Limbach (LMB) 10-K 16 Mar 22 2021 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 15, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-36541
Entity Registrant Name	LIMBACH HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5399422
Entity Address, Address Line One	1251 Waterfront Place
Entity Address, Address Line Two	Suite 201
Entity Address, City or Town	Pittsburgh
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15222
City Area Code	412
Local Phone Number	359-2100
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	LMB
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 80.6
Entity Common Stock, Shares Outstanding		10,423,068
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement relating to the registrant’s 2022 Annual Meeting of Stockholders to be filed hereafter are incorporated by reference into Part III of this Annual Report on Form 10-K.
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001606163
Current Fiscal Year End Date	--12-31

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Name	Crowe LLP
Auditor Location	Atlanta, Georgia
Auditor Firm ID	173

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 14,476	$ 42,147
Restricted cash	113	113
Accounts receivable (net of allowance for doubtful accounts of $263 and $266 as of December 31, 2021 and 2020, respectively)	89,327	85,767
Contract assets	83,863	67,098
Advances to and equity in joint ventures, net	12	10
Other current assets	5,001	4,282
Total current assets	192,906	199,417
Property and equipment, net	21,621	19,700
Intangible assets, net	16,907	11,681
Goodwill	11,370	6,129
Operating lease right-of-use assets	20,119	18,751
Deferred tax asset	4,330	6,087
Other assets	259	392
Total assets	267,512	262,157
Current liabilities:
Current portion of long-term debt	9,879	6,536
Current operating lease liabilities	4,366	3,929
Accounts payable, including retainage	63,840	66,763
Contract liabilities	26,712	46,648
Accrued income taxes	501	1,671
Accrued expenses and other current liabilities	24,444	24,747
Total current liabilities	129,742	150,294
Long-term debt	29,816	36,513
Long-term operating lease liabilities	16,576	15,459
Other long-term liabilities	3,540	6,159
Total liabilities	179,674	208,425
Commitments and contingencies
Redeemable convertible preferred stock, net, par value $0.0001, $1,000,000 shares authorized, no shares issued and outstanding as of December 31, 2021 and December 31, 2020 ($0 redemption value as of December 31, 2021 and December 31, 2020)	0	0
STOCKHOLDERS’ EQUITY
Common Stock, Value, Issued	1	1
Additional paid-in capital	85,004	57,612
Retained earnings (accumulated deficit)	2,833	(3,881)
Total stockholders’ equity	87,838	53,732
Total liabilities and stockholders’ equity	267,512	262,157
Income Taxes Receivable, Current	$ 114	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Allowance for doubtful accounts	$ 263,000	$ 266,000
Common stock, par or stated value per share (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares, issued (in shares)	10,304,242	7,926,137
Common stock, shares, outstanding (in shares)	10,304,242	7,926,137
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Redeemable convertible preferred stock, shares issued (in shares)	0	0
Redeemable convertible preferred stock, shares outstanding (in shares)	0	0
Redeemable convertible preferred stock, redemption value	$ 0	$ 0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Revenue	$ 490,351	$ 568,209
Cost of revenue	404,441	486,823
Gross profit	85,910	81,386
Operating expenses:
Selling, general and administrative	71,436	63,601
Amortization of intangibles	484	630
Total operating expenses	71,920	64,231
Operating income	13,990	17,155
Other (expense) income:
Interest expense, net	(2,568)	(8,627)
Loss on debt extinguishment	(1,961)	0
Gain on sale of property and equipment	2	95
Gain (loss) on change in fair value of warrant liability	14	(1,634)
Total other expenses	(4,513)	(10,166)
Income before income taxes	9,477	6,989
Income tax provision	2,763	1,182
Net income	$ 6,714	$ 5,807
Net income per share:
Basic (in usd per share)	$ 0.67	$ 0.74
Diluted (in usd per share)	$ 0.66	$ 0.72
Weighted average number of shares outstanding:
Basic (in shares)	10,013,117	7,865,089
Diluted (in shares)	10,231,637	8,065,464

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Retained earnings (accumulated deficit)
Beginning Balance (in shares) at Dec. 31, 2019		7,688,958
Beginning Balance at Dec. 31, 2019	$ 46,870	$ 1	$ 56,557	$ (9,688)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued related to vested restricted stock units (in shares)		206,354
Shares issued related to vested restricted stock units	0
Tax withholding related to vested restricted stock units	(110)		(110)
Stock-based compensation	1,068		1,068
Proceeds related to employee stock purchase plan	97		97
Shares issued related to employee stock purchase plan (in shares)		30,825
Net income (loss)	5,807			5,807
Ending Balance (in shares) at Dec. 31, 2020		7,926,137
Ending Balance at Dec. 31, 2020	53,732	$ 1	57,612	(3,881)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued related to the sale of common stock (in shares)		2,051,025
Shares issued related to sale of common stock	22,773		22,773
Exercise of warrants (in shares)		172,874
Exercise of warrants	1,989		1,989
Shares issued related to vested restricted stock units (in shares)		129,138
Shares issued related to vested restricted stock units	0
Tax withholding related to vested restricted stock units	(191)		(191)
Stock-based compensation	2,601		2,601
Proceeds related to employee stock purchase plan	220		220
Shares issued related to employee stock purchase plan (in shares)		25,068
Net income (loss)	6,714			6,714
Ending Balance (in shares) at Dec. 31, 2021		10,304,242
Ending Balance at Dec. 31, 2021	$ 87,838	$ 1	$ 85,004	$ 2,833

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 6,714	$ 5,807
Adjustments to reconcile net income to cash (used in) provided by operating activities:
Depreciation and amortization	5,948	6,171
Noncash operating lease expense	4,268	4,033
Provision for doubtful accounts	198	100
Stock-based compensation expense	2,601	1,068
Loss on early debt extinguishment	1,961	0
Amortization of debt discount and issuance costs	280	2,157
Deferred income tax provision (benefit)	1,757	(1,301)
(Gain) loss on change in fair value of warrant liability	(14)	1,634
Gain on sale of property and equipment	(2)	(95)
Changes in operating assets and liabilities:
Accounts receivable	3,408	19,200
Contract assets	(15,054)	10,090
Other current assets	(555)	(115)
Accounts payable, including retainage	(5,578)	(19,504)
Contract liabilities	(20,399)	4,278
Prepaid income taxes	(114)	494
Accrued taxes payable	(1,170)	1,659
Accrued expenses and other current liabilities	(706)	4,713
Operating lease liabilities	(4,083)	(4,337)
Other long-term liabilities	(3,693)	3,763
Net cash (used in) provided by operating activities	(24,233)	39,815
Cash flows from investing activities:
Proceeds from sale of property and equipment	467	162
Jake Marshall Transaction, net of cash acquired	(18,977)	0
Advances to joint ventures	(2)	(2)
Purchase of property and equipment	(791)	(1,483)
Net cash used in investing activities	(19,303)	(1,323)
Cash flows from financing activities:
Proceeds from Wintrust and A&R Wintrust Term Loans	40,000	0
Proceeds from 2019 Revolving Credit Facility	0	7,250
Payments on 2019 Revolving Credit Facility	0	(7,250)
Prepayment penalty and other costs associated with debt extinguishment	(1,376)	0
Proceeds from sale of common stock	22,773	0
Proceeds from exercise of warrants	1,989	0
Payments on finance leases	(2,623)	(2,664)
Proceeds from contributions to employee stock purchase plan	323	191
Taxes paid related to net-share settlement of equity awards	(459)	(216)
Payments of debt issuance costs	(643)	0
Net cash provided by (used in) financing activities	15,865	(4,689)
(Decrease) increase in cash, cash equivalents and restricted cash	(27,671)	33,803
Cash, cash equivalents and restricted cash, beginning of year	42,260	8,457
Cash, cash equivalents and restricted cash, end of year	14,589	42,260
Noncash investing and financing transactions:
Earnout Payments associated with the Jake Marshall Transaction	3,089	0
Right of use assets obtained in exchange for new operating lease liabilities	5,417	1,096
Right of use assets obtained in exchange for new finance lease liabilities	1,296	2,624
Right of use assets disposed or adjusted modifying operating leases liabilities	219	621
Right of use assets disposed or adjusted modifying finance leases liabilities	0	(86)
Interest paid	2,549	6,467
Cash paid for income taxes	2,290	734
Wintrust And A&R Wintrust Term Loan
Cash flows from financing activities:
Repayments of Term Loans	(5,119)	0
2019 Refinancing Term Loan
Cash flows from financing activities:
Repayments of Term Loans	$ (39,000)	$ (2,000)

Business and Organization

Business and Organization	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Organization	Business and Organization Limbach Holdings, Inc. (the “Company,” “we” or “us”), a Delaware corporation headquartered in Pittsburgh, Pennsylvania, was formed on July 20, 2016 as a result of a business combination with Limbach Holdings LLC (“LHLLC”). The Company is an integrated building systems solutions firm whose expertise is in the design, modular prefabrication, installation, management and maintenance of heating, ventilation, air-conditioning (“HVAC”), mechanical, electrical, plumbing and controls systems. The Company provides comprehensive facility services consisting of mechanical construction, full HVAC service and maintenance, energy audits and retrofits, engineering and design build services, constructability evaluation, equipment and materials selection, offsite/prefabrication construction, and the complete range of sustainable building solutions. The Company's customers operate in diverse industries including, but not limited to, healthcare, life sciences, data centers, industrial and light manufacturing, entertainment, education and government. The Company operates primarily in the Northeast, Mid-Atlantic, Southeast, Midwest, and Southwestern regions of the United States. The Company operates in two segments, which were renamed as of January 1, 2021 to reflect the Company's two distinct approaches to its customer base and to better align with its owner direct strategy. The previously named Construction segment is now known as General Contractor Relationships (“GCR”); the previously named Service segment is now known as Owner Direct Relationships (“ODR”). The Company's operating segments are based on the relationship with its customers, (i) GCR, in which the Company generally manages new construction or renovation projects that involve primarily HVAC, plumbing, or electrical services awarded to the Company by general contractors or construction managers, and (ii) ODR, in which the Company provides maintenance or service primarily on HVAC, plumbing or electrical systems, building controls and specialty contracting projects direct to, or assigned by, building owners or property managers. This work is primarily performed under fixed price, modified fixed price, and time and material contracts over periods of typically less than two years. Impact of the COVID-19 Pandemic In March 2020, the World Health Organization declared the outbreak of the coronavirus disease 2019 (“COVID-19”) a global pandemic. The COVID-19 pandemic has caused significant disruption and volatility on a global scale resulting in, among other things, an economic slowdown, impacts to global supply chains, and the possibility of a continued economic recession. In response to the COVID-19 outbreak, national and local governments around the world instituted certain measures, including travel bans, restrictions on group events and gatherings, shutdowns of certain non-essential businesses, curfews, shelter-in-place orders, recommendations to practice social distancing and vaccine mandates. Certain governmental actions have abated over time, but remain applicable to Limbach's operations in various ways, often varying by state. In some