosures. Accordingly, actual results could differ from those estimates. Cash and cash equivalents The Company considers all highly-liquid investments purchased with original maturities of 90 days or less to be cash and cash equivalents. Concentration of credit risk Financial instruments that potentially subject the Company to credit risk consist principally of bank balances above the Federal Deposit Insurance Corporation (FDIC) insurability limits of $250 per official custodian. The Company has not experienced any losses on these accounts and management believes the Company is not exposed to any significant credit risk on cash. Accounts receivable Accounts receivable are generally uncollateralized customer obligations due under normal trade terms requiring payment within 30 to 60 days from the invoice date. Management periodically reviews past due balances and established an allowance for doubtful accounts of approximately $526 and $801 as of December 31, 2019 and 2018, respectively, for probable uncollectible amounts based on its assessment of the current status of individual accounts. The estimated valuation allowance results in a charge to earnings and the accounts are written-off through a charge to the valuation allowance and a credit to accounts receivable after the Company has used all reasonable collection efforts. Inventories Inventories are stated at the lower of cost, determined on the first-in, first-out method (FIFO), and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. Work-in-process and finished goods are valued at production cost consisting of material, labor and overhead. The Company maintains a reserve for obsolete and slow-moving inventory which is based upon the aging of current inventory as well as assumptions on future demand and market conditions. Tooling in progress The Company has agreements with its customers to provide production tooling which will be used to produce specific parts for its customers. The costs to design, engineer, and manufacture the tooling are charged to tooling in progress as incurred and upon completion are sold to customers. The Company may also provide production tooling that is not sold to customers but is capitalized in property, plant and equipment. To the extent that estimated costs exceed expected reimbursement from the customer, the Company recognizes a loss. Tooling in progress was $1,589 and $2,318 as of December 31, 2019 and 2018, respectively. Property, plant and equipment Property, plant and equipment are stated at cost. Expenditures for additions and improvements are capitalized while replacements, maintenance and repairs which do not improve or extend the lives of the respective assets are expensed as incurred. Properties sold, or otherwise disposed of, are removed from the property accounts, with gains or losses on disposal credited or charged to the results of operations. Depreciation is provided over the estimated useful lives of the respective assets, using the straight-line depreciation method for financial reporting purposes and begins when the asset is placed into service. Depreciation expense for the twelve months ended December 31, 2019, 2018 and 2017 was $22,296, $16,372 and $16,975, respectively, and is included in cost of sales on the consolidated statements of comprehensive income. Business combinations The Company accounts for all business combinations in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 805, Business Combinations. In connection with a business combination, the acquiring company must allocate the cost of the acquisition to assets acquired and liabilities assumed based on fair values as of the acquisition date. Any excess or shortage of amounts assigned to assets and liabilities over or under the purchase price is recorded as a gain on bargain purchase or goodwill. Transaction costs associated with acquisitions are expensed as incurred within selling, general and administrative expenses. Goodwill We test goodwill for impairment annually, or more frequently if triggering events occur indicating that there may be an impairment. We have recorded goodwill and perform testing for potential goodwill impairment at a reporting unit level. A reporting unit is an operating segment, or a business unit one level below an operating segment for which discrete financial information is available, and for which management regularly reviews the operating results. Additionally, components within an operating segment can be aggregated as a single reporting unit if they have similar economic characteristics. We have performed testing on each of our reporting units which contain goodwill. We determine the fair value of our reporting units using multiple valuation methodologies, relying largely on an income approach but also incorporating value indicators from a market approach. Under the income approach, we calculate the fair value of a reporting unit based on the present value of estimated future cash flows. The income approach is dependent on several key management assumptions, including estimates of future sales, gross margins, operating costs, interest expense, income tax rates, capital expenditures, changes in working capital requirements and the weighted average cost of capital or the discount rate. Discount rate assumptions include an assessment of the risk inherent in the future cash flows of the reporting unit. Expected cash flows used under the income approach are developed in conjunction with our budgeting and forecasting process. Under the market approach, we estimate fair value of the reporting units using EBITDA multiples. The multiples are derived from comparable publicly traded companies with similar operating and investment characteristics as the respective reporting units. During the fourth fiscal quarters of 2019 and 2018, we performed our annual impairment assessments of goodwill, which did not indicate an impairment existed. For the twelve months ended December 31, 2018 we had two reporting units, DMP and MEC. The DMP reporting unit was acquired on December 14, 2018 and had preliminarily estimated goodwill of $29.2 million as of December 31, 2018. For the 18-day period from December 14 through December 31, 2018, DMP’s actual results of operations were above estimates utilized to determine the preliminary purchase price allocation. As a result, the fair value of the DMP reporting unit at December 31, 2018 is nominally above its carrying value. At December 31, 2018, the MEC reporting unit had goodwill with a carrying amount of approximately $40.2 million. The fair value of the MEC reporting unit substantially exceeded carrying value for 2018. For the twelve months ended December 31, 2019, we concluded that the DMP and MEC reporting units were integrated into one reporting unit. At December 31, 2019, the reporting unit had goodwill with a carrying amount of approximately $71.5 million. The fair value of this reporting unit substantially exceeded the carrying value for 2019. Changes to management assumptions and estimates utilized in the income and market approaches could negatively impact the fair value conclusions for our reporting units resulting in goodwill impairment. All key assumptions and valuations are determined by and are the responsibility of management. The factors used in the impairment analysis are inherently subject to uncertainty. We believe that the estimates and assumptions are reasonable to determine the fair value of our reporting units, however, if actual results are not consistent with these estimates and assumptions, goodwill and other intangible assets may be overstated which could trigger an impairment charge. Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable and long-term debt. The carrying amount of all significant financial instruments approximates fair value due to either the short maturity or the existence of variable interest rates that approximate prevailing market rates. Cash and cash equivalents, accounts receivable and accounts payable are classified as Level 1 fair value inputs as further described in Note 17. Long-term debt is classified as a Level 1 and Level 2 fair value input. Impairment of long-lived assets When events or conditions warrant, the Company evaluates the recoverability of long-lived assets and considers whether these assets are impaired. The Company assesses the recoverability of these assets based on several factors, including management’s intention with respect to these assets and their projected undiscounted cash flows. If projected undiscounted cash flows are less than the carrying amount of the respective assets, the Company adjusts the carrying amounts of such assets to their estimated fair value. To the extent that the carrying value of the net assets of a reportable unit is greater than the estimated fair value, the Company may be required to record impairment charges. Deferred financing costs Loan issuance costs and discounts are capitalized upon the issuance of long-term debt and amortized over the life of the related debt and are presented as a reduction of the associated long-term debt on the consolidated balance sheets. Loan issuance costs associated with revolving debt arrangements are presented as a component of other assets. Loan issuance costs incurred in connection with revolving debt arrangements are amortized using the straight-line method over the life of the credit agreement. Loan issuance costs and discounts incurred in connection with term debt are amortized using the effective interest method. Amortization of deferred loan issuance costs and discounts are included in interest expense. During 2019, 2018 and 2017 the Company recorded $142, $2,173 and $412, respectively of deferred financing costs associated with its long-term debt and line of credit arrangements. Amortization expense associated with the deferred debt issuance costs and discounts in 2019, 2018 and 2017 was approximately $381, $198 and $249. Accumulated amortization was approximately $474, $114 and $619 as of December 31, 2019, 2018 and 2017, respectively. Amendments made to existing debt in 2019, 2018 and 2017 resulted in the write-offs of $154, $814 and zero, respectively of unamortized costs associated with the debt that was replaced. Revenue recognition The Company adopted ASC 606 January 1, 2019, where the Company recognizes revenue for the transfer of goods or services to a customer in an amount that reflects the consideration it expects to receive in exchange for those goods or services. When goods are shipped, the customer takes ownership at shipment, and this is when control transfers. Sales are supported by documentation such as supply agreements and purchase order, which specify certain terms and conditions including product specifications, quantities, fixed prices, delivery dates and payments terms. Revenue related to services is recognized in the period services are performed, thus the Company recognizes revenue at a point in time. There are many customers where the Company designs, engineers and builds production tooling, which is purchased by the customer. Revenue is recognized when the tooling is completed, the customer signs off the product through the Product Part Approval Process (PPAP) and the tool is placed into service. Revenue related to production tooling is recognized as a point in time when it meets the PPAP criteria. The Company offers certain customers discounts for early payments. These discounts are recorded against net sales in the consolidated statement of comprehensive income and accounts receivable in the consolidated balance sheet. The Company does not offer any other customer incentives, rebates or allowances. Shipping and handling The Company expenses shipping and handling costs as incurred. These costs are generally comprised of salaries and wages, shipping supplies and warehouse costs. These costs are included in cost of sales on the consolidated statements of comprehensive income. The Company does not charge customers nor recognize revenue for shipping and handling. The Company’s OEM customers arrange and pay the freight for delivery. Advertising The Company expenses the costs of advertising when incurred. Advertising expense was approximately $110, $116 and $157 for the twelve months ended December 31, 2019, 2018 and 2017, respectively. Advertising costs are charged to selling, general and administrative expenses. Income Taxes Income taxes and uncertain tax positions are accounted for in accordance with ASC 740, “Accounting for Income Taxes”. Deferred income taxes are provided for the differences between the bases of assets and liabilities for financial reporting and income tax purposes. The Company measures deferred tax assets and liabilities using enacted tax rates in effect for the years in which the differences are expected to reverse and recognizes the effect of a change in enacted rates in the period of enactment. Tax positions meeting the more-likely-than-not recognition threshold are measured pursuant to the guidance set forth in ASC 740. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. See Note 11 “Income Taxes” of these Notes to Consolidated Financial Statements for further discussion. Earnings per share The Company computes basic earnings (loss) per share by dividing net income (loss) available to shareholders by the actual weighted average number of common shares outstanding for the reporting period. The Company does not have any potentially dilutive convertible securities. As a result, basic and diluted earnings per share for the Company are the same. Treasury Stock Treasury stock purchases are accounted for under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock. Subsequent reissuance of shares to the ESOP are recorded as a reduction to treasury stock and as ESOP expense in the consolidated statement of comprehensive income. Recent Accounting Pronouncements In May 2014, FASB issued Accounting Standard Update (ASU) 2014-09, Revenue from Contracts with Customers (ASU 2014-09), and issued subsequent amendments to the initial guidance within ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (ASU 2016-08) issued in March 2016, ASU 2016-10, Revenue from Contracts with Customers, Identifying Performance Obligations and Licensing (ASU 2016-10) issued in April 2016, ASU 2016-12, Revenue from Contracts with Customers, Narrow-Scope Improvements and Practical Expedients (ASU 2016-12) issued in May 2016 and ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers (ASU 2016-20) issued in December 2016 (ASU 2014-09, ASU 2016-08, ASU 2016-10, ASU 2016-12 and ASU 2016-20 collectively “Topic 606”). Topic 606 provides a comprehensive revenue recognition model requiring companies to recognize revenue for the transfer of goods or services to a customer in an amount that reflects the consideration it expects to receive in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In July 2015, the FASB voted to defer the effective date of ASU 2014-09 by one year, and therefore the standard is effective for the Company's annual and interim periods beginning after December 15, 2019. Effective January 1, 2019, the Company implemented the new standard using a five-step model specified in the guidance using the modified retrospective method. The implementation did not have a material impact on the consolidated financial statements and there was no adjustment to retained earnings from implementation. In February 2016, the FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments, which establishes ASC 326, Financial Instruments – Credit Losses. The ASU revises the measurement of credit losses for financial assets measured at amortized cost from an incurred loss methodology to an expected loss methodology. The ASU affects trade receivables, debt securities, net investment in leases, and most other financial assets that represent a right to receive cash. Additional disclosures about significant estimates and credit quality are also required. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses. This ASU clarifies that receivables from operating leases are accounted for using the lease guidance and not as financial instruments. In January 2017, the FASB issued ASU 2017-01, Clarifying the Definition of a Business, which narrows the application of when an integrated set of assets and activities is considered a business and provides a framework to assist entities in evaluating whether both an input and a substantive process are present to be considered a business. It is expected that the new guidance will reduce the number of transactions that would need to be further evaluated and accounted for as a business. For public companies, this guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years. For as long as the Company remains an EGC, the new guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within annual periods beginning after December 15, 2019. Early adoption is permitted. The Company is evaluating the potential impact of adopting this guidance on the consolidated financial statements. In January 2017, the FASB issued ASU, 2017-04, Simplifying the Test for Goodwill Impairment, which simplifies the subsequent measurement of goodwill by removing the requirement to perform a hypothetical purchase price allocation to compute the implied fair value of goodwill to measure impairment. Instead, any goodwill impairment will equal the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Further, the guidance eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. For public companies, this guidance is effective for annual or any interim goodwill impairment test in annual reporting periods beginning after December 15, 2020. For as long as the Company remains an EGC, the new guidance is effective for any annual or interim goodwill impairment test in annual reporting periods beginning after December 15, 2021. The adoption of this guidance is not expected to have a material impact on the consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement (ASU 2018-13) to improve the effectiveness of fair value measurement disclosures. The amendments in this Update modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement based on the concepts in FASB Concept Statement, including the consideration of costs and benefits. The amendments in this Update are effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption of this guidance is permitted for removed or modified disclosures upon issuance of this Update while a delayed adoption of the additional disclosures is allowed until the effective date. The Company is evaluating the impact of this standard on its financial statements.