instances, these orders continued to affect certain projects in our GCR and ODR segments during 2021. In limited instances, during fiscal 2020, projects chose to shutdown work irrespective of the existence or applicability of government action. In most markets, construction is considered an essential business and the Company continued to staff its projects and perform work during fiscal 2020 and into 2021, and most of the projects that were in progress at the time shutdowns commenced were restarted. The Company continues to actively manage its response to the COVID-19 pandemic in collaboration with relevant parties and, given that the situation surrounding COVID-19 remains fluid, a number of Company-wide measures undertaken in response to COVID-19 remain in effect to continue to promote the safety and health of its employees and customers. The Company continues to monitor the short and long term impacts of the pandemic. While our employees and customers have adapted to a new work environment and there continues to be scientific, societal and economic progress to address the effect of COVID-19, there remains significant uncertainty about the future impacts of the pandemic, including the potential effects on our operations. We remain cautiously optimistic about the markets in which we operate and the customers we serve; however, the continued spread of the virus may impact economic activity and could cause projects to be delayed or canceled, or we may experience access restrictions to our customers’ facilities and project sites. Supply chain disruptions, material shortages and escalating commodity prices as a result of COVID-19 are expected to continue into 2022. During the fourth quarter of 2021, the Company was impacted by supply chain issues delaying equipment delivery, which resulted in revenue being pushed to future periods. The impact of the COVID-19 pandemic on the Company’s vendors and the pricing and availability of materials or supplies utilized in the Company’s operations continues to evolve and may have an adverse impact on the Company’s operations in future periods. The ongoing effects of the pandemic, including decreased consumer confidence and economic instability, can make it extremely difficult for our customers, our vendors and us to accurately forecast and plan future business activities, and could cause constrained spending on our services, delays and a lengthening of our business development efforts, the demand for more

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) and based on the assumption that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities in the normal course of business. Principles of Consolidation References in these financial statements to the Company refer collectively to the accounts of Limbach Holdings, Inc. and its wholly-owned subsidiaries, including LHLLC, Limbach Facility Services LLC (“LFS”), Limbach Company LLC, Limbach Company LP, Harper Limbach LLC, Harper Limbach Construction LLC, Limbach Facility & Project Solutions LLC, Jake Marshall, LLC (“JMLLC”) and Coating Solutions, LLC (“CSLLC”) for all periods presented, unless otherwise indicated. All intercompany balances and transactions have been eliminated. Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements for assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of revenue and expenses during the reported period, and the accompanying notes. Management believes that its most significant estimates and assumptions have been based on reasonable and supportable assumptions and the resulting estimates are reasonable for use in the preparation of the consolidated financial statements. The Company’s significant estimates include estimates associated with revenue recognition on construction contracts, costs incurred through each balance sheet date, impairment of goodwill, intangibles, property and equipment, fair valuation in business combinations, insurance reserves, income tax valuation allowances, and contingencies. If the underlying estimates and assumptions upon which the consolidated financial statements are based change in the future, actual amounts may differ from those included in the accompanying consolidated financial statements. Cash and Cash Equivalents Cash and cash equivalents consist principally of currency on hand and demand deposits at commercial banks. The Company maintains demand accounts at several domestic banks. The Company's cash balances with financial institutions typically exceed the Federal Deposit Insurance Corporation (“FDIC”) coverage limit of $0.25 million. The Company's cash balances on deposit at December 31, 2021 and 2020, exceeded the balance insured by the FDIC by approximately $14.2 million and $41.9 million, respectively. Restricted Cash Restricted cash is cash held at a commercial bank in an imprest account held for the purpose of funding workers’ compensation and general liability claims against the Company. This amount is replenished either when depleted or at the beginning of each month. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Company’s consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: (in thousands) December 31, 2021 December 31, 2020 Cash and cash equivalents $ 14,476 $ 42,147 Restricted cash 113 113 Total cash, cash equivalents and restricted cash $ 14,589 $ 42,260 Accounts Receivable and Allowance for Doubtful Accounts The carrying value of the receivables, net of the allowance for doubtful accounts, represents their estimated net realizable value. Management provides for probable uncollectible accounts through a charge to earnings and a credit to the valuation account based on its assessment of the current status of individual accounts, type of service performed, and current economic conditions. Balances that are still outstanding after management has used reasonable collection efforts are written off through a charge to the valuation allowance and an adjustment of the account receivable. The majority of customer balances at each balance sheet date are collected within twelve months. As is common practice in the industry, the Company classifies all accounts receivable as current assets. Based on assessments by management, allowances for doubtful accounts were approximately $0.3 million at both December 31, 2021 and 2020. Joint Ventures The Company accounts for its participation in certain special purpose, project specific joint ventures under the equity method of accounting. The Company’s entry into these joint ventures is for the purpose of bidding, negotiating and completing specific projects. The Company and its joint venture partner(s) separately enter into their own sub-contracts with the joint venture for each party’s respective portion of the work. All revenue and expenses and the related contract assets and liabilities related to the Company’s sub-contract are recorded within the Company’s statements of operations and balance sheets, similarly to any other construction project. The joint venture itself does not accumulate any profits or losses, as the joint venture revenue is equal to the sum of the sub-contracts it issues to the joint venture partners. The voting power and management of the joint ventures are shared equally by the joint venture partners, qualifying these entities for joint venture treatment under GAAP. The shared voting power and management responsibilities allow the Company to exercise significant influence without controlling the joint venture entity. As such, the Company applies the equity method of accounting as defined in ASC Topic 323, Investments – Equity Method and Joint Ventures . Revenue Recognition The Company’s revenue is primarily derived from construction-type and service contracts that generally range from six months to two years. The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers . ASC Topic 606 provides for a five-step model for recognizing revenue from contracts with customers as follows: 1. Identify the contract 2. Identify performance obligations 3. Determine the transaction price 4. Allocate the transaction price 5. Recognize revenue Identify the contract with a customer. A contract with a customer exists when: (a) the parties have approved the contract and are committed to perform their respective obligations, (b) the rights of the parties can be identified, (c) payment terms can be identified, (d) the arrangement has commercial substance, and (e) collectability of consideration is probable. Judgment is required when determining if the contractual criteria are met, specifically in the earlier stages of a project when a formally executed contract may not yet exist. In these situations, the Company evaluates all relevant facts and circumstances, including the existence of other forms of documentation or historical experience with our customers that may indicate a contractual agreement is in place and revenue should be recognized. In determining if the collectability of consideration is probable, the Company considers the customer’s ability and intention to pay such consideration through an evaluation of several factors, including an assessment of the creditworthiness of the customer and our prior collection history with such customer. Identify the performance obligations in the contract . At contract inception, the Company assesses the goods or services promised in a contract and identifies, as a separate performance obligation, each distinct promise to transfer goods or services to the customer. The identified performance obligations represent the “unit of account” for purposes of determining revenue recognition. In order to properly identify separate performance obligations, the Company applies judgment in determining whether each good or service provided is: (a) capable of being distinct, whereby the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer, and (b) distinct within the context of the contract, whereby the transfer of the good or service to the customer is separately identifiable from other promises in the contract. Determine the transaction price. The transaction price represents the amount of consideration to which the Company expects to be entitled in exchange for transferring promised goods or services to our customers. The consideration promised within a contract may include fixed amounts, variable amounts, or both. To the extent the performance obligation includes variable consideration, the Company estimates the amount of variable consideration to be included in the transaction price utilizing one of two prescribed methods, depending on which method better predicts the amount of consideration to which the entity will be entitled. Such methods include: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current, and estimates of future performance. The expected value method is typically utilized in situations where a contract contains a large number of possible outcomes while the most likely amount method is typically utilized in situations where a contract has only two possible outcomes. Variable consideration is included in the transaction price only to the extent it is probable, in the Company’s judgment, that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur when the uncertainty associated with the variable consideration is subsequently resolved. This threshold is referred to as the variable consideration constraint. In assessing whether to apply the variable consideration constraint, the Company considers if factors exist that could increase the likelihood or the magnitude of a potential reversal of revenue, including, but not limited to, whether: (a) the amount of consideration is highly susceptible to factors outside of the Company’s influence, such as the actions of third parties, (b) the uncertainty surrounding the amount of consideration is not expected to be resolved for a long period of time, (c) the Company’s experience with similar types of contracts is limited or that experience has limited predictive value, (d) the Company has a practice of either offering a broad range of price concessions or changing the payment terms and conditions of similar contracts in similar circumstances, and (e) the contract has a large number and broad range of possible consideration amounts. Pending change orders represent one of the most common forms of variable consideration included within contract value and typically represent contract modifications for which a change in scope has been authorized or acknowledged by our customer but the final adjustment to contract price is yet to be negotiated. In estimating the transaction price for pending change orders, the Company considers all relevant facts, including documented correspondence with the customer regarding acknowledgment of and/or agreement with the modification, as well as historical experience with the customer or similar contractual circumstances. Based upon this assessment, the Company estimates the transaction price, including whether the variable consideration constraint should be applied. Contract claims are another form of variable consideration which is common within our industry. Claim amounts represent revenue that has been recognized for contract modifications that are not submitted or are in dispute as to both scope and price. In estimating the transaction price for claims, the Company considers all relevant facts available. However, given the uncertainty surrounding claims, including the potential long-term nature of dispute resolution and the broad range of possible consideration amounts, there is an increased likelihood that any additional contract revenue associated with contract claims is constrained. The resolution of claims involves negotiations and, in certain cases, litigation. In the event litigation costs are incurred by us in connection with claims, such litigation costs are expensed as incurred, although we may seek to recover these costs. Allocate the transaction price to performance obligations in the contract. For contracts that contain multiple performance obligations, the Company allocates the transaction price to each performance obligation based on a relative standalone selling price. The Company determines the standalone selling price based on the price at which the performance obligation would have been sold separately in similar circumstances to similar customers. If the standalone selling price is not observable, the Company estimates the standalone selling price taking into account all available information such as market conditions and internal pricing guidelines. In certain circumstances, the standalone selling price is determined using an expected profit margin on anticipated costs related to the performance obligation. Recognize revenue as performance obligations are satisfied. Throughout the execution of our construction-type contracts, the Company recognizes revenue with the continuous transfer of control to the customer. The customer typically controls the asset under construction by either contractual termination clauses or by the Company’s rights to payment for work already performed on the asset under construction that does not have an alternative use for the Company. Because control transfers over time, revenue is recognized to the extent of progress towards completion of the performance obligations. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services provided. The Company generally uses the cost-to-cost method for its contracts, which measures progress towards completion for each performance obligation based on the ratio of costs incurred to date to the total estimated costs at completion for the respective performance obligation. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Revenue, including estimated profits, is recorded proportionately as costs are incurred. Cost of operations includes labor, materials, subcontractor costs, and other direct and indirect costs, including depreciation and amortization. Certain construction-type contracts include retention provisions to provide assurance to our customers that we will perform in accordance with the contract terms and are not considered a financing benefit. The balances billed but not paid by customers pursuant to these provisions generally become due upon completion and acceptance of the project work by the customer. The Company has determined there are no significant financing components in our contracts during the years ended December 31, 2021 and 2020. For our service-type contracts, revenue is also generally recognized over time as the customer simultaneously receives and consumes the benefits of our performance as we perform the service. For our fixed price service-type contracts with specified service periods, revenue is generally recognized on a straight-line basis over such service period when our inputs are expended evenly, and the customer receives and consumes the benefits of our performance throughout the contract term. Due to uncertainties inherent in the estimation process, it is possible that estimates of costs to complete a performance obligation will be revised in the near-term. For those performance obligations for which revenue is recognized using a cost-to-cost input method, changes in total estimated costs, and related progress towards complete satisfaction of the performance obligation, are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. When the current estimate of total costs for a performance obligation indicate a loss, a provision for the entire estimated loss on the unsatisfied performance obligation is made in the period in which the loss becomes evident. Costs to fulfill our contracts (“pre-bid costs”) that are not expected to be recovered from the customer are expensed as incurred and included in selling, general and administrative expenses on our consolidated statements of operations. In accordance with industry practice, we classify as current all assets and liabilities relating to the performance of contracts. See Note 4 – Revenue from Contracts with Customers for further information. Changes in Estimates on Construction Contracts The accuracy of our revenue and profit recognition in a given period depends on the accuracy of our estimates of the cost to complete each project. There are a number of factors that can contribute to changes in estimates of contract cost and profitability. The most significant of these include: • The completeness and accuracy of the original bid; • costs associated with scope changes; • expected, or actual, resolution terms for claims; • achievement of contract incentives; • changes in costs of labor and/or materials; • extended overhead and other costs due to owner, weather and other delays; • subcontractor performance issues; • changes in productivity expectations; • site conditions that differ from those assumed in the original bid; • changes from original design on design-build projects; • the availability and skill level of workers in the geographic location of the project; • a change in the availability and proximity of equipment and materials; • our ability to fully and promptly recover on claims and back charges for additional contract costs, and • the customer's ability to properly administer the contract. Subsequent to the inception of a construction-type contract in our GCR and ODR segments, the transaction price could change for various reasons, including the executed or estimated amount of change orders and unresolved contract modifications and claims to or from owners. Changes that are accounted for as an adjustment to existing performance obligations are allocated on the same basis at contract inception. Otherwise, changes are accounted for as separate performance obligation(s) and the separate transaction price is allocated. Changes are made to the transaction price from unapproved change orders to the extent the amount can be reasonably estimated and recovery is probable. On certain projects, we have submitted and have pending unresolved contract modifications and claims to recover additional costs and the associated profit, if applicable, to which we believe we are entitled under the terms of contracts with customers, subcontractors, vendors or others. The owners or their authorized representatives and/or other third parties may be in partial or full agreement with the modifications or claims, or may have rejected or disagree entirely or partially as to such entitlement. Changes are made to the transaction price from affirmative claims with customers to the extent that additional revenue on a claim settlement with a customer is probable and estimable. A reduction to costs related to claims with non-customers with whom we have a contractual arrangement (“back charges”) is recognized when the estimated recovery is probable and estimable. Recognizing claims and back charge recoveries requires significant judgments of certain factors including, but not limited to, dispute resolution developments and outcomes, anticipated negotiation results, and the cost of resolving such matters. The foregoing factors, as well as the stage of completion of contracts in process and the mix of contracts at different margins may cause fluctuations in gross profit and gross profit margin from period to period. Generally, if the contract is at an early stage of completion, the current period impact is smaller than if the same change in estimate is made to the contract at a later stage of completion. Significant changes in cost estimates, particularly in our larger, more complex projects have had, and can in future periods have, a significant effect on our profitability. Management evaluates changes in estimates on a contract by contract basis and discloses significant changes, if material, in the notes to the consolidated financial statements. The cumulative catch-up method is used to account for revisions in estimates. Provisions for estimated losses on uncompleted contracts are recognized in the period in which such losses are determined. Goodwill and Impairment of Long-Lived Assets Goodwill is evaluated for impairment at least annually or whenever events or changes in circumstance indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company may perform either a qualitative assessment of potential impairment or proceed directly to a quantitative assessment of potential impairment. The Company's qualitative assessment of potential impairment may result in the determination that a quantitative impairment analysis is not necessary. Under this elective process, the Company assesses qualitative factors to determine whether the existence of events or circumstances leads the Company to determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If after assessing the totality of events or circumstances, the Company determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then a quantitative assessment is not required. However, if the Company concludes otherwise, a quantitative impairment analysis is performed. If the Company chooses not to perform a qualitative assessment, or if it chooses to perform a qualitative assessment but is unable to qualitatively conclude that no impairment has occurred, then the Company will perform a quantitative assessment. In the case of a quantitative assessment, the Company estimates the fair value of the reporting unit with which the goodwill is associated and compares it to the carrying value. If the estimated fair value of a reporting unit is less than its carrying value, an impairment charge is recognized for the excess of the reporting unit's carrying value over its fair value. See Note 5 – Goodwill and Intangible Assets for further detail. The Company evaluates long-lived assets for impairment when events or changes in circumstances indicate, in management's judgment, that the carrying value of such assets may not be recoverable. With respect to property, plant and equipment and finite lived intangibles, asset recoverability is measured by comparing the carrying value of the asset or asset group with its expected future pre-tax undiscounted cash flows. These cash flow estimates require the Company to make projections and assumptions for many years into the future for