IPO

IPO	12 Months Ended
	Dec. 31, 2019
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.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisition	Note 3. Acquisition On December 14, 2018, the Company acquired Defiance Metal Products Co. (DMP), a full-service metal fabricator and contract manufacturer with two facilities in Defiance, OH, one in Heber Springs, AR, and one in Bedford, PA. The Company acquired DMP for $117,068, net of cash received, plus potential contingent consideration of up to $10,000. The Company would have paid DMP’s previous shareholders $7,500 if DMP generated $19,748 of EBITDA, as defined by the stock purchase agreement, over the twelve-month period ended September 30, 2019. In addition, the Company would have paid one dollar for each additional dollar of EBITDA in excess of $19,748 generated over this period; however, in no event would the total have payment exceeded $10,000. The estimated fair values of assets acquired, and liabilities assumed are as follows: Opening Balance Sheet Allocation Cash consideration at acquisition date, net of cash received $ 114,700 Cash consideration for net working capital adjustment 2,368 Contingent consideration fair value as of acquisition date 6,076 Total purchase price $ 123,144 Accounts receivable, net $ 26,927 Tooling in progress 1,318 Inventory, net 13,237 Property, plant and equipment, net 30,017 Other assets, net of cash 416 Intangible assets Trade name 14,780 Customer relationships 44,550 Non-compete 8,800 Goodwill 31,333 Total assets acquired 171,378 Deferred income taxes 20,221 Other liabilities 28,014 Net assets acquired $ 123,144 The aggregate purchase price has been allocated to the assets acquired and liabilities assumed based on their fair values as of the acquisition date. The excess purchase price over the estimated fair value of net tangible assets acquired was allocated to identifiable intangible assets and goodwill. The Company engaged a reputable independent third party to assist with the identification and valuation of the intangible assets. Management made significant estimates and assumptions when determining the fair value of assets acquired and liabilities assumed. These estimates include, but are not limited to, discount rates, projected future net sales, projected future expected cash flows, useful lives, attrition rates, royalty rates, and growth rates. These measures are based on significant Level 3 inputs (see Note 17) not observable in the market. In connection with the DMP acquisition, inventory was valued at its estimated fair value which is defined as expected sales price less costs to sell. The valuation resulted in an inventory fair value step-up of $978. This amount was amortized based on inventory turns, with the amortization resulting in a reduction of inventory and an expense reflected in cost of sales on the Consolidated Statement of Comprehensive Income (Loss). The Company amortized $395 and $583 of the inventory fair value step-up during the twelve months ended and December 31, 2019 and 2018 respectively. The Company recorded $14,780 of trade name intangible assets with an estimated useful life of 10 years, $44,550 of customer relationship intangible assets with an estimated useful life of 12 years, and $8,800 of non-compete agreements with an estimated useful life of 5 years. These intangibles are amortized on a straight-line basis. The Company believes that the estimated useful lives and the straight-line amortization methodology most appropriately reflect when and how the Company expects to benefit from the identifiable intangible assets. Amortization expense related to these intangible assets is reflected in amortization of intangible expenses on the Consolidated Statement of Comprehensive Income (Loss). The Company also estimated and recorded the fair value of the contingent consideration payable to be $6,076 as of the acquisition date. The Company remeasured this liability utilizing a Monte Carlo valuation model through the conclusion of the earnout period, September 30, 2019, with the change in value resulting in income or expense and reflected in the Contingent Consideration Revaluation line item on the Consolidated Statement of Comprehensive Income (Loss). The primary inputs utilized in the Monte Carlo valuation model include actual and projected EBITDA along with a discount rate. Contingent consideration payable was revalued to $0, $9,598, $6,924, and $6,054 as of September 30, 2019, June 30, 2019, March 31, 2019 and December 31, 2018, respectively. The change between these balances resulted in (income)/expense of ($9,598), $2,674, $869, and ($21) for the three months ended September 30, 2019, June 30, 2019, March 31, 2019, and the twelve months ended December 31, 2018, respectively. Based on our calculations as of September 30, 2019, and as agreed to by DMP’s former shareholders, DMP’s EBITDA fell short of the $19,748 contingent consideration threshold. As a result, and in accordance with GAAP, the contingent consideration balance of $9,598 was reduced to zero resulting in an adjustment of $6,054 reflected in the Contingent Consideration Revaluation line item on the Consolidated Statements of Comprehensive Income (Loss) for the twelve months ended December 31, 2019. The purchase price of DMP exceeded the preliminary estimated fair value of identifiable net assets and accordingly, the difference was allocated to goodwill, which is not tax deductible. The Company believes that the information gathered to date provides a reasonable basis for estimating the fair values of assets acquired and liabilities assumed. As of December 31, 2019, the Company has finalized the estimates of assets and acquired liabilities assumed. Since its preliminary estimates, the Company adjusted the fair value on the opening balance sheet by increasing/(decreasing) accounts receivable by $27, inventory by $1,508, property plant and equipment by ($36), deferred income taxes by $1,097 and other liabilities by $31. In addition, the Company finalized the net working capital adjustment during the three month period ended June 30, 2019 resulting in an additional payout of $2,368 by the Company to the seller, bringing the Company’s acquisition of DMP to $117,068 in total cash paid, net of cash acquired. The offsetting entries of these adjustments was to goodwill. The DMP acquired entities accounted for $193,420 of net sales and $10,903 of net income for the twelve months ended December 31, 2019. Net income includes the contingent consideration fair value adjustments previously discussed. Pro Forma Financial Information (Unaudited): In accordance with ASC 805, the following unaudited pro forma combined results of operations have been prepared and presented to give effect to the DMP acquisition as if it had occurred on January 1, 2018, the beginning of the comparable period, applying certain assumptions and proforma adjustments. These proforma adjustments primarily relate to the depreciation expense on stepped-up fixed assets, amortization of identifiable intangible assets, costs of goods sold expense on the sale of stepped inventory, interest expense related to additional debt needed to fund the acquisition, and the tax impact of these adjustments. The unaudited pro forma consolidated results are provided for illustrative purposes only and are not indicative of the Company’s actual consolidated results of operations or consolidated financial position. The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the acquisition. The unaudited pro forma net income of $17,151 is $914 lower than the amount previously reported for the same pro forma period. The previously disclosed pro forma schedules were prepared in accordance with ASC 805 as if the DMP acquisition had occurred on January 1, 2017, the beginning of the first comparable period included in that filing. The difference in these assumed acquisition dates resulted in $914 of net expense being recorded in the proforma financials that were reflected in the previously disclosed 2017 proforma financials. The $914 is comprised of $978 of inventory fair value step-up amortization and $257 of loss on debt extinguishment offset by $260 of tax benefit of these items based on an assumed tax rate of 26%. Twelve Months Ended December 31, 2018 Net sales $ 523,721 Net income 17,151

Select balance sheet data

Select balance sheet data	12 Months Ended
	Dec. 31, 2019
Select Balance Sheet Data [Abstract]
Select balance sheet data	Note 4. Select balance sheet data Inventory Inventories as of December 31, 2019 and December 31, 2018 consist of: December 31, 2019 December 31, 2018 Finished goods and purchased parts $ 28,664 $ 32,589 Raw materials 10,834 12,329 Work-in-process 6,194 8,487 Total $ 45,692 $ 53,405 The change in inventory from $53,405 as of December 31, 2018 to $45,692 as of December 31, 2019 includes a $395 reduction related to the amortization of the DMP inventory fair value step-up. Property, plant and equipment Property, plant and equipment as of December 31, 2019 and December 31, 2018 consist of: Useful Lives Years* December 31, 2019 December 31, 2018 Land Indefinite $ 1,264 $ 1,264 Land improvements 15-39 3,169 3,169 Building and building improvements 15-39 58,021 55,269 Machinery, equipment and tooling 3-10 204,248 182,045 Vehicles 5 3,738 3,613 Office furniture and fixtures 3-7 15,469 14,253 Construction in progress N/A 3,154 6,786 Total property, plant and equipment, gross 289,063 266,399 Less accumulated depreciation 164,000 142,516 Total property, plant and equipment, net $ 125,063 $ 123,883 Goodwill Changes in goodwill between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 69,437 DMP purchase accounting adjustments, net (270 ) DMP net working capital true-up 2,368 Balance as of December 31, 2019 $ 71,535 Intangible Assets The following is a listing of intangible assets, the useful lives in years (amortization period) and accumulated amortization as of December 31, 2019 and December 31, 2018: Useful Lives Years December 31, 2019 December 31, 2018 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 (33,582 ) (22,876 ) Total amortizable intangible assets, net 68,362 79,068 Non-amortizable brand name 3,811 3,811 Total intangible assets, net $ 72,173 $ 82,879 Non-amortizable brand name is tested annually for impairment. Changes in intangible assets between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 82,879 Amortization expense (10,706 ) Balance as of December 31, 2019 $ 72,173 Amortization expense was $10,706, $4,096 and $3,756 for the twelve months ended December 31, 2019, 2018 and 2017 respectively. Future amortization expense is expected to be $10,706, $10,706, $6,952, $6,865 and $5,192 for the twelve months ended December 31, 2020, 2021, 2022, 2023 and 2024, respectively.

Bank revolving credit notes

Bank revolving credit notes	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Bank revolving credit notes	Note 5. 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 Agent). The A&R Credit Agreement provides for $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 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 December 31, 2019, our interest coverage ratio was 7.42 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 December 31, 2019, our consolidated total leverage ratio was 1.39 to 1.00. Prior to September 26, 2019, the Company maintained a credit agreement providing for $90,000 borrowing capacity through a revolving credit note. Under both agreements, interest is payable monthly at the adjusted London Interbank Offered Rate plus an applicable margin based on the current funded indebtedness to adjusted EBITDA ratio. The interest rate was 3.25% and 4.69% as of December 31, 2019 and December 31, 2018, respectively. Additionally, both agreements have a fee on the average daily unused portion of the aggregate unused revolving commitments. This fee was 0.20% as of December 31, 2019 and December 31, 2018. The Company was in compliance with all financial covenants of its credit agreements as of December 31, 2019 and December 31, 2018. The amount borrowed on the revolving credit notes was $72,572 and $59,629 as of December 31, 2019 and December 31, 2018, respectively.

Other long-term debt

Other long-term debt	12 Months Ended
	Dec. 31, 2019
Other Longterm Debt [Abstract]
Other long-term debt	Note 6. Other long-term debt Prior to September 26, 2019, the Company maintained a facility financing package with borrowings of $95,000 and a maturity date of December 14, 2023 and a strategic capital loan with borrowings of $25,000 and a maturity date of June 14, 2024. As of September 26, 2019, all long-term debt was paid off in connection with entering into the A&R Credit Agreement. Government loan balances include forgiveness clauses based upon capital spending and headcount increases at the noted manufacturing locations. As previously disclosed, the Company completed its IPO in May 2019. Proceeds from the IPO were used to pay down debt including $43,000 pay down of the prior Term A loan and $25,000 pay-off of the prior strategic capital loan. In June 2019, the Company received written notification that the $521 balance remaining of the Smyth County, Virginia loan was forgiven. Due to the nature of the requirements to obtain forgiveness, the gain associated with the forgiveness is reflected in cost of sales on the Consolidated Statement of Comprehensive Income (Loss). On September 26, 2019, the Company entered into the A&R Credit Agreement resulting in the payoff of the real estate term loan and the Term A loan through the A&R Credit Agreement. In December 2019, the Company paid off the Wisconsin Economic Development Corporate loan. Other long-term debt as of December 31, 2019 and December 31, 2018 consisted of the following: December 31, 2019 December 31, 2018 Interest Rate Balance Interest Rate Balance Term A loans – 2018 financing package N/A $ — 4.69 % $ 69,000 Real estate term loan – 2018 financing package N/A — 4.69 % 26,000 Strategic capital loan N/A — 11.78 % 25,000 Wisconsin Economic Development Corporate (Neillsville) N/A — 2.00 % 406 Smyth County, Virginia N/A — 0.00 % 700 Total principal outstanding — 121,106 Less: Unamortized debt issuance costs — (825 ) Less: Current maturities — (8,606 ) Long-term debt, less current maturities, net $ — $ 111,675 The Company was in compliance with all financial covenants of its long-term debt agreements as of December 31, 2019.

Capital lease obligation

Capital lease obligation	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Capital lease obligation	Note 7. Capital lease obligation Capital leases consist of equipment with a capitalized cost of $3,825 and accumulated depreciation of $598 at December 31, 2019. Depreciation of $503 was recognized on the capital lease assets during the twelve months ended December 31, 2019. Non-cash capital lease transactions amounted to $1,776, $2,051 and zero, for the twelve months ended December 31, 2019, 2018 and 2017, respectively. Future minimum lease payments required under the lease are as follows: Year ending December 31, 2020 $ 734 2021 734 2022 734 2023 734 2024 514 Thereafter 226 Total 3,676 Less payment amount allocated to interest 392 Present value of capital lease obligation $ 3,285 Current portion of capital lease obligation 598 Long-term portion of capital lease obligation 2,687 Total capital lease obligation $ 3,285

Operating lease obligation

Operating lease obligation	12 Months Ended
	Dec. 31, 2019
Lessee Disclosure [Abstract]
Operating lease obligation	Note 8. Operating lease obligation Operating leases relate to property, plant and equipment. Future minimum lease payments required under the lease are as follows: Year ending December 31, 2020 $ 3,402 2021 2,725 2022 1,923 2023 1,792 2024 830 Thereafter 2,094 Total $ 12,766 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 times through December 2028. Total rent expense under the arrangements was approximately $4,801, $2,052 and $1,856 for the twelve months ended December 31, 2019, 2018, and 2017, respectively.

Employee stock ownership plan

Employee stock ownership plan	12 Months Ended
	Dec. 31, 2019
Employee Stock Ownership Plan E S O P Shares In E S O P [Abstract]
Employee stock ownership plan	Note 9. Employee stock ownership plan Under the ESOP, the Company makes annual contributions to the trust for the benefit of eligible employees in the form of cash or shares of the Company. The annual contribution is discretionary except that it must be at least 3% of the compensation for all safe harbor participants for the plan year. For the twelve months ended December 31, 2019, 2018 and 2017, the Company’s ESOP expense amounted to $5,453, $4,000 and $4,000, 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. During the twelve months ended December 31, 2019 the ESOP did not acquire any shares from withdrawing participants. As of December 31, 2019, and December 31, 2018, the ESOP shares consisted of 11,790,113 and 13,443,484 in allocated shares, respectively after giving effect to the issuance of a stock dividend of approximately 1,334.34-for-1 related to the Company’s May 2019 IPO. 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. Based on the mandatory redemption of these shares, they represented temporary equity on the consolidated balance sheets for periods prior to the IPO. The total estimated fair value of all allocated shares subject to this repurchase obligation approximated $133,806 as of December 31, 2018. The estimated fair value as of December 31, 2018 was based on the most recent available appraisals of the common stock which was approximately $9.95 per share after giving effect to the issuance of a stock dividend of approximately 1,334.34-for-1 related to the Company’s May 2019 IPO. Subsequent to the IPO, ESOP shares are sold in the public market.

Retirement plans

Retirement plans	12 Months Ended
	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Retirement Plans	Note 10. Retirement plans The Company established the Mayville Engineering Company, Inc. 401(k) Plan (the 401(k) Plan) covering 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 authorized discretionary profit sharing contributions of zero, $696 and $671 for the twelve months ended December 31, 2019, 2018 and 2017, respectively, that are funded in the subsequent years.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income taxes	Note 11. Income taxes Income taxes are included in the consolidated statements of income at December 31, 2019 and 2018 as below: (in thousands) December 31, 2019 December 31, 2018 Current income tax expense (benefit) U.S Federal $ 401 $ (126 ) State 1,544 614 Total 1,945 488 Deferred income tax benefit U.S Federal (4,197 ) (793 ) State (1,836 ) (154 ) Total (6,033 ) (947 ) Total income tax benefit $ (4,088 ) $ (459 ) A reconciliation of the statutory federal income tax expense to the income tax expense from continuing operations provided at December 31, 2019 and 2018, is as follows: (in thousands) December 31, 2019 December 31, 2018 Income tax expense at the federal statutory rate - 21% $ (1,854 ) $ (388 ) State and local income taxes - net of federal income tax benefits (58 ) (61 ) Compensation deduction limitation - section 162(m) adjustment 357 — Income taxed by shareholder before IPO (867 ) — Other - perms 77 171 Transaction Costs 607 — Change in tax status (2,355 ) — Tax credits generated (254 ) — Other misc. tax 259 (181 ) Total income tax benefit $ (4,088 ) $ (459 ) Effective tax rate 47.5 % -2.5 % The Company’s legacy business converted to a C Corporation on May 9, 2019. Previous to this date, the legacy business was an S Corporation where the tax burden was born by the shareholders, therefore income tax expense for December 31, 2017 was zero. The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities are presented below: (in thousands) December 31, 2019 December 31, 2018 Deferred tax assets: Deferred compensation $ 8,645 $ 226 Inventory adjustments 1,837 — Accrued expenses 211 — Credits 279 — Net operating loss 3,120 949 Other — 288 Total deferred tax assets 14,092 1,464 Deferred tax liabilities: Property, plant and equipment 8,354 4,379 Intangibles 19,305 16,034 Inventory adjustment — 175 Other 622 — Total deferred tax liabilities 28,281 20,587 Valuation allowance — — Net deferred tax liability $ (14,188 ) $ (19,123 ) Consolidated federal NOL’s are $13,827 and do not expire. In addition, consolidated state NOL’s commence expire as follows: (in thousands) Amount Expire Commencing Illinois $ 2,141 2039 Uncertain Tax Positions 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 December 31, 2019. The Company does not anticipate that there will be a material change in the balance of the unrecognized tax benefits in the next twelve months. Any interest and penalties related to uncertain tax positions are recorded in income tax expense. There were no amounts recorded as tax expense for interest and penalties for the year ended December 31, 2019. The Company files income tax returns in the United States federal jurisdiction and in various state and local jurisdictions. Federal tax returns for tax years beginning January 1, 2016, and state tax returns beginning January 1, 2015, are open for examination.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Contingencies	Note 12. 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	12 Months Ended
	Dec. 31, 2019
Deferred Compensation Liability [Abstract]
Deferred compensation	Note 13. 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 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, the Company’s contributions, 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 twelve months ended December 31, 2019, 2018 and 2017, eligible employees elected to defer compensation of $1,269, $856 and $292, respectively. As of December 31, 2019, and December 31, 2018, the total amount accrued for all benefit years under this plan was $24,949 and $13,351, respectively, which is included within the deferred compensation and long-term incentive on the 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 twelve months ended December 31, 2019, 2018 and 2017 amounted to $10,476, $1,647 and $1,133, respectively. These expenses are included in profit sharing, bonuses and deferred compensation on the Consolidated Statements of Comprehensive Income (Loss).

Long-Term incentive plan

Long-Term incentive plan	12 Months Ended
	Dec. 31, 2019
Share Based Compensation [Abstract]
Long-Term incentive plan	Note 14. Long-Term incentive plan 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. 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 total amount accrued for all grant years under this plan was $1,846 at December 31, 2018. This amount is included within profit sharing and bonus on the Consolidated Balance Sheets. Total expense for the long-term incentive plan for the twelve months ended December 31, 2019, 2018 and 2017 amounted to $10,000, $1,712 and $134, respectively. These expenses are included in profit sharing, bonuses and deferred compensation on the Consolidated Statements of Comprehensive Income (Loss). The LTIP was terminated May 2019 in conjunction with the IPO, resulting in a payout approximating the accrued balance at December 31, 2018, and the expense incurred during 2019.

Self-Funded insurance

Self-Funded insurance	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Self-Funded insurance	Note 15. 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. The Company purchases reinsurance to limit the annual risk associated with their multiple medical plans. Under one plan, the Company purchases reinsurance to limit the annual risk per participant to $225 with no aggregate stop loss. Under another plan, the Company purchases reinsurance to limit the annual risk per participant to $200 and to limit the annual aggregate risk related to this contract which was approximately $19,208, $17,726 and $16,176 for the twelve months ended December 31, 2019, 2018 and 2017, respectively. An estimated accrued liability of approximately $1,316 and $1,730 was recorded as of December 31, 2019 and December 31, 2018, respectively, for estimated unpaid claims and is included within other current liabilities on the Consolidated Balance Sheets.

Segments

Segments	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segments	Note 16. Segments The Company applies the provisions of ASC Topic 280, Segment Reporting The Company does not earn revenues or have long-lived asset located in foreign countries. In accordance with the enterprise-wide disclosure requirements of ASC 280, the Company’s net sales from external customers by main product lines are as follows: Twelve Months Ended December 31, 2019 2018 2017 Outdoor sports $ 7,181 $ 6,862 $ 7,896 Fabrication 334,340 147,099 129,387 Performance structures 71,881 84,231 87,742 Tube 71,108 80,715 65,440 Tank 40,033 39,641 27,359 Total 524,544 358,550 317,824 Intercompany sales elimination (4,839 ) (4,024 ) (4,493 ) Total, net sales $ 519,704 $ 354,526 $ 313,331

Fair value of financial instrum

Fair value of financial instruments	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value of financial instruments	Note 17. 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 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 at Report Date Using Balance at December 31, 2018 (Level 1) (Level 2) (Level 3) Deferred compensation $ 13,351 $ — $ — $ 13,351 Contingent consideration payable 6,054 — — 6,054 Total $ 19,405 $ — $ — $ 19,405 Changes in liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 19,405 Contingent consideration revaluation (6,054 ) Deferred compensation adjustments 11,673 Payments (75 ) Transfer to level 1 and level 2 investments (24,949 ) Balance as of December 31, 2019 $ — 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. Prior to the IPO, deferrals were deemed to have been invested in the Company stock at a price equal to the share value on the deferral date. Considered Level 3 on the fair value hierarchy, the Company computed the fair value of its stock through the utilization of an independent third-party valuation specialist. For the period subsequent to the IPO, 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. In conjunction with the IPO, investment vehicle options were changed to Level 1 and Level 2 within the fair value hierarchy. The change in fair value is recorded in deferred compensation and long-term incentive liabilities on the Consolidated Balance Sheets and deferred compensation expense on the Consolidated Statements of Comprehensive Income (Loss). On December 14, 2018, the Company acquired DMP for $117,068, net of cash received plus potential contingent consideration of up to $10,000. The Company would have paid DMP’s previous shareholders an additional $7,500 if DMP generated $19,748 of EBITDA over the twelve-month period ended September 30, 2019. In addition, the Company would have paid one dollar for each additional dollar of EBITDA in excess of $19,748 generated over this period; however, in no event would have the total payment exceeded $10,000. The Company estimated and recorded the fair value of the contingent consideration payable of $6,076 as of the acquisition date. The Company remeasured this liability through the conclusion of the earnout period, September 30, 2019, with the change in value resulting in income or expense reflected in the Contingent Consideration Revaluation line item on the Consolidated Statement of Comprehensive Income (Loss). Contingent consideration payable was revalued to $0 as of December 31, 2019. Based on our calculations as of September 30, 2019, and as agreed to by DMP’s former shareholders, DMP’s EBITDA fell short of the $19,748 contingent consideration threshold. As a result, and in accordance with GAAP, the contingent consideration balance of $9,598 was reduced to zero resulting in a net gain of $6,054 in the Contingent Consideration line item on the Consolidated Statements of Comprehensive Income (Loss) for the twelve months ended December 31, 2019. 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.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2019
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 twelve months ended December 31, 2019. (in thousands) Contract Assets Contract Liabilities As of January 1, 2019 $ 2,318 $ 977 Net Activity (729 ) (63 ) As of December 31, 2019 $ 1,589 $ 914 Disaggregated Revenue The following table represents a disaggregation of revenue by product category: Twelve Months Ended December 31, 2019 2018 2017 Outdoor sports $ 7,181 $ 6,862 $ 7,896 Fabrication 334,340 147,099 129,387 Performance structures 71,881 84,231 87,742 Tube 71,108 80,715 65,440 Tank 40,033 39,641 27,359 Total 524,544 358,550 317,824 Intercompany sales elimination (4,839 ) (4,024 ) (4,493 ) Total, net sales $ 519,704 $ 354,526 $ 313,331

Temporary Equity

Temporary Equity	12 Months Ended
	Dec. 31, 2019
Temporary Equity [Abstract]
Temporary Equity	Note 19. Temporary Equity Prior to the IPO in May 2019, the Company’s common stock was considered redeemable under GAAP because of certain repurchase obligations related to the ESOP. As a result, all common shares were recorded as temporary equity (redeemable common shares) on the consolidated balance sheets at their redemption value as of the respective balance sheet dates. Retained earnings on the consolidated balance sheet was adjusted for the changes during the period in the current redemption value of redeemable common shares. 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 twelve months ended December 31, 2019, excluding net income for the period of April 1, 2019 through the date of the IPO. Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings Balance as of January 1, 2018 $ 125,042 $ (49,826 ) $ 17,671 Net Income 17,936 Purchase of treasury shares (11,833 ) Redistribution of Stockholders Share 4,000 Change in redemption value of outstanding redeemable common shares, net 8,764 (8,764 ) Balance as of December 31, 2018 $ 133,806 $ (57,659 ) $ 26,842 Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings Balance as of January 1, 2019 $ 133,806 $ (57,659 ) $ 26,842 Net income pre IPO — — 2,856 Transfer from temporary equity to common equity (133,806 ) 57,659 (29,698 ) Balance as of December 31, 2019 $ — $ — $ —

Common Equity

Common Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Common Equity	Note 20. 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 mentioned in Note 19, Temporary Equity As disclosed in Note 2, IPO On June 28, 2019, the Company cancelled 24,180,421 shares of common stock held in the Company’s treasury and returned those shares to the status of authorized but unissued shares of common stock.