pricing, demand, competition, operating cost and other factors. If the carrying amount exceeds the expected future undiscounted cash flows, the Company recognizes an impairment equal to the excess of carrying value over fair value as determined by quoted market prices in active markets or present value techniques if quotes are unavailable. The determination of the fair value using present value techniques requires the Company to make projections and assumptions regarding the probability of a range of outcomes and the rates of interest used in the present value calculations. Any changes the Company makes to these projections and assumptions could result in significant revisions to its evaluations of recoverability and the recognition of additional impairments. See Note 5 – Goodwill and Intangible Assets for further discussion on impairments of long-lived assets. Intangible Assets The Company’s indefinite-lived intangible assets associated with its trade name are evaluated for impairment at least annually or more frequently if events or circumstances indicate that it is more likely than not that the fair value of its indefinite-lived intangible asset are less than their carrying amount. The Company’s customer relationship-related intangible assets are amortized over the period the Company expects to receive the related economic benefit based upon estimated future net cash flows and its favorable leasehold interest-related intangible assets are amortized on a straight-line basis over the remaining lease terms. As a result of the Jake Marshall Transaction (defined in Note 3), the Company recognized, in the aggregate, an additional $5.7 million of intangible assets associated with customer relationships with third-party customers, the acquired trade name and acquired backlog. The Jake Marshall-related intangible assets were recorded under the acquisition method of accounting at their estimated fair values at the acquisition date. See Note 3 – Acquisitions for further discussion of the Company’s acquired intangible assets as a result of the Jake Marshall Transaction. See Note 5 – Goodwill and Intangible Assets for further discussion of the Company’s intangible assets. Property and Equipment, net Property and equipment, with the exception of our fleet vehicle finance leases, are recorded at cost and depreciated on a straight-line basis over their estimated useful lives. For buildings and leasehold improvements, the Company’s useful lives range from 5 years to 40 years; for machinery and equipment, useful lives range from 3 years to 10 years. Expenditures for maintenance and repairs are expensed as incurred. Leasehold improvements for our real estate operating leases are amortized over the lesser of the term of the related lease or the estimated useful lives of the improvements. The following table summarizes the Company’s property and equipment: ( in thousands ) December 31, 2021 December 31, 2020 Land and improvements $ 400 $ 400 Buildings and leasehold improvements 10,721 7,751 Machinery and equipment 24,600 21,647 Finance leases - vehicles (1) 10,771 11,505 Gross property and equipment 46,492 41,303 Less: Accumulated amortization on finance leases (5,855) (5,263) Less: Accumulated depreciation (19,016) (16,340) Property and equipment, net of accumulated amortization and depreciation (2) $ 21,621 $ 19,700 (1) See additional information provided in Note 13 – Leases. (2) Includes net property and equipment of approximately $5.6 million for the year ended December 31, 2021 related to assets acquired in the Jake Marshall Transaction. Depreciation and amortization expense on property and equipment was $5.5 million for both the years ended December 31, 2021 and 2020. Leases A lease contract conveys the right to use an underlying asset for a period of time in exchange for consideration. At inception, we determine whether a contract contains a lease by determining if there is an identified asset and if the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. Leases are classified as either operating or finance, based on our evaluation of certain criteria. With the exception of short-term leases (leases with an initial term of 12 months or less), at lease commencement, we measure and record a lease liability equal to the present value of the remaining lease payments, generally discounted using quoted borrowing rates on our secured debt as the implicit rate is not readily determinable on many of our real estate operating leases. For our fleet vehicles classified as financing leases, we use the stated interest rate in the lease. On the lease commencement date, the amount of the right-of-use (“ROU”) assets consist of the following: • the amount of the initial measurement of the lease liability; • any lease payment made at or before the commencement date, minus any lease incentives received; and • any initial direct costs incurred. Most of our operating lease contracts have the option to extend or renew. We assess the option for individual leases, and we generally consider the base term to be the term of lease contracts. See Note 13 – Leases for additional information. We periodically evaluate whether events and circumstances have occurred that indicate that the remaining balances of our ROU assets may not be recoverable. We use estimates of future undiscounted cash flows, as well as other economic and business factors, to assess the recoverability of these assets. Deferred Financing Costs and Debt Discount Deferred financing costs are deferred and amortized to interest expense using the effective interest rate method over the term of the related long-term debt agreement, and the straight-line method for the revolving credit agreement. Debt issuance costs related to the issuance and/or extension, as applicable, of the Company’s term loans are reflected as a direct reduction from the carrying amount of long-term debt. Debt issuance costs related to revolving credit facilities are capitalized and reflected as an other asset. Prior to their extinguishment, the allocated fair value of the CB Warrants (defined in Note 7 ) were recorded as a debt discount and were accreted over the expected term of the debt as interest expense. See Note 7 – Debt for additional information. Stock-Based Compensation Stock-based compensation awards granted to executives, employees, and non-employee directors are measured at fair value and recognized as an expense. For awards with service conditions only, the Company recognizes compensation expense on a graded vesting basis over the requisite service period for each separately vesting tranche of the award based on the closing market price of the Company’s common stock at the grant date. For awards with service and performance conditions, the Company recognizes compensation expense based on the closing market price of the Company’s common stock at the grant date using the straight-line method over the requisite service period. Estimates of compensation expense for an award with performance conditions are based on the probable outcome of the performance conditions. The cumulative effect of changes in the probability outcomes are recorded in the period in which the changes occur. For awards with market-based conditions (“MRSUs”), the Company uses a Monte Carlo simulation model to estimate the grant-date fair value. The fair value related to market-based awards is recorded as compensation expense using the graded vesting method regardless of whether the market condition is achieved or not. The Company has elected to account for forfeitures as they occur to determine the amount of compensation expense to be recognized each period. See also Note 16 – Management Incentive Plans for further information. Income Taxes The provision for income taxes includes federal, state and local taxes. The Company accounts for income taxes in accordance with ASC Topic 740 - Income Taxes , which requires the use of the asset and liability method. Under this method, deferred tax assets and liabilities and income or expense is recognized for the expected future tax consequences of temporary differences between the financial statement carrying values and their respective tax bases, using enacted tax rates expected to be applicable in the years in which the temporary differences are expected to reverse. Changes in tax rates are recorded to deferred tax assets and liabilities and reflected in the provision for income taxes during the period that includes the enactment date. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of the deferred tax assets will not be realized. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected, scheduling of anticipated reversals of taxable temporary differences, and considering prudent and feasible tax planning strategies. Any interest or penalties incurred related to unrecognized tax benefits are recorded as tax expense in the provision for income tax expense line item of the accompanying consolidated statements of operations. The consolidated financial statements reflect expecte

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions	Acquisitions Jake Marshall Transaction On December 2, 2021 (the “Effective Date”), the Company and LFS entered into a Membership Interest Purchase Agreement (the “Purchase Agreement”) with JMLLC, CSLLC, a Tennessee limited liability company (together with JMLLC, the “Acquired Companies” and each an “Acquired Company”) and the owners of the Acquired Companies (collectively, the “Sellers”), pursuant to which LFS purchased all of the outstanding membership interests in the Acquired Companies from the Sellers (the transactions contemplated by the Purchase Agreement collectively being the “Jake Marshall Transaction”). The Jake Marshall Transaction closed on the Effective Date. As a result of the Jake Marshall Transaction, each of the Acquired Companies became wholly-owned indirect subsidiaries of the Company. The acquisition expands the Company’s market share within its existing product and service lines. Total consideration paid by the Company for the Jake Marshall Transaction was $21.3 million (the “Closing Purchase Price”), consisting of cash paid to the Sellers, net of adjustments for working capital. Of the consideration paid to the Sellers, $1.0 million is being held in escrow for indemnification purposes. The purchase price is subject to customary post-closing adjustments. In addition, the Sellers may receive up to an aggregate of $6.0 million in cash, consisting of two tranches of $3.0 million, as defined in the Purchase Agreement, if the gross profit of the Acquired Companies equals or exceeds $10.0 million in (i) the approximately 13 month period from closing through December 31, 2022 (the “2022 Earnout Period”) or (ii) fiscal year 2023 (the “2023 Earnout Period”), respectively (collectively, the “Earnout Payments”). To the extent, however, that the gross profit of the Acquired Companies is less than $10.0 million, but exceeds $8.0 million, during any of the 2022 Earnout Period or 2023 Earnout Period, the $3.0 million amount will be prorated for such period. The Company recorded $0.6 million in acquisition-related expenses related to the Jake Marshall Transaction during the year ended December 31, 2021 associated with professional fees, which are included in selling, general and administrative expense in the consolidated statement of operations. Allocation of Purchase Price. The Jake Marshall Transaction was accounted for as a business combination using the acquisition method. The following table summarizes the final purchase price and estimated fair values of assets acquired and liabilities assumed as of the Effective Date, with any excess of purchase price over estimated fair value of the identified net assets acquired recorded as goodwill. As a result of the acquisition, the Company recognized $5.2 million of goodwill, all of which was allocated to the ODR reporting unit and fully deductible for tax purposes. Such goodwill primarily related to anticipated future earnings. The following table summarizes the allocation of the fair value of the