Concentration of major customer

Concentration of major customers	12 Months Ended
	Dec. 31, 2019
Risks And Uncertainties [Abstract]
Concentration of major customers	Note 21. 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 Twelve Months Ended December 31, As of As of 2019 2018 2017 December 31, 2019 December 31, 2018 Customer A 15.1 % 22.6 % 20.2 % <10 % <10 % B 13.5 % 19.3 % 19.8 % <10 % <10 % C <10 % 17.4 % 14.7 % <10 % <10 % D 13.1 % <10 % <10 % <10 % 12.6 % E <10 % <10 % <10 % 13.5 % 10.2 % F <10 % <10 % <10 % 10.4 % <10 %

Stock based compensation

Stock based compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock based compensation	Note 22. Stock based compensation The Company recognizes stock-based compensation using the fair value provisions prescribed by ASC Topic 718, Compensation – Stock Compensation The Mayville Engineering Company, Inc. 2019 Omnibus Incentive Plan provides the Company the ability to provide monetary payments based on the value of its common stock, up to two million shares. In May 2019, we granted stock awards, including stock options and restricted stock units, to key employees and outside directors. These awards vest on the 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 fair value of each stock-based compensation award is established on the date of grant. There were no stock awards granted previous to those granted in May 2019. For grants of restricted stock units, the fair value is established based on the market price on the date of the grant. There were 331,436 restricted stock units granted in May 2019 at a fair value of $17/unit. The total fair value of these award grants was $3,600 and $2,034, with requisite service periods of 1- and 2-year periods, respectively. For grants of options, we use the Black-Scholes option pricing model to estimate the fair value of share-based payment awards. The determination of the fair value of share-based awards is affected by stock price and a number of assumptions. Our assumptions included expected volatility of 21.3%, expected risk free rate of 2.42%, exercise price of $17 per share, and a ten year period to exercise. Expected volatility was estimated with the use of peer public company data. There were 287,895 options granted in May 2019 at a fair value of $6.07/option. The total fair value of these award grants was $1,748. These options have a requisite service period of 2 years. The Company recognized $3,486 of stock-based compensation expense for the twelve months ended December 31, 2019. Forfeitures during the year included 14,416 of options and 5,148 of restricted stock units. There were no option exercises or expirations during the twelve months ended December 31, 2019. There was $3,720 of unrecognized stock-based compensation expense as of December 31, 2019.

Valuation and qualifying accoun

Valuation and qualifying accounts	12 Months Ended
	Dec. 31, 2019
Valuation And Qualifying Accounts [Abstract]
Valuation and qualifying accounts	Note 23. Valuation and qualifying accounts Description Balance at beginning of period Additions Deductions Balance at end of period Year ended December 31, 2019 Allowance for doubtful accounts $ 801 $ 308 $ 583 $ 526 Year ended December 31, 2018 Allowance for doubtful accounts $ 308 $ 541 $ 48 $ 801

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent events	Note 24. Subsequent events The Company evaluated events and transactions for potential recognition or disclosure in the consolidated financial statements through March 2, 2020, the date on which the consolidated financial statements were available to be issued.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	Note 25. Quarterly results of operations (unaudited) The following tables present our unaudited quarterly results of operations for the eight quarters in 2019 and 2018. This unaudited information has been prepared on the same basis as our audited consolidated financial statements and includes all adjustments, consisting only of normal recurring adjustments, that we consider necessary for fair statement of our consolidated financial position and operating results for the quarters presented. This unaudited information should be read in conjunction with the consolidated financial statements and related notes included in Part II, Item 8 of this Annual Report on Form 10-K. Our operating results for any quarter are not necessarily indicative of results for any future quarters or for a full year. Q1 Q2 Q3 Q4 Full Year (in thousands, except share amounts and per share data) 2019 2019 2019 2019 2019 Net sales $ 143,732 $ 145,130 $ 128,511 $ 102,331 $ 519,704 Cost of sales 124,153 124,595 113,941 98,297 460,986 Amortization of intangibles 2,677 2,677 2,677 2,677 10,706 Profit sharing, bonuses, and deferred compensation 1,750 22,830 678 (153 ) 25,105 Employee Stock Ownership Plan expense 1,500 1,500 1,500 953 5,453 Other selling, general and administrative expenses 6,723 7,506 6,068 5,170 25,466 Contingent consideration revaluation 869 2,674 (9,598 ) — (6,054 ) Income (loss) from operations 6,060 (16,652 ) 13,245 (4,612 ) (1,958 ) Interest expense (2,832 ) (1,991 ) (987 ) (918 ) (6,728 ) Loss on extinguishment of debt — (154 ) — — (154 ) Income (loss) before taxes 3,228 (18,797 ) 12,258 (5,530 ) (8,840 ) Income tax benefit 769 (3,513 ) 2,512 (3,857 ) (4,088 ) Net income (loss) and comprehensive income (loss) $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Earnings (loss) per share Net income (loss) available to shareholders $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Basic and diluted earnings (loss) per share $ 0.18 $ (0.91 ) $ 0.49 $ (0.08 ) $ (0.27 ) Basic and diluted weighted average shares outstanding 13,443,484 16,799,915 19,740,296 19,711,921 17,447,464 Tax-adjusted pro forma information Net income (loss) available to shareholders $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Pro forma provision for income taxes 70 103 — — 173 Pro forma net income (loss) $ 2,389 $ (15,387 ) $ 9,746 $ (1,673 ) $ (4,926 ) Pro forma basic and diluted earnings (loss) per share $ 0.18 $ (0.92 ) $ 0.49 $ (0.08 ) $ (0.28 ) Basic and diluted weighted average shares outstanding 13,443,484 16,799,915 19,740,296 19,711,921 17,447,464 IPO occurred in Q2 of 2019. Q1 Q2 Q3 Q4 Full Year (in thousands, except share amounts and per share data) 2018 2018 2018 2018 2018 Net sales $ 87,221 $ 91,535 $ 84,338 $ 91,431 $ 354,526 Cost of sales 75,411 75,986 71,517 81,035 303,948 Amortization of intangibles 939 939 939 1,279 4,096 Profit sharing, bonuses, and deferred compensation 1,640 1,365 2,340 2,713 8,058 Employee Stock Ownership Plan expense 1,000 1,000 1,000 1,000 4,000 Other selling, general and administrative expenses 2,867 2,713 2,855 3,841 12,276 Contingent consideration revaluation — — — (21 ) (21 ) Income (loss) from operations 5,364 9,532 5,687 1,585 22,169 Interest expense (906 ) (853 ) (846 ) (1,274 ) (3,879 ) Loss on extinguishment of debt — (588 ) — (226 ) (814 ) Income (loss) before taxes 4,458 8,091 4,841 85 17,476 Income tax benefit 29 — 17 (505 ) (459 ) Net income (loss) and comprehensive income (loss) $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Earnings (loss) per share Net income (loss) available to shareholders $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Basic and diluted earnings (loss) per share $ 0.31 $ 0.56 $ 0.36 $ 0.04 $ 1.29 Basic and diluted weighted average shares outstanding 14,177,317 14,341,538 13,453,285 13,443,524 13,891,301 Tax-adjusted pro forma information Net income (loss) available to shareholders $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Pro forma provision for income taxes 1,130 2,104 1,254 175 4,663 Pro forma net income (loss) $ 3,300 $ 5,987 $ 3,570 $ 415 $ 13,272 Pro forma basic and diluted earnings (loss) per share $ 0.23 $ 0.42 $ 0.27 $ 0.03 $ 0.96 Basic and diluted weighted average shares outstanding 14,177,317 14,341,538 13,453,285 13,443,524 13,891,301 DMP acquisition occurred in Q4 of 2018.

Nature of business and summar_2

Nature of business and summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of presentation and consolidation	Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). They include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of estimates	Use of estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts and disclosures. Accordingly, actual results could differ from those estimates.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly-liquid investments purchased with original maturities of 90 days or less to be cash and cash equivalents.
Concentration of credit risk	Concentration of credit risk Financial instruments that potentially subject the Company to credit risk consist principally of bank balances above the Federal Deposit Insurance Corporation (FDIC) insurability limits of $250 per official custodian. The Company has not experienced any losses on these accounts and management believes the Company is not exposed to any significant credit risk on cash.
Accounts receivable	Accounts receivable Accounts receivable are generally uncollateralized customer obligations due under normal trade terms requiring payment within 30 to 60 days from the invoice date. Management periodically reviews past due balances and established an allowance for doubtful accounts of approximately $526 and $801 as of December 31, 2019 and 2018, respectively, for probable uncollectible amounts based on its assessment of the current status of individual accounts. The estimated valuation allowance results in a charge to earnings and the accounts are written-off through a charge to the valuation allowance and a credit to accounts receivable after the Company has used all reasonable collection efforts.
Inventories	Inventories Inventories are stated at the lower of cost, determined on the first-in, first-out method (FIFO), and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. Work-in-process and finished goods are valued at production cost consisting of material, labor and overhead. The Company maintains a reserve for obsolete and slow-moving inventory which is based upon the aging of current inventory as well as assumptions on future demand and market conditions.
Tooling in progress	Tooling in progress The Company has agreements with its customers to provide production tooling which will be used to produce specific parts for its customers. The costs to design, engineer, and manufacture the tooling are charged to tooling in progress as incurred and upon completion are sold to customers. The Company may also provide production tooling that is not sold to customers but is capitalized in property, plant and equipment. To the extent that estimated costs exceed expected reimbursement from the customer, the Company recognizes a loss. Tooling in progress was $1,589 and $2,318 as of December 31, 2019 and 2018, respectively.
Property, plant and equipment	Property, plant and equipment
Business combinations	Business combinations The Company accounts for all business combinations in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 805, Business Combinations. In connection with a business combination, the acquiring company must allocate the cost of the acquisition to assets acquired and liabilities assumed based on fair values as of the acquisition date. Any excess or shortage of amounts assigned to assets and liabilities over or under the purchase price is recorded as a gain on bargain purchase or goodwill. Transaction costs associated with acquisitions are expensed as incurred within selling, general and administrative expenses.
Goodwill	Goodwill We test goodwill for impairment annually, or more frequently if triggering events occur indicating that there may be an impairment. We have recorded goodwill and perform testing for potential goodwill impairment at a reporting unit level. A reporting unit is an operating segment, or a business unit one level below an operating segment for which discrete financial information is available, and for which management regularly reviews the operating results. Additionally, components within an operating segment can be aggregated as a single reporting unit if they have similar economic characteristics. We have performed testing on each of our reporting units which contain goodwill. We determine the fair value of our reporting units using multiple valuation methodologies, relying largely on an income approach but also incorporating value indicators from a market approach. Under the income approach, we calculate the fair value of a reporting unit based on the present value of estimated future cash flows. The income approach is dependent on several key management assumptions, including estimates of future sales, gross margins, operating costs, interest expense, income tax rates, capital expenditures, changes in working capital requirements and the weighted average cost of capital or the discount rate. Discount rate assumptions include an assessment of the risk inherent in the future cash flows of the reporting unit. Expected cash flows used under the income approach are developed in conjunction with our budgeting and forecasting process. Under the market approach, we estimate fair value of the reporting units using EBITDA multiples. The multiples are derived from comparable publicly traded companies with similar operating and investment characteristics as the respective reporting units. During the fourth fiscal quarters of 2019 and 2018, we performed our annual impairment assessments of goodwill, which did not indicate an impairment existed. For the twelve months ended December 31, 2018 we had two reporting units, DMP and MEC. The DMP reporting unit was acquired on December 14, 2018 and had preliminarily estimated goodwill of $29.2 million as of December 31, 2018. For the 18-day period from December 14 through December 31, 2018, DMP’s actual results of operations were above estimates utilized to determine the preliminary purchase price allocation. As a result, the fair value of the DMP reporting unit at December 31, 2018 is nominally above its carrying value. At December 31, 2018, the MEC reporting unit had goodwill with a carrying amount of approximately $40.2 million. The fair value of the MEC reporting unit substantially exceeded carrying value for 2018. For the twelve months ended December 31, 2019, we concluded that the DMP and MEC reporting units were integrated into one reporting unit. At December 31, 2019, the reporting unit had goodwill with a carrying amount of approximately $71.5 million. The fair value of this reporting unit substantially exceeded the carrying value for 2019. Changes to management assumptions and estimates utilized in the income and market approaches could negatively impact the fair value conclusions for our reporting units resulting in goodwill impairment. All key assumptions and valuations are determined by and are the responsibility of management. The factors used in the impairment analysis are inherently subject to uncertainty. We believe that the estimates and assumptions are reasonable to determine the fair value of our reporting units, however, if actual results are not consistent with these estimates and assumptions, goodwill and other intangible assets may be overstated which could trigger an impairment charge.
Fair value of financial instruments	Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable and long-term debt. The carrying amount of all significant financial instruments approximates fair value due to either the short maturity or the existence of variable interest rates that approximate prevailing market rates. Cash and cash equivalents, accounts receivable and accounts payable are classified as Level 1 fair value inputs as further described in Note 17. Long-term debt is classified as a Level 1 and Level 2 fair value input.
Impairment of long-lived assets	Impairment of long-lived assets When events or conditions warrant, the Company evaluates the recoverability of long-lived assets and considers whether these assets are impaired. The Company assesses the recoverability of these assets based on several factors, including management’s intention with respect to these assets and their projected undiscounted cash flows. If projected undiscounted cash flows are less than the carrying amount of the respective assets, the Company adjusts the carrying amounts of such assets to their estimated fair value. To the extent that the carrying value of the net assets of a reportable unit is greater than the estimated fair value, the Company may be required to record impairment charges.
Deferred financing costs	Deferred financing costs Loan issuance costs and discounts are capitalized upon the issuance of long-term debt and amortized over the life of the related debt and are presented as a reduction of the associated long-term debt on the consolidated balance sheets. Loan issuance costs associated with revolving debt arrangements are presented as a component of other assets. Loan issuance costs incurred in connection with revolving debt arrangements are amortized using the straight-line method over the life of the credit agreement. Loan issuance costs and discounts incurred in connection with term debt are amortized using the effective interest method. Amortization of deferred loan issuance costs and discounts are included in interest expense. During 2019, 2018 and 2017 the Company recorded $142, $2,173 and $412, respectively of deferred financing costs associated with its long-term debt and line of credit arrangements. Amortization expense associated with the deferred debt issuance costs and discounts in 2019, 2018 and 2017 was approximately $381, $198 and $249. Accumulated amortization was approximately $474, $114 and $619 as of December 31, 2019, 2018 and 2017, respectively. Amendments made to existing debt in 2019, 2018 and 2017 resulted in the write-offs of $154, $814 and zero, respectively of unamortized costs associated with the debt that was replaced.
Revenue recognition	Revenue recognition The Company adopted ASC 606 January 1, 2019, where the Company recognizes revenue for the transfer of goods or services to a customer in an amount that reflects the consideration it expects to receive in exchange for those goods or services. When goods are shipped, the customer takes ownership at shipment, and this is when control transfers. Sales are supported by documentation such as supply agreements and purchase order, which specify certain terms and conditions including product specifications, quantities, fixed prices, delivery dates and payments terms. Revenue related to services is recognized in the period services are performed, thus the Company recognizes revenue at a point in time. There are many customers where the Company designs, engineers and builds production tooling, which is purchased by the customer. Revenue is recognized when the tooling is completed, the customer signs off the product through the Product Part Approval Process (PPAP) and the tool is placed into service. Revenue related to production tooling is recognized as a point in time when it meets the PPAP criteria. The Company offers certain customers discounts for early payments. These discounts are recorded against net sales in the consolidated statement of comprehensive income and accounts receivable in the consolidated balance sheet. The Company does not offer any other customer incentives, rebates or allowances.
Shipping and handling	Shipping and handling The Company expenses shipping and handling costs as incurred. These costs are generally comprised of salaries and wages, shipping supplies and warehouse costs. These costs are included in cost of sales on the consolidated statements of comprehensive income. The Company does not charge customers nor recognize revenue for shipping and handling. The Company’s OEM customers arrange and pay the freight for delivery.
Advertising	Advertising The Company expenses the costs of advertising when incurred. Advertising expense was approximately $110, $116 and $157 for the twelve months ended December 31, 2019, 2018 and 2017, respectively. Advertising costs are charged to selling, general and administrative expenses.
Income Taxes	Income Taxes Income taxes and uncertain tax positions are accounted for in accordance with ASC 740, “Accounting for Income Taxes”. Deferred income taxes are provided for the differences between the bases of assets and liabilities for financial reporting and income tax purposes. The Company measures deferred tax assets and liabilities using enacted tax rates in effect for the years in which the differences are expected to reverse and recognizes the effect of a change in enacted rates in the period of enactment. Tax positions meeting the more-likely-than-not recognition threshold are measured pursuant to the guidance set forth in ASC 740. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. See Note 11 “Income Taxes” of these Notes to Consolidated Financial Statements for further discussion.
Earnings per share	Earnings per share The Company computes basic earnings (loss) per share by dividing net income (loss) available to shareholders by the actual weighted average number of common shares outstanding for the reporting period. The Company does not have any potentially dilutive convertible securities. As a result, basic and diluted earnings per share for the Company are the same.
Treasury Stock	Treasury Stock Treasury stock purchases are accounted for under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock. Subsequent reissuance of shares to the ESOP are recorded as a reduction to treasury stock and as ESOP expense in the consolidated statement of comprehensive income.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, FASB issued Accounting Standard Update (ASU) 2014-09, Revenue from Contracts with Customers (ASU 2014-09), and issued subsequent amendments to the initial guidance within ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations (ASU 2016-08) issued in March 2016, ASU 2016-10, Revenue from Contracts with Customers, Identifying Performance Obligations and Licensing (ASU 2016-10) issued in April 2016, ASU 2016-12, Revenue from Contracts with Customers, Narrow-Scope Improvements and Practical Expedients (ASU 2016-12) issued in May 2016 and ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers (ASU 2016-20) issued in December 2016 (ASU 2014-09, ASU 2016-08, ASU 2016-10, ASU 2016-12 and ASU 2016-20 collectively “Topic 606”). Topic 606 provides a comprehensive revenue recognition model requiring companies to recognize revenue for the transfer of goods or services to a customer in an amount that reflects the consideration it expects to receive in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In July 2015, the FASB voted to defer the effective date of ASU 2014-09 by one year, and therefore the standard is effective for the Company's annual and interim periods beginning after December 15, 2019. Effective January 1, 2019, the Company implemented the new standard using a five-step model specified in the guidance using the modified retrospective method. The implementation did not have a material impact on the consolidated financial statements and there was no adjustment to retained earnings from implementation. In February 2016, the FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments, which establishes ASC 326, Financial Instruments – Credit Losses. The ASU revises the measurement of credit losses for financial assets measured at amortized cost from an incurred loss methodology to an expected loss methodology. The ASU affects trade receivables, debt securities, net investment in leases, and most other financial assets that represent a right to receive cash. Additional disclosures about significant estimates and credit quality are also required. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses. This ASU clarifies that receivables from operating leases are accounted for using the lease guidance and not as financial instruments. In January 2017, the FASB issued ASU 2017-01, Clarifying the Definition of a Business, which narrows the application of when an integrated set of assets and activities is considered a business and provides a framework to assist entities in evaluating whether both an input and a substantive process are present to be considered a business. It is expected that the new guidance will reduce the number of transactions that would need to be further evaluated and accounted for as a business. For public companies, this guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years. For as long as the Company remains an EGC, the new guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within annual periods beginning after December 15, 2019. Early adoption is permitted. The Company is evaluating the potential impact of adopting this guidance on the consolidated financial statements. In January 2017, the FASB issued ASU, 2017-04, Simplifying the Test for Goodwill Impairment, which simplifies the subsequent measurement of goodwill by removing the requirement to perform a hypothetical purchase price allocation to compute the implied fair value of goodwill to measure impairment. Instead, any goodwill impairment will equal the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Further, the guidance eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. For public companies, this guidance is effective for annual or any interim goodwill impairment test in annual reporting periods beginning after December 15, 2020. For as long as the Company remains an EGC, the new guidance is effective for any annual or interim goodwill impairment test in annual reporting periods beginning after December 15, 2021. The adoption of this guidance is not expected to have a material impact on the consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement (ASU 2018-13) to improve the effectiveness of fair value measurement disclosures. The amendments in this Update modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement based on the concepts in FASB Concept Statement, including the consideration of costs and benefits. The amendments in this Update are effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption of this guidance is permitted for removed or modified disclosures upon issuance of this Update while a delayed adoption of the additional disclosures is allowed until the effective date. The Company is evaluating the impact of this standard on its financial statements.

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed	The estimated fair values of assets acquired, and liabilities assumed are as follows: Opening Balance Sheet Allocation Cash consideration at acquisition date, net of cash received $ 114,700 Cash consideration for net working capital adjustment 2,368 Contingent consideration fair value as of acquisition date 6,076 Total purchase price $ 123,144 Accounts receivable, net $ 26,927 Tooling in progress 1,318 Inventory, net 13,237 Property, plant and equipment, net 30,017 Other assets, net of cash 416 Intangible assets Trade name 14,780 Customer relationships 44,550 Non-compete 8,800 Goodwill 31,333 Total assets acquired 171,378 Deferred income taxes 20,221 Other liabilities 28,014 Net assets acquired $ 123,144
Summary of Pro Forma Results of Operations	The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the acquisition. Twelve Months Ended December 31, 2018 Net sales $ 523,721 Net income 17,151

Select balance sheet data (Tabl

Select balance sheet data (Tables)	12 Months Ended
	Dec. 31, 2019
Select Balance Sheet Data [Abstract]
Schedule of Inventories	Inventories as of December 31, 2019 and December 31, 2018 consist of: December 31, 2019 December 31, 2018 Finished goods and purchased parts $ 28,664 $ 32,589 Raw materials 10,834 12,329 Work-in-process 6,194 8,487 Total $ 45,692 $ 53,405
Schedule of Property, Plant and Equipment	Property, plant and equipment as of December 31, 2019 and December 31, 2018 consist of: Useful Lives Years* December 31, 2019 December 31, 2018 Land Indefinite $ 1,264 $ 1,264 Land improvements 15-39 3,169 3,169 Building and building improvements 15-39 58,021 55,269 Machinery, equipment and tooling 3-10 204,248 182,045 Vehicles 5 3,738 3,613 Office furniture and fixtures 3-7 15,469 14,253 Construction in progress N/A 3,154 6,786 Total property, plant and equipment, gross 289,063 266,399 Less accumulated depreciation 164,000 142,516 Total property, plant and equipment, net $ 125,063 $ 123,883
Schedule of Changes In Goodwill	Changes in goodwill between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 69,437 DMP purchase accounting adjustments, net (270 ) DMP net working capital true-up 2,368 Balance as of December 31, 2019 $ 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 December 31, 2019 and December 31, 2018: Useful Lives Years December 31, 2019 December 31, 2018 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 (33,582 ) (22,876 ) Total amortizable intangible assets, net 68,362 79,068 Non-amortizable brand name 3,811 3,811 Total intangible assets, net $ 72,173 $ 82,879
Schedule of Changes In Intangible Assets	Changes in intangible assets between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 82,879 Amortization expense (10,706 ) Balance as of December 31, 2019 $ 72,173

Other long-term debt (Tables)

Other long-term debt (Tables)	12 Months Ended
	Dec. 31, 2019
Other Longterm Debt [Abstract]
Summary of Other Long-Term Debt	Other long-term debt as of December 31, 2019 and December 31, 2018 consisted of the following: December 31, 2019 December 31, 2018 Interest Rate Balance Interest Rate Balance Term A loans – 2018 financing package N/A $ — 4.69 % $ 69,000 Real estate term loan – 2018 financing package N/A — 4.69 % 26,000 Strategic capital loan N/A — 11.78 % 25,000 Wisconsin Economic Development Corporate (Neillsville) N/A — 2.00 % 406 Smyth County, Virginia N/A — 0.00 % 700 Total principal outstanding — 121,106 Less: Unamortized debt issuance costs — (825 ) Less: Current maturities — (8,606 ) Long-term debt, less current maturities, net $ — $ 111,675

Capital lease obligation (Table

Capital lease obligation (Tables)	12 Months Ended
	Dec. 31, 2019
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 $ 734 2021 734 2022 734 2023 734 2024 514 Thereafter 226 Total 3,676 Less payment amount allocated to interest 392 Present value of capital lease obligation $ 3,285 Current portion of capital lease obligation 598 Long-term portion of capital lease obligation 2,687 Total capital lease obligation $ 3,285

Operating lease obligation (Tab

Operating lease obligation (Tables)	12 Months Ended
	Dec. 31, 2019
Lessee Disclosure [Abstract]
Future Minimum Lease Payments Under Lease	Operating leases relate to property, plant and equipment. Future minimum lease payments required under the lease are as follows: Year ending December 31, 2020 $ 3,402 2021 2,725 2022 1,923 2023 1,792 2024 830 Thereafter 2,094 Total $ 12,766