assets and liabilities of the Jake Marshall Transaction as of the Effective Date by the Company. (in thousands) Purchase Price Allocation Consideration: Cash $ 21,313 Earnout provision 3,089 Total Consideration 24,402 Fair value of assets acquired: Cash and cash equivalents 2,336 Accounts receivable 7,165 Contract assets 1,711 Other current assets 164 Property and equipment 5,762 Intangible assets 5,710 Amount attributable to assets acquired 22,848 Fair value of liabilities assumed: Accounts payable, including retainage 2,655 Accrued expenses and other current liabilities 570 Contract liabilities 462 Amount attributable to liabilities assumed 3,687 Goodwill $ 5,241 For working capital items, such as cash and cash equivalents, accounts receivable, other current assets, accounts payable and accrued expenses and other current liabilities, the Acquired Companies’ carrying value was assumed to represent the fair value of these assets due to the current nature of the assets and liabilities. There was no difference between the contract value and fair value of accounts receivable acquired. The estimated fair value of property and equipment, generally consisting of leasehold improvements and machinery and equipment, was estimated using the cost approach. Significant unobservable inputs in the estimate of fair value under this approach included management's assumptions about the replacement costs for similar assets, the relative age of the acquired assets and any potential economic or functional obsolescence associated with the acquired assets. As a result, the estimated fair value of the property and equipment represented a Level 3 fair value measurement. As part of the purchase price allocation, the Company identified certain definite-lived intangible assets associated with customer relationships with third-party customers, the acquired trade name and acquired backlog. The fair value of the customer relationships with third-party customers and acquired backlog was determined using the multi-period excess earning method under the income approach. The multi-period excess earnings method is a variation of the discounted cash-flow analysis, which isolates the cash flows that can be associated with a single intangible asset and measures fair value by discounting it back to present value. The fair value of the acquired trade name intangible asset was determined using an income approach, specifically known as the relief-from-royalty method. This method requires identifying the future revenue that would be generated by the trademark, multiplying it by a royalty rate deemed to be avoided through ownership of the asset and discounting the projected royalty savings amounts back to the acquisition date. The royalty rate used in the valuation was based on a consideration of market rates for similar categories of assets. Some of the more significant estimates and assumptions inherent in determining the fair value of the identifiable intangible assets are associated with forecasting cash flows and profitability, which represent Level 3 inputs. The Company calculates amortization of the acquired intangible assets using the straight-line method over the estimated useful lives of each acquired intangible assets. Amortization expense recorded in the consolidated statements of operations for the period from December 2, 2021 to December 31, 2021 was approximately $0.1 million. The estimated annual amortization expense over the next five years is approximately $1.3 million, $1.0 million, $0.7 million, $0.7 million and $0.7 million. Intangible assets, net as of December 31, 2021 are detailed below. (in thousands) Gross Carrying Amount Accumulated Amortization Net Intangible Assets Weighted Average Useful Life (Years) Trade name $ 1,150 $ (15) $ 1,135 6.2 Customer relationships - GCR 570 (6) 564 7.1 Customer relationships - ODR 3,050 (34) 3,016 7.6 Backlog - GCR 260 (14) 246 1.6 Backlog - ODR 680 (36) 644 1.6 Total $ 5,710 $ (105) $ 5,605 6.3 The aforementioned contingent Earnout Payments are associated with the achievement of specified gross profit milestones. The Company estimated that the fair value of the Earnout Payments was approximately $3.1 million at the date of acquisition, of which the entire balance was included in other long-term liabilities in the Company’s consolidated balance sheet as of December 31, 2021. The Company determined the initial fair value of the Earnout Payments based on the Monte Carlo Simulation method, which represented a Level 3 measurement. As of the Effective Date, the Earnout Payments associated with the Jake Marshall Transaction were valued utilizing a discount rate of 6.83%. The discount rate was calculated using the build-up method with a risk-free rate commensurate with the term of the Earnout Payments based on the U.S. Treasury Constant Maturity Yield. Subsequent to the Effective Date, the Earnout Payments are re-measured at fair value each reporting period. Changes in the estimated fair value of the contingent payments subsequent to the acquisition date are recognized immediately in earnings. Unaudited Pro Forma Information. The following unaudited pro forma combined financial information presents the Company's results as though the Jake Marshall Transaction had been completed at January 1, 2020. The pro forma combined financial information has been included for comparative purposes and is not necessarily indicative of the results that might have actually occurred had the Jake Marshall Transaction taken place on January 1, 2020; furthermore, the financial information is not intended to be a projection of future results. Year Ended December 31, (in thousands) (unaudited) 2021 2020 Pro forma revenue $ 523,479 $ 599,013 Pro forma net income $ 5,392 $ 4,310 Pro forma EPS (basic) $ 0.54 $ 0.55 Pro forma EPS (diluted) $ 0.53 $ 0.53

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with CustomersThe Company generates revenue principally from fixed-price construction contracts to deliver HVAC, plumbing, and electrical construction services to its customers. The duration of its contracts generally ranges from six months to two years. Revenue from fixed price contracts is recognized on the cost-to-cost method, measured by the relationship of total cost incurred to total estimated contract costs. Revenue from time and materials contracts is recognized as services are performed. The Company believes that its extensive experience in HVAC, plumbing, and electrical projects, and its internal cost review procedures during the bidding process, enable it to reasonably estimate costs and mitigate the risk of cost overruns on fixed price contracts. The Company generally invoices customers on a monthly basis, based on a schedule of values that breaks down the contract amount into discrete billing items. Costs and estimated earnings in excess of billings on uncompleted contracts are recorded as a contract asset until billable under the contract terms. Billings in excess of costs and estimated earnings on uncompleted contracts are recorded as a contract liability until the related revenue is recognizable. The Company classifies contract assets and liabilities that may be settled beyond one year from the balance sheet date as current, consistent with the length of time of the Company’s project operating cycle. Contract assets Contract assets include amounts due under retainage provisions and costs and estimated earnings in excess of billings. The components of the contract asset balances as of the respective dates were as follows: (in thousands) December 31, 2021 December 31, 2020 Change Contract assets Costs in excess of billings and estimated earnings $ 47,447 $ 31,894 $ 15,553 Retainage receivable 36,416 35,204 1,212 Total contract assets $ 83,863 $ 67,098 $ 16,765 Retainage receivable represents amounts invoiced to customers where payments have been partially withheld, typically 10%, pending the completion of certain milestones, satisfaction of other contractual conditions or the completion of the project. Retainage agreements vary from project to project and balances could be outstanding for several months or years depending on a number of circumstances such as contract-specific terms, project performance and other variables that may arise as the Company makes progress towards completion. Contract assets represent the excess of contract costs and profits (or contract revenue) over the amount of contract billings to date and are classified as a current asset. Contract assets result when either: (1) the appropriate contract revenue amount has been recognized over time in accordance with ASC Topic 606, but a portion of the revenue recorded cannot be currently billed due to the billing terms defined in the contract, or (2) costs are incurred related to certain claims and unapproved change orders. Claims occur when there is a dispute regarding both a change in the scope of work and the price associated with that change. Unapproved change orders occur when a change in the scope of work results in additional work being performed before the parties have agreed on the corresponding change in the contract price. The Company routinely estimates recovery related to claims and unapproved change orders as a form of variable consideration at the most likely amount it expects to receive and to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Claims and unapproved change orders are billable upon the agreement and resolution between the contractual parties and after the execution of contractual amendments. Increases in claims and unapproved change orders typically result from costs being incurred against existing or new positions; decreases normally result from resolutions and subsequent billings. The current estimated net realizable value on such items as recorded in contract assets and contract liabilities in the consolidated balance sheets was $38.1 million and $33.6 million as of December 31, 2021 and 2020, respectively. The Company anticipates that the majority of such amounts will be approved or executed within one year. The resolution of those claims and unapproved change orders that may require litigation or other forms of dispute resolution proceedings may delay the timing of billing beyond one year. Contract liabilities include billings in excess of contract costs and provisions for losses. The components of the contract liability balances as of the respective dates were as follows: (in thousands) December 31, 2021 December 31, 2020 Change Contract liabilities Billings in excess of costs and estimated earnings $ 26,293 $ 46,020 $ (19,727) Provisions for losses 419 628 (209) Total contract liabilities $ 26,712 $ 46,648 $ (19,936) Billings in excess of costs represent the excess of contract billings to date over the amount of contract costs and profits (or contract revenue) recognized to date. The balance may fluctuate depending on the timing of contract billings and the recognition of contract revenue. Provisions for losses are recognized in the consolidated statements of operations at the uncompleted performance obligation level for the amount of total estimated losses in the period that evidence indicates that the estimated total cost of a performance obligation exceeds its estimated total revenue. The net underbilling (overbilling) position for contracts in process consisted of the following: (in thousands) December 31, 2021 December 31, 2020 Revenue earned on uncompleted contracts $ 758,450 $ 752,564 Less: Billings to date (737,296) (766,690) Net underbilling (overbilling) $ 21,154 $ (14,126) (in thousands) December 31, 2021 December 31, 2020 Costs in excess of billings and estimated earnings $ 47,447 $ 31,894 Billings in excess of costs and estimated earnings (26,293) (46,020) Net underbilling (overbilling) $ 21,154 $ (14,126) Revisions in Contract Estimates The following table summarizes the Company’s recorded revisions in its contract estimates for certain GCR and ODR projects for the years ended December 31, 2021 and 2020 (includes material gross profit changes of $0.25 million or more). For the Years Ended December 31, 2021 2020 (in thousands except project count ) Project count Project count Gross profit write-ups: GCR $ 5,663 12 $ 1,654 3 ODR — — — — Total gross profit write-ups $ 5,663 12 $ 1,654 3 Gross profit write-downs: GCR $ (5,958) 8 $ (10,379) 15 ODR (332) 1 — — Total gross profit write-downs $ (6,290) 9 $ (10,379) 15 Total gross profit write-downs, net $ (627) $ (8,725) During the year ended December 31, 2021, the Company recorded total net gross profit write-ups, regardless of materiality, of $0.4 million compared to total net gross profit write-downs, regardless of materiality, of $7.9 million for the year ended December 31, 2020. Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for which work has not been performed and exclude unexercised contract options. The Company’s remaining performance obligations includes projects that have a written award, a letter of intent, a notice to proceed or an agreed upon work order to perform work on mutually accepted terms and conditions. As of December 31, 2021, the aggregate amount of the transaction prices allocated to the remaining performance obligations of the Company's GCR and ODR segment contracts were $337.2 million and $81.2 million, respectively. The Company currently estimates that 65% and 52% of our GCR and ODR segment remaining performance obligations as of December 31, 2021, respectively, will be recognized as revenue during 2022, with the substantial majority of remaining performance obligations to be recognized within 24 months, although the timing of the Company’s performance is not always under its control. Additionally, the difference between remaining performance obligations and backlog is due to the exclusion of a portion of the Company’s ODR agreements under certain contract types from the Company’s remaining performance obligations as these

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill The Company tests its goodwill and indefinite-lived intangible asset allocated to its reporting units for impairment annually on October 1, or more frequently if events or circumstances indicate that it is more likely than not that the fair value of its reporting units and indefinite-lived intangible asset are less than their carrying amount. The Company has the option to assess goodwill for possible impairment by performing a qualitative analysis to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative assessment is performed if the qualitative assessments results in a more-likely-than-not determination or if a qualitative assessment is not performed. During the third quarter of 2021, the Company identified impairment indicators in the form of significant declines in the stock price of the Company's common shares and corresponding market capitalization. Management considered these declines as indicators that the fair value of the ODR reporting unit may have been below its carrying amount, and the performance of an interim quantitative goodwill impairment assessment was required. In estimating the fair value of the ODR reporting unit, the Company used a combination of the income approach and the market approach. The Company used the income approach’s discounted cash flow method, which applies significant inputs not observable in the public market (Level 3), including estimates and assumptions related to the use of an appropriate discount rate, future cash flows generated from existing work and new awards, projected operating margins and changes in working capital. The Company used the market approach’s comparable company method. The comparable company method evaluates the value of a company using metrics of other businesses of similar size and industry. As a result of the interim assessment, the Company determined that the fair value of the ODR reporting unit was greater than its respective carrying value. The impairment assessment concluded significant headroom of $33.3 million, or 169%, for the ODR reporting unit. No impairment to goodwill was recorded as a result of the interim assessment. The Company believes the estimates and assumptions used in estimating its reporting units’ fair values are reasonable and appropriate; however, different assumptions and estimates could materially affect the calculated fair value of the ODR reporting unit and the resulting conclusions on impairment of goodwill, which could materially affect the Company’s results of operations and financial position. Additionally, actual results could differ from these estimates and assumptions may not be realized. In addition, no impairment losses were identified as a result of our qualitative assessments during the year ended December 31, 2020. The following table summarizes the carrying amount of goodwill associated with the Company's segments for the years ended December 31, 2021 and 2020. (in thousands) GCR ODR Total Goodwill as of January 1, 2020 $ — $ 6,129 $ 6,129 Goodwill as of December 31, 2020 — 6,129 6,129 Goodwill associated with the Jake Marshall Transaction — 5,241 5,241 Goodwill as of December 31, 2021 $ — $ 11,370 $ 11,370 Intangible Assets The Company reviews intangible assets with definite lives subject to amortization whenever events or changes in circumstances (triggering events) indicate that the carrying amount of an asset may not be recoverable. Intangible assets with definite lives subject to amortization are amortized on a straight-line or accelerated basis with estimated useful lives ranging from 1 to 15 years. Events or circumstances that might require impairment testing include the identification of other impaired assets within a reporting unit, loss of key personnel, the disposition of a significant portion of a reporting unit, a significant decline in stock price, or a significant adverse change in the Company’s business climate or regulations affecting the Company. During the third quarter of 2021, the Company performed a quantitative impairment test on its indefinite-lived intangible assets due to the triggering events described in the goodwill impairment summary above. The fair value of the Company's trade name was estimated using an income approach, specifically known as the relief-from-royalty method. The relief-from-royalty method is based on the hypothetical royalty stream that would be received if we were to license the trade name and was based on expected revenue. As a result of the interim assessment, the Company determined that the fair value of the Company's indefinite-lived intangible asset was greater than its respective carrying value. The impairment assessment concluded headroom of $1.0 million, or 10%, for the Company's trade name. The Company did not recognize an impairment charge on its indefinite-lived intangible asset for the years ended December 31, 2021 and 2020. Definite-lived and indefinite-lived intangible assets consist of the following: (in thousands) Gross Accumulated Net intangible December 31, 2021 Amortized intangible assets: Customer relationships – GCR – Jake Marshall $ 570 $ (6) $ 564 Customer relationships – ODR – Jake Marshall 3,050 (35) 3,015 Customer relationships – ODR – Limbach 4,710 (3,475) 1,235 Favorable leasehold interests (1) – Limbach 190 (82) 108 Backlog – GCR – Jake Marshall 260 (14) 246 Backlog – ODR – Jake Marshall 680 (36) 644 Trade name – Jake Marshall 1,150 (15) 1,135 Total amortized intangible assets 10,610 (3,663) 6,947 Unamortized intangible assets: Trade name – Limbach (2) 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 20,570 $ (3,663) $ 16,907 (1) During the first quarter of 2021, the Company reduced the gross carrying amount and accumulated amortization associated with its favorable leasehold interests intangible asset by $0.3 million due to the lease termination of its Western Pennsylvania office associated with the intangible asset. (2) The Company has determined that its trade name has an indefinite useful life. The Limbach trade name has been in existence since the Company’s founding in 1901 and therefore is an established brand within the industry. (in thousands) Gross Accumulated Net intangible December 31, 2020 (1) Amortized intangible assets: Customer relationships – ODR – Limbach $ 4,710 $ (3,112) $ 1,598 Favorable leasehold interests – Limbach 530 (407) 123 Total amortized intangible assets 5,240 (3,519) 1,721 Unamortized intangible assets: Trade name – Limbach 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 15,200 $ (3,519) $ 11,681 (1) The Backlog - GCR - Limbach intangible asset previously shown at December 31, 2020 has been fully amortized. Accordingly, its gross carrying amount of $4.8 million and corresponding accumulated amortization of $4.8 million have been removed from the table. Total amortization expense for these amortizable intangible assets was $0.5 million and $0.6 million for the years ended December 31, 2021 and 2020, respectively. The estimated remaining useful lives of definite-lived intangible assets are as follows: Intangible Asset Amortization Method Estimated Remaining Useful Customer relationships – GCR – Jake Marshall Straight line 7.0 Customer Relationships – ODR – Limbach Pattern of economic benefit 9.0 Customer Relationships – ODR – Jake Marshall Straight line 7.5 Favorable Leasehold Interests – Limbach Straight line 7.2 Backlog – GCR – Jake Marshall Straight line 1.5 Backlog – ODR – Jake Marshall Straight line 1.5 Trade name – Jake Marshall Straight line 6.1 Estimated amortization expense is as follows for the years ending December 31: (in thousands) Estimated Amortization Expense 2022 $ 1,567 2023 1,211 2024 867 2025 830 2026 800 2027 and thereafter 1,672 Total $ 6,947

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities are comprised of the following: ( in thousand s) December 31, 2021 December 31, 2020 Accrued payroll and related liabilities $ 8,169 $ 7,975 Accrued bonus and commissions 7,352 7,652 Accrued insurance liabilities 719 1,008 Accrued job costs 3,772 3,131 Assurance-type warranty liabilities 3,310 4,056 Other accrued liabilities 1,122 925 Total $ 24,444 $ 24,747 The Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) includes several taxpayer favorable provisions, one of which is the allowance for the deferral of the employer contribution of Federal Insurance Contributions Act (“FICA”) taxes. As of December 31, 2021, the company had a $3.2 million liability for FICA withholding, recorded as an accrued payroll liability, with the remaining balance recorded in accrued expenses and other current liabilities. Our construction-type contracts regularly include warranties to end customers that guarantee the work performed against defects in workmanship and the material we supply. These standard warranties are assurance-type warranties and do not offer any additional services. Therefore, these assurance-type warranties are not considered separate performance obligations and the expected cost of assurance-type warranties are accrued as an expense within cost of sales. Our reconciliation of assurance-type warranties are as follows: ( in thousand s) December 31, 2021 December 31, 2020 Balance at the beginning of the period $ 4,056 $ 2,886 Accruals for warranties issued 432 687 Accruals related to pre-existing warranties (including changes in estimates) 401 1,856 Settlements made (1,579) (1,373) Balance at the end of the period $ 3,310 $ 4,056