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income Taxes	Income taxes are included in the consolidated statements of income at December 31, 2019 and 2018 as below: (in thousands) December 31, 2019 December 31, 2018 Current income tax expense (benefit) U.S Federal $ 401 $ (126 ) State 1,544 614 Total 1,945 488 Deferred income tax benefit U.S Federal (4,197 ) (793 ) State (1,836 ) (154 ) Total (6,033 ) (947 ) Total income tax benefit $ (4,088 ) $ (459 )
Schedule of Reconciliation of Statutory Federal Income Tax Expense to Income Tax Expense	A reconciliation of the statutory federal income tax expense to the income tax expense from continuing operations provided at December 31, 2019 and 2018, is as follows: (in thousands) December 31, 2019 December 31, 2018 Income tax expense at the federal statutory rate - 21% $ (1,854 ) $ (388 ) State and local income taxes - net of federal income tax benefits (58 ) (61 ) Compensation deduction limitation - section 162(m) adjustment 357 — Income taxed by shareholder before IPO (867 ) — Other - perms 77 171 Transaction Costs 607 — Change in tax status (2,355 ) — Tax credits generated (254 ) — Other misc. tax 259 (181 ) Total income tax benefit $ (4,088 ) $ (459 ) Effective tax rate 47.5 % -2.5 %
Components of Deferred Income Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities are presented below: (in thousands) December 31, 2019 December 31, 2018 Deferred tax assets: Deferred compensation $ 8,645 $ 226 Inventory adjustments 1,837 — Accrued expenses 211 — Credits 279 — Net operating loss 3,120 949 Other — 288 Total deferred tax assets 14,092 1,464 Deferred tax liabilities: Property, plant and equipment 8,354 4,379 Intangibles 19,305 16,034 Inventory adjustment — 175 Other 622 — Total deferred tax liabilities 28,281 20,587 Valuation allowance — — Net deferred tax liability $ (14,188 ) $ (19,123 )
Consolidated State NOL's Commence Expiry	Consolidated federal NOL’s are $13,827 and do not expire. In addition, consolidated state NOL’s commence expire as follows: (in thousands) Amount Expire Commencing Illinois $ 2,141 2039

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule of Company's Net Sales From External Customers	The Company does not earn revenues or have long-lived asset located in foreign countries. In accordance with the enterprise-wide disclosure requirements of ASC 280, the Company’s net sales from external customers by main product lines are as follows: Twelve Months Ended December 31, 2019 2018 2017 Outdoor sports $ 7,181 $ 6,862 $ 7,896 Fabrication 334,340 147,099 129,387 Performance structures 71,881 84,231 87,742 Tube 71,108 80,715 65,440 Tank 40,033 39,641 27,359 Total 524,544 358,550 317,824 Intercompany sales elimination (4,839 ) (4,024 ) (4,493 ) Total, net sales $ 519,704 $ 354,526 $ 313,331

Fair value of financial instr_2

Fair value of financial instruments (Tables)	12 Months Ended
	Dec. 31, 2019
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 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 at Report Date Using Balance at December 31, 2018 (Level 1) (Level 2) (Level 3) Deferred compensation $ 13,351 $ — $ — $ 13,351 Contingent consideration payable 6,054 — — 6,054 Total $ 19,405 $ — $ — $ 19,405
Summary of Changes in Liabilities at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)	Changes in liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) between December 31, 2018 and December 31, 2019 consist of: Balance as of December 31, 2018 $ 19,405 Contingent consideration revaluation (6,054 ) Deferred compensation adjustments 11,673 Payments (75 ) Transfer to level 1 and level 2 investments (24,949 ) Balance as of December 31, 2019 $ —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
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 twelve months ended December 31, 2019. (in thousands) Contract Assets Contract Liabilities As of January 1, 2019 $ 2,318 $ 977 Net Activity (729 ) (63 ) As of December 31, 2019 $ 1,589 $ 914
Schedule of Disaggregation of Revenue by Product Category	The following table represents a disaggregation of revenue by product category: Twelve Months Ended December 31, 2019 2018 2017 Outdoor sports $ 7,181 $ 6,862 $ 7,896 Fabrication 334,340 147,099 129,387 Performance structures 71,881 84,231 87,742 Tube 71,108 80,715 65,440 Tank 40,033 39,641 27,359 Total 524,544 358,550 317,824 Intercompany sales elimination (4,839 ) (4,024 ) (4,493 ) Total, net sales $ 519,704 $ 354,526 $ 313,331

Temporary Equity (Tables)

Temporary Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Temporary Equity [Abstract]
Schedule of Changes to Temporary Equity	The following table shows all changes to temporary equity during the twelve months ended December 31, 2019, excluding net income for the period of April 1, 2019 through the date of the IPO. Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings Balance as of January 1, 2018 $ 125,042 $ (49,826 ) $ 17,671 Net Income 17,936 Purchase of treasury shares (11,833 ) Redistribution of Stockholders Share 4,000 Change in redemption value of outstanding redeemable common shares, net 8,764 (8,764 ) Balance as of December 31, 2018 $ 133,806 $ (57,659 ) $ 26,842 Temporary Equity Redeemable Common Shares Treasury Shares Retained Earnings Balance as of January 1, 2019 $ 133,806 $ (57,659 ) $ 26,842 Net income pre IPO — — 2,856 Transfer from temporary equity to common equity (133,806 ) 57,659 (29,698 ) Balance as of December 31, 2019 $ — $ — $ —

Concentration of major custom_2

Concentration of major customers (Tables)	12 Months Ended
	Dec. 31, 2019
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 Twelve Months Ended December 31, As of As of 2019 2018 2017 December 31, 2019 December 31, 2018 Customer A 15.1 % 22.6 % 20.2 % <10 % <10 % B 13.5 % 19.3 % 19.8 % <10 % <10 % C <10 % 17.4 % 14.7 % <10 % <10 % D 13.1 % <10 % <10 % <10 % 12.6 % E <10 % <10 % <10 % 13.5 % 10.2 % F <10 % <10 % <10 % 10.4 % <10 %

Valuation and qualifying acco_2

Valuation and qualifying accounts (Tables)	12 Months Ended
	Dec. 31, 2019
Valuation And Qualifying Accounts [Abstract]
Schedule Of Valuation And Qualifying Accounts	Description Balance at beginning of period Additions Deductions Balance at end of period Year ended December 31, 2019 Allowance for doubtful accounts $ 801 $ 308 $ 583 $ 526 Year ended December 31, 2018 Allowance for doubtful accounts $ 308 $ 541 $ 48 $ 801

Quarterly Results of Operatio_2

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Unaudited Quarterly Results of Operations	The following tables present our unaudited quarterly results of operations for the eight quarters in 2019 and 2018. This unaudited information has been prepared on the same basis as our audited consolidated financial statements and includes all adjustments, consisting only of normal recurring adjustments, that we consider necessary for fair statement of our consolidated financial position and operating results for the quarters presented. This unaudited information should be read in conjunction with the consolidated financial statements and related notes included in Part II, Item 8 of this Annual Report on Form 10-K. Our operating results for any quarter are not necessarily indicative of results for any future quarters or for a full year. Q1 Q2 Q3 Q4 Full Year (in thousands, except share amounts and per share data) 2019 2019 2019 2019 2019 Net sales $ 143,732 $ 145,130 $ 128,511 $ 102,331 $ 519,704 Cost of sales 124,153 124,595 113,941 98,297 460,986 Amortization of intangibles 2,677 2,677 2,677 2,677 10,706 Profit sharing, bonuses, and deferred compensation 1,750 22,830 678 (153 ) 25,105 Employee Stock Ownership Plan expense 1,500 1,500 1,500 953 5,453 Other selling, general and administrative expenses 6,723 7,506 6,068 5,170 25,466 Contingent consideration revaluation 869 2,674 (9,598 ) — (6,054 ) Income (loss) from operations 6,060 (16,652 ) 13,245 (4,612 ) (1,958 ) Interest expense (2,832 ) (1,991 ) (987 ) (918 ) (6,728 ) Loss on extinguishment of debt — (154 ) — — (154 ) Income (loss) before taxes 3,228 (18,797 ) 12,258 (5,530 ) (8,840 ) Income tax benefit 769 (3,513 ) 2,512 (3,857 ) (4,088 ) Net income (loss) and comprehensive income (loss) $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Earnings (loss) per share Net income (loss) available to shareholders $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Basic and diluted earnings (loss) per share $ 0.18 $ (0.91 ) $ 0.49 $ (0.08 ) $ (0.27 ) Basic and diluted weighted average shares outstanding 13,443,484 16,799,915 19,740,296 19,711,921 17,447,464 Tax-adjusted pro forma information Net income (loss) available to shareholders $ 2,459 $ (15,284 ) $ 9,746 $ (1,673 ) $ (4,753 ) Pro forma provision for income taxes 70 103 — — 173 Pro forma net income (loss) $ 2,389 $ (15,387 ) $ 9,746 $ (1,673 ) $ (4,926 ) Pro forma basic and diluted earnings (loss) per share $ 0.18 $ (0.92 ) $ 0.49 $ (0.08 ) $ (0.28 ) Basic and diluted weighted average shares outstanding 13,443,484 16,799,915 19,740,296 19,711,921 17,447,464 IPO occurred in Q2 of 2019. Q1 Q2 Q3 Q4 Full Year (in thousands, except share amounts and per share data) 2018 2018 2018 2018 2018 Net sales $ 87,221 $ 91,535 $ 84,338 $ 91,431 $ 354,526 Cost of sales 75,411 75,986 71,517 81,035 303,948 Amortization of intangibles 939 939 939 1,279 4,096 Profit sharing, bonuses, and deferred compensation 1,640 1,365 2,340 2,713 8,058 Employee Stock Ownership Plan expense 1,000 1,000 1,000 1,000 4,000 Other selling, general and administrative expenses 2,867 2,713 2,855 3,841 12,276 Contingent consideration revaluation — — — (21 ) (21 ) Income (loss) from operations 5,364 9,532 5,687 1,585 22,169 Interest expense (906 ) (853 ) (846 ) (1,274 ) (3,879 ) Loss on extinguishment of debt — (588 ) — (226 ) (814 ) Income (loss) before taxes 4,458 8,091 4,841 85 17,476 Income tax benefit 29 — 17 (505 ) (459 ) Net income (loss) and comprehensive income (loss) $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Earnings (loss) per share Net income (loss) available to shareholders $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Basic and diluted earnings (loss) per share $ 0.31 $ 0.56 $ 0.36 $ 0.04 $ 1.29 Basic and diluted weighted average shares outstanding 14,177,317 14,341,538 13,453,285 13,443,524 13,891,301 Tax-adjusted pro forma information Net income (loss) available to shareholders $ 4,430 $ 8,091 $ 4,824 $ 590 $ 17,935 Pro forma provision for income taxes 1,130 2,104 1,254 175 4,663 Pro forma net income (loss) $ 3,300 $ 5,987 $ 3,570 $ 415 $ 13,272 Pro forma basic and diluted earnings (loss) per share $ 0.23 $ 0.42 $ 0.27 $ 0.03 $ 0.96 Basic and diluted weighted average shares outstanding 14,177,317 14,341,538 13,453,285 13,443,524 13,891,301 DMP acquisition occurred in Q4 of 2018.

Nature of business and summar_3

Nature of business and summary of significant accounting policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)FacilityReportingUnit	Dec. 31, 2018USD ($)ReportingUnit	Dec. 31, 2017USD ($)
Accounting Policies [Line Items]
Number of facilities operated | Facility	20
ESOP, plan description	From January 2003 until the Company’s initial public offering of its common stock (IPO) in May 2019, the ESOP owned 100% of the Company’s outstanding shares of common stock which have been fully allocated to active or retired eligible employees.
Percentage of outstanding shares of common stock owned by ESOP	100.00%
Allowance for doubtful accounts receivable	$ 526,000	$ 801,000
Tooling in progress	1,589,000	2,318,000
Depreciation expense	$ 22,296,000	$ 16,372,000	$ 16,975,000
Number of reporting units | ReportingUnit	1	2
Goodwill	$ 71,535,000	$ 69,437,000
Deferred financing costs	142	2,173,000	412,000
Amortization of debt issuance costs and discounts	381,000	198,000	249,000
Accumulated amortization	474	114,000	619,000
Write-offs of debt unamortized costs	154,000	814,000	0
Advertising expense	110,000	116,000	157,000
Topic 606 [Member]
Accounting Policies [Line Items]
Adjustment to retained earnings	0
Mayville Engineering Company, Inc [Member]
Accounting Policies [Line Items]
Goodwill		40,200,000
Defiance Metal Products Co. [Member]
Accounting Policies [Line Items]
Goodwill		29,200,000
Cost of Sales [Member]
Accounting Policies [Line Items]
Depreciation expense	$ 22,296,000	$ 16,372,000	$ 16,975,000

IPO - Additional Information (D

IPO - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	May 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Initial Public Offering [Line Items]
Conversion of stock Employee Stock Ownership Plan	10,075
Shares in Employee Stock Ownership Plan	13,443,484	11,790,113	13,443,484
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%

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - USD ($) $ in Thousands	Dec. 14, 2018	Jan. 01, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Contingent consideration payable	$ 6,076
Business combination inventory fair value step-up											$ 395	$ 583
Business combination, gain (loss) on contingent consideration liability											6,054
Increase (decrease) in account receivable			$ 27								27
Increase (decrease) in inventory			1,508								1,508
Increase (decrease) in property plant and equipment			(36)								(36)
Increase (decrease) in deferred income taxes											1,097
Increase (decrease) in other liabilities			31								31
Working capital					$ 2,368
Net sales												523,721
Net income												17,151
Loss on extinguishment of debt					(154)		$ (226)		$ (588)		(154)	(814)
Income tax benefit			(3,857)	$ 2,512	(3,513)	$ 769	(505)	$ 17		$ 29	$ (4,088)	(459)	$ 0
Assumed income tax rate											26.00%
Restatement Adjustment [Member]
Business Acquisition [Line Items]
Contingent consideration payable			0	9,598							$ 0
Restatement Adjustment [Member] | ASC 805 [Member]
Business Acquisition [Line Items]
Business combination inventory fair value step-up		$ 978
Net income												$ 17,151
Net expense		914
Loss on extinguishment of debt		(257)
Income tax benefit		$ 260
Assumed income tax rate		26.00%
Trade Names [Member]
Business Acquisition [Line Items]
Estimated useful life											10 years	10 years
Noncompete Agreements [Member]
Business Acquisition [Line Items]
Estimated useful life											5 years	5 years
Defiance Metal Products Co. [Member]
Business Acquisition [Line Items]
Cash consideration including working capital adjustment, net of cash received	117,068				117,068						$ 117,068
Contingent consideration payable	6,076			0	9,598	6,924	$ 6,054					$ 6,054
Business combination, contingent consideration arrangements, description											The Company acquired DMP for $117,068, net of cash received, plus potential contingent consideration of up to $10,000. The Company would have paid DMP’s previous shareholders $7,500 if DMP generated $19,748 of EBITDA, as defined by the stock purchase agreement, over the twelve-month period ended September 30, 2019. In addition, the Company would have paid one dollar for each additional dollar of EBITDA in excess of $19,748 generated over this period; however, in no event would the total have payment exceeded $10,000.
Business combination inventory fair value step-up												978
Business combination, gain (loss) on contingent consideration liability				(9,598)	2,674	$ 869						$ (21)
Contingent consideration threshold				19,748
Working capital	2,368
Net sales											$ 193,420
Net income											10,903
Defiance Metal Products Co. [Member] | Restatement Adjustment [Member]
Business Acquisition [Line Items]
Contingent consideration payable			$ 0	$ 0	$ 9,598						$ 0
Defiance Metal Products Co. [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Business combination, Recognized identifiable assets acquired and liabilities assumed, intangible assets, other than goodwill	$ 14,780
Estimated useful life	10 years
Defiance Metal Products Co. [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Business combination, Recognized identifiable assets acquired and liabilities assumed, intangible assets, other than goodwill	$ 44,550
Estimated useful life	12 years
Defiance Metal Products Co. [Member] | Noncompete Agreements [Member]
Business Acquisition [Line Items]
Business combination, Recognized identifiable assets acquired and liabilities assumed, intangible assets, other than goodwill	$ 8,800
Estimated useful life	5 years
Defiance Metal Products Co. [Member] | Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration payable	$ 10,000

Acquisition - Schedule of Estim

Acquisition - Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 14, 2018	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Mar. 31, 2019
Business Acquisition [Line Items]
Cash consideration at acquisition date, net of cash received			$ 2,369	$ 114,700
Cash consideration for net working capital adjustment		$ 2,368
Contingent consideration fair value as of acquisition date	$ 6,076
Goodwill			$ 71,535	69,437
Defiance Metal Products Co. [Member]
Business Acquisition [Line Items]
Cash consideration at acquisition date, net of cash received	114,700
Cash consideration for net working capital adjustment	2,368
Contingent consideration fair value as of acquisition date	6,076	$ 9,598		$ 6,054	$ 0	$ 6,924
Total purchase price	123,144
Accounts receivable, net	26,927
Tooling in progress	1,318
Inventory, net	13,237
Property, plant and equipment, net	30,017
Other assets, net of cash	416
Goodwill	31,333
Total assets acquired	171,378
Deferred income taxes	20,221
Other liabilities	28,014
Net assets acquired	123,144
Trade Names [Member] | Defiance Metal Products Co. [Member]
Business Acquisition [Line Items]
Intangible assets	14,780
Customer Relationships [Member] | Defiance Metal Products Co. [Member]
Business Acquisition [Line Items]
Intangible assets	44,550
Noncompete Agreements [Member] | Defiance Metal Products Co. [Member]
Business Acquisition [Line Items]
Intangible assets	$ 8,800

Acquisition - Summary of Pro Fo

Acquisition - Summary of Pro Forma Results of Operations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Business Combinations [Abstract]
Net sales	$ 523,721
Net income	$ 17,151

Select balance sheet data - Sch

Select balance sheet data - Schedule of Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Select Balance Sheet Data [Abstract]
Finished goods and purchased parts	$ 28,664	$ 32,589
Raw materials	10,834	12,329
Work-in-process	6,194	8,487
Total	$ 45,692	$ 53,405

Select balance sheet data - Add

Select balance sheet data - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Select Balance Sheet Data [Abstract]
Inventory	$ 45,692				$ 53,405				$ 45,692	$ 53,405
Amortization of the DMP inventory fair value									395	583
Amortization expense	2,677	$ 2,677	$ 2,677	$ 2,677	$ 1,279	$ 939	$ 939	$ 939	10,706	$ 4,096	$ 3,756
Future amortization expense, 2020	10,706								10,706
Future amortization expense, 2021	10,706								10,706
Future amortization expense, 2022	6,952								6,952
Future amortization expense, 2023	6,865								6,865
Future amortization expense, 2024	$ 5,192								$ 5,192

Select balance sheet data - S_2

Select balance sheet data - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 289,063	$ 266,399
Less accumulated depreciation	164,000	142,516
Total property, plant and equipment, net	125,063	123,883
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	$ 58,021	55,269
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	$ 204,248	182,045
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	$ 3,738	3,613
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	$ 15,469	14,253
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	$ 3,154	$ 6,786

Select balance sheet data - S_3

Select balance sheet data - Schedule of Changes In Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Select Balance Sheet Data [Abstract]
Balance	$ 69,437
DMP purchase accounting adjustments, net	(270)
DMP net working capital true-up	2,368
Balance	$ 71,535

Select balance sheet data - S_4

Select balance sheet data - Schedule of Listing of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Amortizable intangible assets [Abstract]
Accumulated amortization	$ (33,582)	$ (22,876)
Total amortizable intangible assets, net	68,362	79,068
Total intangible assets, net	72,173	82,879
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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Select Balance Sheet Data [Abstract]
Balance				$ 82,879					$ 82,879
Amortization expense	$ (2,677)	$ (2,677)	$ (2,677)	$ (2,677)	$ (1,279)	$ (939)	$ (939)	$ (939)	(10,706)	$ (4,096)	$ (3,756)
Balance	$ 72,173				$ 82,879				$ 72,173	$ 82,879

Bank revolving credit notes - A

Bank revolving credit notes - Additional Information (Details) - USD ($)	Sep. 26, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 25, 2019
Line Of Credit Facility [Line Items]
Interest coverage ratio		7.42%
Consolidated leverage ratio		1.39%
Revolving credit notes		$ 72,572,000	$ 59,629,000
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]
Credit agreement borrowing capacity				$ 90,000,000
Interest rate		3.25%	4.69%
Revolving commitments fee percentage		0.20%	0.20%
Revolving credit notes		$ 72,572,000	$ 59,629,000
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

Other long-term debt - Addition

Other long-term debt - Additional Information (Details) - USD ($) $ in Thousands	Sep. 25, 2019	Jun. 30, 2019	May 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Long-term Debt [Line Items]
Borrowing financing package					$ 121,106
Repayments of other long-term debt				$ 120,046	87,389	$ 9,099
Smyth County, Virginia [Member]
Other Long-term Debt [Line Items]
Borrowing financing package					700
Loan forgiven		$ 521
Facility Financing Package [Member]
Other Long-term Debt [Line Items]
Borrowing financing package	$ 95,000
Maturity date	Dec. 14, 2023
Strategic Capital Loan [Member]
Other Long-term Debt [Line Items]
Borrowing financing package	$ 25,000				$ 25,000
Maturity date	Jun. 14, 2024
Repayments of other long-term debt			$ 25,000
Term A loan [Member]
Other Long-term Debt [Line Items]
Repayments of other long-term debt			$ 43,000

Other long-term debt - Summary

Other long-term debt - Summary of Other Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 25, 2019	Dec. 31, 2018
Other Long-term Debt [Line Items]
Total principal outstanding		$ 121,106
Less: Unamortized debt issuance costs		(825)
Less: Current maturities		(8,606)
Long-term debt, less current maturities, net		$ 111,675
Smyth County, Virginia [Member]
Other Long-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		0.00%
Total principal outstanding		$ 700
Term A Financing Packaging [Member]
Other Long-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.69%
Total principal outstanding		$ 69,000
Real Estate Term Loan [Member]
Other Long-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.69%
Total principal outstanding		$ 26,000
Strategic Capital Loan [Member]
Other Long-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		11.78%
Total principal outstanding	$ 25,000	$ 25,000
Wisconsin Economic Development Corporate [Member]
Other Long-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.00%
Total principal outstanding		$ 406

Capital lease obligation - Addi

Capital lease obligation - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 3,285
Non-cash capital lease transactions	1,776	$ 2,051	$ 0
Equipment [Member]
Capital Leased Assets [Line Items]
Capitalized cost	3,825
Capital lease, accumulated depreciation	598
Capital lease, depreciation recognized	$ 503

Capital lease obligation - Sche

Capital lease obligation - Schedule of Future Minimum Lease Payments Required Under The Lease (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
2020	$ 734
2021	734
2022	734
2023	734
2024	514
Thereafter	226
Total	3,676
Less payment amount allocated to interest	392
Present value of capital lease obligation	3,285
Current portion of capital lease obligation	598	$ 281
Long-term portion of capital lease obligation	2,687	$ 1,697
Total capital lease obligation	$ 3,285

Operating lease obligation - Fu

Operating lease obligation - Future Minimum Lease Payments Under Lease (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2020	$ 3,402
2021	2,725
2022	1,923
2023	1,792
2024	830
Thereafter	2,094
Total	$ 12,766

Operating lease obligation - Ad

Operating lease obligation - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee Disclosure [Abstract]
Operating lease expiration period	2028-12
Rent expense	$ 4,801	$ 2,052	$ 1,856

Employee stock ownership plan -

Employee stock ownership plan - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	May 13, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 31, 2019
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Annual contribution vesting percentage										3.00%
Employee stock ownership plan (ESOP), compensation expense		$ 953	$ 1,500	$ 1,500	$ 1,500	$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 5,453	$ 4,000	$ 4,000
Shares in ESOP		11,790,113				13,443,484				11,790,113	13,443,484		13,443,484
Repurchase obligation estimated fair value on allocated shares						$ 133,806					$ 133,806
Estimated fair value of common stock on ESOP											$ 9.95
May 2019 IPO [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Dividend stock split conversion ratio	133434.00%
Employee Stock Option [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee stock ownership plan (ESOP), compensation expense										$ 5,453	$ 4,000	$ 4,000

Retirement plans - Additional I

Retirement plans - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Percentage of employee contribution of eligible compensation plan	50.00%
Defined contribution plan, employer discretionary contribution amount	$ 0	$ 696	$ 671

Income taxes - Schedule of Inco

Income taxes - Schedule of Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current income tax expense (benefit)
U.S Federal								$ 401	$ (126)
State								1,544	614
Total								1,945	488
Deferred income tax benefit
U.S Federal								(4,197)	(793)
State								(1,836)	(154)
Total								(6,033)	(947)
Total income tax benefit	$ (3,857)	$ 2,512	$ (3,513)	$ 769	$ (505)	$ 17	$ 29	$ (4,088)	$ (459)	$ 0

Income taxes - Schedule of Reco

Income taxes - Schedule of Reconciliation of Statutory Federal Income Tax Expense to Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax expense at the federal statutory rate - 21%								$ (1,854)	$ (388)
State and local income taxes - net of federal income tax benefits								(58)	(61)
Compensation deduction limitation - section 162(m) adjustment								357
Income taxed by shareholder before IPO								(867)
Other - perms								77	171
Transaction Costs								607
Change in tax status								(2,355)
Tax credits generated								(254)
Other misc. tax								259	(181)
Total income tax benefit	$ (3,857)	$ 2,512	$ (3,513)	$ 769	$ (505)	$ 17	$ 29	$ (4,088)	$ (459)	$ 0
Effective tax rate								47.50%	(2.50%)

Income taxes - Schedule of Re_2

Income taxes - Schedule of Reconciliation of Statutory Federal Income Tax Expense to Income Tax Expense (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Percentage of federal statutory rate	21.00%	21.00%

Income taxes - Additional Infor

Income taxes - Additional Information (Details) - USD ($)	3 Months Ended							12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax [Line Items]
Income tax benefit	$ (3,857,000)	$ 2,512,000	$ (3,513,000)	$ 769,000	$ (505,000)	$ 17,000	$ 29,000	$ (4,088,000)	$ (459,000)	$ 0
Tax expense for interest and penalties								0
Federal [Member]
Income Tax [Line Items]
Net operating loss carryforwards	13,827,000							$ 13,827,000
Tax years open for examination								2016
State [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 2,141,000							$ 2,141,000
Tax years open for examination								2015

Income taxes - Components of De

Income taxes - Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Deferred compensation	$ 8,645	$ 226
Inventory adjustments	1,837
Accrued expenses	211
Credits	279
Net operating loss	3,120	949
Other		288
Total deferred tax assets	14,092	1,464
Deferred tax liabilities:
Property, plant and equipment	8,354	4,379
Intangibles	19,305	16,034
Inventory adjustment		175
Other	622
Total deferred tax liabilities	28,281	20,587
Net deferred tax liability	$ (14,188)	$ (19,123)