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt	Debt Long-term debt consists of the following obligations: ( in thousand s) December 31, 2021 December 31, 2020 A&R Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in December 2021) plus interest through February 2026 $ 34,881 $ — A&R Wintrust Revolving Loan — — 2019 Refinancing Term Loan – term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022 — 39,000 Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.55% to 6.45% through 2026 5,132 6,459 Total debt $ 40,013 $ 45,459 Less - Current portion of long-term debt (9,879) (6,536) Less - Unamortized discount and debt issuance costs (318) (2,410) Long-term debt $ 29,816 $ 36,513 Maturities of long-term debt and finance leases at December 31, 2021 are as follows: ( in thousands ) 2022 $ 9,879 2023 8,997 2024 8,247 2025 7,710 2026 5,180 Total $ 40,013 2019 Refinancing Agreement - 2019 Term Loans On April 12, 2019 (the “2019 Refinancing Closing Date”), LFS entered into a financing agreement (the “2019 Refinancing Agreement”) with the lenders thereto and Cortland Capital Market Services LLC, as collateral agent and administrative agent and CB Agent Services LLC (“CB”), as origination agent. The 2019 Refinancing Agreement consisted of (i) a $40.0 million term loan (the “2019 Refinancing Term Loan”) and (ii) a new $25.0 million multi-draw delayed draw term loan (the “2019 Delayed Draw Term Loan” and, collectively with the 2019 Refinancing Term Loan, the “2019 Term Loans”). Proceeds from the 2019 Refinancing Term Loan were used to repay the then existing credit agreement, to pay related fees and expenses thereof and to fund working capital of the 2019 Refinancing Borrowers (defined below). Proceeds of the 2019 Delayed Draw Term Loan were to be used to fund permitted acquisitions under the 2019 Refinancing Agreement and related fees and expenses in connection therewith. LFS and each of its subsidiaries were borrowers (the “2019 Refinancing Borrowers”) under the 2019 Refinancing Agreement. In addition, the 2019 Refinancing Agreement was guaranteed by the Company and LHLLC (each, a “2019 Refinancing Guarantor”, and together with the Borrowers, the “Loan Parties”). The 2019 Refinancing Agreement was secured by a first-priority lien on the real property of the Loan Parties and a second-priority lien on substantially all other assets of the Loan Parties, behind the 2019 ABL Credit Agreement (defined below). The respective lien priorities of the 2019 Refinancing Agreement and the 2019 ABL Credit Agreement were governed by an intercreditor agreement. The interest rate on borrowings under the 2019 Refinancing Agreement was, at the 2019 Refinancing Borrowers’ option, either LIBOR (with a 2.00% floor) plus 11.00% or a base rate (with a 3.00% minimum) plus 10.00%. At February 24, 2021 (the “2021 Refinancing Date”) and December 31, 2020. The interest rate in effect on the 2019 Refinancing Term Loan was 13.00%. Prior to its refinancing in February 2021, the 2019 Refinancing Agreement would have matured on April 12, 2022. Required amortization was $1.0 million per quarter and commenced with the fiscal quarter ending September 30, 2020. There was an unused line fee of 2.0% per annum on the undrawn portion of the 2019 Delayed Draw Term Loan, and there was a make-whole premium on prepayments made prior to the 19-month anniversary of the 2019 Refinancing Closing Date. This make-whole provision guaranteed that the Company would pay no less than 18 months’ applicable interest to the lenders under the 2019 Refinancing Agreement. The 2019 Refinancing Agreement contained representations and warranties, and covenants which were customary for debt facilities of this type. Unless the Required Lenders (as defined in the 2019 Refinancing Agreement) otherwise consented in writing, the covenants limited the ability of the Company and its restricted subsidiaries to, among other things, (i) incur additional indebtedness or issue preferred stock, (ii) pay dividends or make distributions to the Company’s stockholders, (iii) purchase or redeem the Company’s equity interests, (iv) make investments, (v) create liens on their assets, (vi) enter into transactions with the Company’s affiliates, (vii) sell assets and (viii) merge or consolidate with, or dispose of substantially all of the Company’s assets to, other companies. In addition, the 2019 Refinancing Agreement included customary events of default and other provisions that could have required all amounts due thereunder to become immediately due and payable, either automatically or at the option of the lenders, if the Company failed to comply with the terms of the 2019 Refinancing Agreement or if other customary events occurred. Furthermore, the 2019 Refinancing Agreement also contained two financial maintenance covenants for the 2019 Refinancing Term Loan, including a requirement to have sufficient collateral coverage of the aggregate outstanding principal amount of the 2019 Term Loans and as of the last day of each month for the total leverage ratio of the Company and its subsidiaries (the “Total Leverage Ratio”) not to exceed an amount beginning at 4.25 to 1.00 through June 30, 2019, and stepping down to 2.00 to 1.00 effective July 1, 2021. From July 1, 2019 through September 30, 2019, the Total Leverage Ratio may not exceed 4.00 to 1.00. As of August 31, 2019, the Company’s Total Leverage Ratio for the preceding twelve consecutive fiscal month period was 4.61 to 1.00, which did not meet the 4.00 to 1.00 requirement. The lender has waived the event of default arising from this noncompliance as of August 31, 2019, while reserving its rights with respect to covenant compliance in future months. In addition, the parties to the 2019 Refinancing Agreement entered into an amendment which, among other changes, revised the maximum permitted Total Leverage Ratio, starting at 3.30 to 1.00 on October 1, 2019 with a peak ratio of 4.25 during March 2020 along with varying monthly rates culminating in the lowest Total Leverage Ratio of 2.00 to 1.00 on April 1, 2021, through the term of such agreement. The 2019 Refinancing Agreement contained a post-closing covenant requiring the remediation of the Company’s material weakness that management determined in 2018 was in existence no later than December 31, 2020 and to provide updates as to the progress of such remediation, provided that, if such remediation was not completed on or prior to December 31, 2019, (x) the Company would be required to pay the post-closing fee pursuant to the terms of the Origination Agent Fee Letter (as defined in the 2019 Refinancing Agreement) and (y) the applicable margin would be increased by 1.00% per annum for the period from January 1, 2020 until the date at which the material weakness was no longer disclosed or required to be disclosed in the Company’s SEC filings or audited financial statements of the Company or related auditor’s reports. In connection with the 2019 Refinancing Amendment Number One and Waiver, dated November 14, 2019, the parties amended certain provisions of the 2019 Refinancing Agreement, including, among other changes to: (i) require, commencing October 1, 2019, a 3.00% increase in the interest rate on borrowings under the 2019 Refinancing Agreement; (ii) require the approval of CB and, generally, the lenders representing at least 50.1% of the aggregate undrawn term loan commitment or unpaid principal amount of the 2019 Term Loans, prior to effecting any permitted acquisition; (iii) revise the maximum permitted Total Leverage Ratio, starting at 3.30 to 1.00 on October 1, 2019 with a peak ratio of 4.25 during March 2020 along with varying monthly rates culminating in the lowest Total Leverage Ratio of 2.00 to 1.00 on April 1, 2021 and thereafter through the term of the 2019 Refinancing Agreement; and (iv) require the liquidity of the loan parties, which is generally calculated by adding (a) unrestricted cash on hand of the Loan Parties maintained in deposit accounts subject to control agreements granting control to the collateral agent for the 2019 ABL Credit Agreement, to (b) the difference between (1) the lesser of (x) $15 million, as adjusted from time to time, and (y) 75% of certain customer accounts resulting from the sale of goods or services in the ordinary course of business minus certain reserves established by the Administrative Agent and (2) the sum of (x) the outstanding principal balance of all revolving loans under the 2019 ABL Credit Agreement plus (y) the aggregate undrawn available amount of all letters of credit then outstanding plus the amount of any obligations that arise from any draw against any letter of credit that have not been reimbursed by the borrowers or funded with a revolving loan under the 2019 ABL Credit Agreement (the “Loan Parties Liquidity”), as of the last day of any fiscal month ending on or after November 30, 2019, of at least $10,000,000. As a condition to executing the 2019 Refinancing Amendment Number One and Waiver, the loan parties were required to pay a non-refundable waiver fee of $400,000 and a non-refundable amendment fee of $1,000,000 (the “PIK First Amendment Fee”, which were paid in kind by adding the PIK First Amendment Fee to the outstanding principal amount of the 2019 Refinancing Term Loan as additional principal obligations thereunder on and as of the effective date of the 2019 Refinancing Amendment Number One and Waiver). During December 2020, the Company was not in compliance with the collateral coverage debt covenant as defined by the 2019 Refinancing Agreement. The Company was required to maintain at all times a Collateral Coverage Amount (as defined in the 2019 Refinancing Agreement) equal to or greater than the aggregate outstanding principal amount of the 2019 Term Loans. The Company calculated its Collateral Coverage amount at $37.9 million as of December 31, 2020, the aggregate outstanding principal amount of Term Loans was $39.0 million as of that same date for an excess of debt over collateral of $1.1 million. On February 1, 2021, the Company, LFS and LHLLC entered into a Waiver - Collateral Coverage Amount (December 2020) (the “December 2020 Waiver”) with the lenders party thereto and Cortland Capital Market Services LLC, as collateral agent and administrative agent. The December 2020 Waiver included a waiver of the Company's compliance with the Collateral Coverage Amount for the month ended December 31, 2020. The lender waived the event of default arising from this noncompliance as of December 31, 2020, while reserving its rights with respect to covenant compliance in future months. On February 24, 2021 (the “2021 Refinancing Date”), the Company refinanced its 2019 Refinancing Term Loan and 2019 Revolving Credit Facility with proceeds from the issuance of the Wintrust Term Loan (defined below) (the “2021 Refinancing”). As a result of the 2021 Refinancing, the Company prepaid all principal, interest, fees and other obligations outstanding under the 2019 Refinancing Agreements and terminated its 2019 Refinancing Term Loan and 2019 Refinancing Revolving Credit Facility. In addition, on the 2021 Refinancing Date, the Company recognized a loss on the early extinguishment of debt of $2.0 million, which consisted of the write-off of $2.6 million of unamortized discount and financing costs, the reversal of the $2.0 million CB warrants (defined below) liability and the prepayment penalty and other extinguishment costs of $1.4 million. 