Income taxes - Consolidated Sta

Income taxes - Consolidated State NOL's Commence Expiry (Details) - Illinois [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Income Tax [Line Items]
NOL's carryforwards, Amount	$ 2,141
NOL's, Expire Commencing year	2039

Deferred compensation - Additio

Deferred compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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 and long-term incentive	$ (153)	$ 678	$ 22,830	$ 1,750	$ 2,713	$ 2,340	$ 1,365	$ 1,640	$ 25,105	$ 8,058	$ 5,397
Deferred compensation cash-based arrangements liability	$ 24,949				$ 13,351				24,949	13,351
Deferred Profit Sharing [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Deferred compensation and long-term incentive									10,476	1,647	1,133
Employees [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Deferred compensation and long-term incentive									$ 1,269	$ 856	$ 292
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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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.
Profit sharing, bonuses, and deferred compensation	$ (153)	$ 678	$ 22,830	$ 1,750	$ 2,713	$ 2,340	$ 1,365	$ 1,640	$ 25,105	$ 8,058	$ 5,397
Deferred Bonus [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Other deferred compensation arrangement liability					$ 1,846					1,846
Profit sharing, bonuses, and deferred compensation									$ 10,000	$ 1,712	$ 134
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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Self Funded Medical Benefits Insurance Disclosures [Line Items]
Estimated accrued liability	$ 1,316	$ 1,730
Reinsured limit of annual aggregate risk	19,208	$ 17,726	$ 16,176
Medical Insurance Plan One [Member]
Self Funded Medical Benefits Insurance Disclosures [Line Items]
Reinsured limit of annual risk per participant	225
Medical Insurance Plan Two [Member]
Self Funded Medical Benefits Insurance Disclosures [Line Items]
Reinsured limit of annual risk per participant	$ 200

Segments - Additional Informati

Segments - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019Segment
Segment Reporting [Abstract]
Number of operating segments	1

Segments - Schedule of Company'

Segments - Schedule of Company's Net Sales From External Customers (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 102,331	$ 128,511	$ 145,130	$ 143,732	$ 91,431	$ 84,338	$ 91,535	$ 87,221	$ 519,704	$ 354,526	$ 313,331
Operating Segments
Segment Reporting Information [Line Items]
Revenues									524,544	358,550	317,824
Intercompany Sales Elimination
Segment Reporting Information [Line Items]
Revenues									(4,839)	(4,024)	(4,493)
Outdoor Sports | Operating Segments
Segment Reporting Information [Line Items]
Revenues									7,181	6,862	7,896
Fabrication | Operating Segments
Segment Reporting Information [Line Items]
Revenues									334,340	147,099	129,387
Performance structures | Operating Segments
Segment Reporting Information [Line Items]
Revenues									71,881	84,231	87,742
Tube | Operating Segments
Segment Reporting Information [Line Items]
Revenues									71,108	80,715	65,440
Tank | Operating Segments
Segment Reporting Information [Line Items]
Revenues									$ 40,033	$ 39,641	$ 27,359

Fair value of financial instr_3

Fair value of financial instruments - Additional Information (Details) - USD ($) $ in Thousands	Dec. 14, 2018	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration	$ 6,076
Contingent consideration revaluation		$ (9,598)	$ 2,674	$ 869	$ (21)	$ (6,054)	$ (21)
Restatement Adjustment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration		9,598				0
Defiance Metal Products Co. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Business Acquisition, Effective Date							Dec. 14, 2018
Cash consideration including working capital adjustment, net of cash received	117,068		117,068			117,068
Contingent consideration	6,076	0	9,598	$ 6,924	$ 6,054		$ 6,054
Contingent consideration threshold		19,748
Contingent consideration revaluation						6,054
Defiance Metal Products Co. [Member] | Restatement Adjustment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration		$ 0	$ 9,598			$ 0
Defiance Metal Products Co. [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration	$ 10,000

Fair value of financial instr_4

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	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 24,949	$ 19,405
Contingent Consideration Payable [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		6,054
Fair Value, Inputs, Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,470	0
Fair Value, Inputs, Level 1 [Member] | Contingent Consideration Payable [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		0
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	22,479	0
Fair Value, Inputs, Level 2 [Member] | Contingent Consideration Payable [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		0
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	0	19,405
Fair Value, Inputs, Level 3 [Member] | Contingent Consideration Payable [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		6,054
Deferred Compensation [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	24,949	13,351
Deferred Compensation [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,470	0
Deferred Compensation [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	22,479	0
Deferred Compensation [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 0	$ 13,351

Fair value of financial instr_5

Fair value of financial instruments - Summary of Changes in Liabilities at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance as of December 31, 2018	$ 19,405
Payments	(75)
Transfer to level 1 and level 2 investments	(24,949)
Contingent Consideration Payable [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Contingent consideration revaluation	(6,054)
Deferred Compensation [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Deferred compensation adjustments	$ 11,673

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Changes in Contract Assets and Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Revenue From Contract With Customer [Abstract]
Contract asset, beginning balance	$ 2,318
Net Activity	(729)
Contract asset, ending balance	1,589
Contract liability, beginning balance	977
Net Activity	(63)
Contract liability, ending balance	$ 914

Revenue Recognition - Schedul_2

Revenue Recognition - Schedule of Disaggregation of Revenue by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Net sales	$ 102,331	$ 128,511	$ 145,130	$ 143,732	$ 91,431	$ 84,338	$ 91,535	$ 87,221	$ 519,704	$ 354,526	$ 313,331
Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									524,544	358,550	317,824
Intercompany Sales Elimination
Disaggregation Of Revenue [Line Items]
Net sales									(4,839)	(4,024)	(4,493)
Outdoor Sports | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									7,181	6,862	7,896
Fabrication | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									334,340	147,099	129,387
Performance structures | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									71,881	84,231	87,742
Tube | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									71,108	80,715	65,440
Tank | Operating Segments
Disaggregation Of Revenue [Line Items]
Net sales									$ 40,033	$ 39,641	$ 27,359

Temporary Equity - Schedule of

Temporary Equity - Schedule of Changes to Temporary Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Beginning, Balance	$ 102,989
Ending, Balance		$ 102,989
Redeemable Common Stock [Member]
Temporary Equity [Line Items]
Beginning, Balance	133,806	125,042
Change in redemption value of outstanding redeemable common shares, net		8,764
Transfer from temporary equity to common equity	(133,806)
Ending, Balance		133,806
Treasury Shares [Member]
Temporary Equity [Line Items]
Beginning, Balance	(57,659)	(49,826)
Purchase of treasury shares		(11,833)
Redistribution of Stockholders Share		4,000
Transfer from temporary equity to common equity	57,659
Ending, Balance		(57,659)
Retained Earnings [Member]
Temporary Equity [Line Items]
Beginning, Balance	26,842	17,671
Net Income	2,856	17,936
Change in redemption value of outstanding redeemable common shares, net		(8,764)
Transfer from temporary equity to common equity	$ (29,698)
Ending, Balance		$ 26,842

Common Equity - Additional Info

Common Equity - Additional Information (Details) - shares	Jun. 28, 2019	May 13, 2019
Class Of Stock [Line Items]
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 mentioned in Note 19, Temporary Equity, were removed effective with the IPO. Therefore, common shares were reclassified from temporary equity to permanent equity as of May 2019.
Common Stock [Member]
Class Of Stock [Line Items]
Shares cancelled	24,180,421
Common Stock [Member] | IPO [Member]
Class Of Stock [Line Items]
Additional commons stock was sold		6,402,209

Concentration of major custom_3

Concentration of major customers - Schedules of Major Customer Concentrations (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Customer A [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	15.10%	22.60%	20.20%
Customer A [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%	<10%
Customer B [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	13.50%	19.30%	19.80%
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		17.40%	14.70%
Concentration risk percentage	<10%
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	13.10%
Concentration risk percentage		<10%	<10%
Customer D [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage		12.60%
Concentration risk percentage	<10%
Customer E [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%	<10%	<10%
Customer E [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	13.50%	10.20%
Customer F [Member] | Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Concentration risk percentage	<10%	<10%	<10%
Customer F [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	10.40%
Concentration risk percentage		<10%

Stock based compensation - Addi

Stock based compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	4 Months Ended	12 Months Ended
	May 31, 2019	Apr. 30, 2019	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted		0
Share-based compensation arrangement by share-based payment award, award requisite service period	2 years
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected volatility rate			21.30%
Share-based compensation arrangement by share-based payment award, fair value assumptions, risk free interest rate			2.42%
Share-based compensation arrangement by share-based payment award, fair value assumptions, exercise price			$ 17
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected term			10 years
Share-based compensation arrangement by share-based payment award, fair value assumptions, method used			Black-Scholes option pricing model
Share options grant date fair value	$ 6.07
Share options grants during period	287,895
Stock options awarded, value	$ 1,748
Stock based compensation expense			$ 3,486
Stock options forfeitures during the year			14,416
Stock option exercises during period			0
Stock option expirations during period			0
Unrecognized stock based compensation expense			$ 3,720
Minimum [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	1 year
Maximum [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
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
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units grants during period	331,436
Restricted stock exercise price	$ 17
Restricted stock units forfeitures during the year			5,148
Restricted Stock Units (RSUs) [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards granted	$ 3,600
Restricted Stock Units (RSUs) [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards granted	$ 2,034

Valuation and qualifying acco_3

Valuation and qualifying accounts - Schedule Of Valuation And Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 801	$ 308
Additions	308	541
Deductions	583	48
Balance at end of period	$ 526	$ 801

Quarterly Results of Operatio_3

Quarterly Results of Operations (Unaudited) - Schedule of Unaudited Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 102,331	$ 128,511	$ 145,130	$ 143,732	$ 91,431	$ 84,338	$ 91,535	$ 87,221	$ 519,704	$ 354,526	$ 313,331
Cost of sales	98,297	113,941	124,595	124,153	81,035	71,517	75,986	75,411	460,986	303,948	278,594
Amortization of intangibles	2,677	2,677	2,677	2,677	1,279	939	939	939	10,706	4,096	3,756
Profit sharing, bonuses, and deferred compensation	(153)	678	22,830	1,750	2,713	2,340	1,365	1,640	25,105	8,058	5,397
Employee Stock Ownership Plan expense	953	1,500	1,500	1,500	1,000	1,000	1,000	1,000	5,453	4,000	4,000
Other selling, general and administrative expenses	5,170	6,068	7,506	6,723	3,841	2,855	2,713	2,867	25,466	12,276	12,158
Contingent consideration revaluation		(9,598)	2,674	869	(21)				(6,054)	(21)
Income (loss) from operations	(4,612)	13,245	(16,652)	6,060	1,585	5,687	9,532	5,364	(1,958)	22,169	9,426
Interest expense	(918)	(987)	(1,991)	(2,832)	(1,274)	(846)	(853)	(906)	(6,728)	(3,879)	(4,180)
Loss on extinguishment of debt			(154)		(226)		(588)		(154)	(814)
Income (loss) before taxes	(5,530)	12,258	(18,797)	3,228	85	4,841	8,091	4,458	(8,840)	17,476	5,246
Income tax benefit	(3,857)	2,512	(3,513)	769	(505)	17		29	(4,088)	(459)	0
Net income (loss) and comprehensive income (loss)	(1,673)	9,746	(15,284)	2,459	590	4,824	8,091	4,430	(4,753)	17,935	5,246
Earnings (loss) per share
Net income (loss) available to shareholders	$ (1,673)	$ 9,746	$ (15,284)	$ 2,459	$ 590	$ 4,824	$ 8,091	$ 4,430	$ (4,753)	$ 17,935	$ 5,246
Basic and diluted earnings (loss) per share	$ (0.08)	$ 0.49	$ (0.91)	$ 0.18	$ 0.04	$ 0.36	$ 0.56	$ 0.31	$ (0.27)	$ 1.29	$ 0.37
Basic and diluted weighted average shares outstanding	19,711,921	19,740,296	16,799,915	13,443,484	13,443,524	13,453,285	14,341,538	14,177,317	17,447,464	13,891,301	14,341,538
Tax-adjusted pro forma information
Net income (loss) available to shareholders	$ (1,673)	$ 9,746	$ (15,284)	$ 2,459	$ 590	$ 4,824	$ 8,091	$ 4,430	$ (4,753)	$ 17,935	$ 5,246
Pro forma provision for income taxes			103	70	175	1,254	2,104	1,130	173	4,663
Pro forma net income (loss)	$ (1,673)	$ 9,746	$ (15,387)	$ 2,389	$ 415	$ 3,570	$ 5,987	$ 3,300	$ (4,926)	$ 13,272	$ 5,246
Pro forma basic and diluted earnings (loss) per share	$ (0.08)	$ 0.49	$ (0.92)	$ 0.18	$ 0.03	$ 0.27	$ 0.42	$ 0.23	$ (0.28)	$ 0.96	$ 0.37
Basic and diluted weighted average shares outstanding	19,711,921	19,740,296	16,799,915	13,443,484	13,443,524	13,453,285	14,341,538	14,177,317	17,447,464	13,891,301	14,341,538