2019 Refinancing Agreement – CB Warrants In connection with the 2019 Refinancing Agreement, on the 2019 Refinancing Closing Date, the Company issued to CB and the other lenders under the 2019 Refinancing Agreement warrants (the “CB Warrants”) to purchase up to a maximum of 263,314 shares of the Company's common stock at an exercise price of $7.63 per share subject to certain adjustments, including for stock dividends, stock splits or reclassifications. The actual number of shares of common stock into which the CB Warrants were exercisable at any given time were equal to: (i) the product of (x) the number of shares equal to 2% of the Company’s issued and outstanding shares of common stock on the 2019 Refinancing Closing Date on a fully diluted basis and (y) the percentage of the total 2019 Delayed Draw Term Loan made as of the exercise date, minus (ii) the number of shares previously issued under the CB Warrants. As of the 2019 Refinancing Closing Date through February 24, 2021, no amounts had been drawn on the 2019 Delayed Draw Term Loan, so no portion of the CB Warrants were exercisable. The CB Warrants were to be exercised for cash or on a “cashless basis,” subject to certain adjustments, at any time after the 2019 Refinancing Closing Date until the expiration of such warrant at 5:00 p.m., New York time, on the earlier of (i) the five (5) year anniversary of the 2019 Refinancing Closing Date, or (ii) the liquidation of the Company. The CB Warrants represented a freestanding financial instrument that was classified as a liability because the CB Warrants met the definition of a derivative instrument that did not meet the equity scope exception (i.e., the CB Warrants were not indexed to the entity’s own equity). In addition, the material weakness penalty described above was evaluated as an embedded derivative liability and bifurcated from the 2019 Term Loans as it represented a non-credit related embedded feature that provided for net settlement. Both the CB Warrants liability and the embedded derivative liability were required to be initially and subsequently measured at fair value. The initial fair values of the CB Warrants liability and the embedded derivative liability approximated $0.9 million and $0.4 million, respectively, on the 2019 Refinancing Closing Date. As the Company remediated the material weakness associated with the embedded derivative as of December 31, 2019, the $0.4 million embedded derivative was fully reversed at that date and is included in the consolidated statements of operations as a gain on embedded derivative. The CB Warrants liability was included in other long-term liabilities. The Company estimated these fair values by using the Black-Scholes-Merton option pricing model and a probability-weighted discounted cash flow approach. The proceeds for the 2019 Refinancing Term Loan were first allocated to the CB Warrants liability and embedded derivative liability based on their respective fair values with a corresponding amount of $1.3 million recorded as a debt discount to the 2019 Term Loans. In addition, the Company incurred approximately $3.9 million of debt issuance costs, including $1.4 million related to the first amendment, for the 2019 Term Loans that have also been recorded as a debt discount. The combined debt discount from the CB Warrants liability, embedded derivative liability and the debt issuance costs were being amortized into interest expense over the term of the 2019 Term Loans using the effective interest method and were expensed on the Refinancing Date as a loss on early debt extinguishment. The Company recorded interest expense for the amortization of the CB Warrants liability and embedded derivative debt discounts of $0.1 million for the period from January 1, 2021 through the 2021 Refinancing Date and $0.5 million for the year ended December 31, 2020. In addition to the amortization of the debt discounts into interest expense, the Company recorded $0.1 million of interest expense for the amortization of debt issuance costs related to the 2019 Refinancing Term Loan for the period from January 1, 2021 through the 2021 Refinancing Date and $1.4 million for the year ended December 31, 2020. 2019 ABL Credit Agreement On the 2019 Refinancing Closing Date, LFS also entered into a financing agreement with the lenders thereto and Citizens Bank, N.A., as collateral agent, administrative agent and origination agent (the “2019 ABL Credit Agreement” and, together with the 2019 Refinancing Agreement, the “Refinancing Agreements”). The 2019 ABL Credit Agreement consisted of a $15.0 million revolving credit facility (the “2019 Revolving Credit Facility”). Proceeds of the 2019 Revolving Credit Facility were to be used for general corporate purposes. On the 2019 Refinancing Closing Date, the Company had nothing drawn on the ABL Credit Agreement and $14.0 million of available borrowing capacity thereunder (net of a $1.0 million reserve imposed by the lender). The 2019 Refinancing Borrowers and 2019 Refinancing Guarantors under the 2019 ABL Credit Agreement were the same as under the 2019 Refinancing Agreement. The 2019 ABL Credit Agreement was secured by a second-priority lien on the real property of the Loan Parties (behind the 2019 Refinancing Agreement) and a first-priority lien on substantially all other assets of the Loan Parties. The interest rate on borrowings under the 2019 ABL Credit Agreement was, at the 2019 Refinancing Borrowers’ option, either LIBOR (with a 2.0% floor) plus an applicable margin ranging from 3.00% to 3.50% or a base rate (with a 3.0% minimum) plus an applicable margin ranging from 2.00% to 2.50%. At February 24, 2021 and December 31, 2020, the interest rate in effect on the 2019 ABL Credit Agreement was 5.25%. The 2019 ABL Credit Agreement was set to mature on April 12, 2022. There was also an unused line fee ranging from 0.250% to 0.375% per annum on undrawn amounts. The 2019 ABL Credit Agreement contained representations and warranties, and covenants which were customary for debt facilities of this type. Unless the Required Lenders otherwise consented in writing, the covenants limited the ability of the Company and its restricted subsidiaries to, among other things, generally, to (i) incur additional indebtedness or issue preferred stock, (ii) pay dividends or make distributions to the Company’s stockholders, (iii) purchase or redeem the Company’s equity interests, (iv) make investments, (v) create liens on their assets, (vi) enter into transactions with the Company’s affiliates, (vii) sell assets other than in the ordinary course of business or another permitted disposition of assets and (viii) merge or consolidate with, or dispose of substantially all of the Company’s assets to, other companies. The 2019 ABL Credit Agreement included customary events of default and other provisions that could have required all amounts due thereunder to become immediately due and payable, either automatically or at the option of the lenders, if the Company failed to comply with the terms of the 2019 ABL Credit Agreement or if other customary events occurred. The 2019 ABL Credit Agreement also contained a financial maintenance covenant for the 2019 Revolving Credit Facility, which was a requirement for the Total Leverage Ratio of the Company and its subsidiaries not to exceed an amount beginning at 4.00 to 1.00 through September 30, 2019, and stepping down to 1.75 to 1.00 effective July 1, 2021. In November 2019, the parties to the 2019 ABL Credit Agreement entered into an amendment which, among other changes revised the maximum permitted Total Leverage Ratio, starting at 3.30 to 1.00 on October 1, 2019 with a peak ratio of 4.25 during March 2020 along with varying monthly rates culminating in the lowest Total Leverage Ratio of 2.00 to 1.00 on April 1, 2021 through the term of such agreement. In connection with the 2019 ABL Credit Amendment Number One and Waiver, the parties amended certain provisions of the 2019 ABL Credit Agreement, including, among other changes to (i) require the approval of the origination agent and, generally, the lenders representing at least 50.1% of the aggregate undrawn revolving loan commitment or unpaid principal amount of the 2019 Term Loans, prior to effecting any permitted acquisition; (ii) revise the maximum permitted Total Leverage Ratio, starting at 3.30 to 1.00 on October 1, 2019 with a peak ratio of 4.25 during March 2020 along with varying monthly rates culminating in the lowest Total Leverage Ratio of 2.00 to 1.00 on April 1, 2021 through the term of the 2019 ABL Credit Agreement; and (iii) require the Loan Parties Liquidity as of the last day of any fiscal month ending on or after November 30, 2019, of at least $10,000,000, as described above in the Amendment Number One to 2019 Refinancing Agreement and Waiver. As a condition to executing the 2019 ABL Credit Amendment Number One and Waiver, the loan parties were required to pay a non-refundable waiver fee of $7,500. As noted above, the Company was subject to cross-default under our 2019 Revolving Credit Facility as a result of our failure to satisfy the Collateral Coverage Amount as defined in the 2019 Refinancing Agreement, which required the company to obtain a waiver. Accordingly, on February 1, 2021, the Company, LFS and LHLLC entered into a Waiver - Collateral Coverage Amount (December 2020) (“December 2020 Waiver”) with the lenders party thereto and Citizens Bank, N.A., as collateral agent and administrative agent. The December 2020 Waiver included a waiver of the Company's compliance with the Collateral Coverage Amount for the month ending December 31, 2020. At the time, the lender waived the event of default arising from this noncompliance as of December 31, 2020, while reserving its rights with respect to covenant compliance in future months. At the 2021 Refinancing Date and December 31, 2020, the Company had irrevocable letters of credit each in the amount of $3.4 million with its lender to secure obligations under its self-insurance program. The Company incurred approximately $0.9 million of debt issuance costs for the 2019 ABL Credit Agreement that had been recorded as a non-current deferred asset. The deferred asset was amortized into interest expense over the term of the 2019 Term ABL Credit Agreement using the effective interest method and then expensed on the 2021 Refinancing Date as a loss on early debt extinguishment. The Company recorded interest expense of $0.1 million for the period from January 1, 2021 through the 2021 Refinancing Date and $0.3 million for the year ended December 31, 2020. Wintrust Term and Revolving Loans On the 2021 Refinancing Date, LFS, LHLLC and the direct and indirect subsidiaries of LFS from time to time included as parties to the agreement (the “Wintrust Guarantors”) entered into a credit agreement (the “Wintrust Credit Agreement”) by and among the LFS, LHLLC, Wintrust Guarantors, the lenders party thereto from time to time, Wheaton Bank & Trust Company, N.A., a subsidiary of Wintrust Financial Corporation (collectively, “Wintrust”), as administrative agent and L/C issuer, Bank of the West as documentation agent, M&T Bank as syndication agent, and Wintrust as lead arranger and sole book runner. In accordance with the terms of the Wintrust Credit Agreement, Lenders provided to LFS (i) a $30.0 million senior secured term loan (the “Wintrust Term Loan”); and (ii) a $25.0 million senior secured revolving credit facility with a $5.0 million sublimit for the issuance of letters of credit (the “Wintrust Revolving Loan” and, together with the Wintrust Term Loan, the “Wintrust Loans”). Proceeds of the Wintrust Loans were used to refinance certain existing indebtedness, finance working capital and other general corporate purposes and fund certain fees and expenses associated with the closing of the Wintrust Loans. The Wintrust Revolving Loan bore interest, at LFS’s option, at either LIBOR (with a 0.25% floor) plus 3.5% or a base rate (with a 3.0% floor) plus 0.50%, subject to a 50 basis point step-down based on the ratio between the senior debt of the Company and its subsidiaries to the EBITDA (earnings before interest, income taxes, depreciation and amortization) of the LFS and its subsidiaries for the most recently ended four fiscal quarters. The Wintrust Term Loan bore interest, at LFS’s option, at either LIBOR (with a 0.25% floor) plus 4.0% or a base rate (with a 3.0% floor) plus 1.00%, subject to a 50 (for LIBOR) or 75 (for base rate) basis point step-down based on the Senior Leverage Ratio. LFS was required to make principal payments on the Wintrust Term Loan in $0.5 million installments on the last business day of each month commencing on March 31, 2021 with a final payment of all principal and interest not sooner paid on the Wintrust Term Loan due and payable on February 24, 2026. In conjunction with the Jake Marshall Transaction, the Company entered into an amendment to the Wintrust Credit Agreement (the “A&R Wintrust Credit Agreement”). In accordance with the terms of the A&R Credit Agreement, Lenders provided to LFS (i) a $35.5 million senior secured term loan (the “A&R Wintrust Term Loan”); and (ii) a $25 million senior secured revolving credit facility with a $5 million sublimit for the issuance of letters of credit (the “A&R Wintrust Revolving Loan” and, together with the Term Loan, the “A&R Wintrust Loans”). The overall Wintrust Term Loan commitment under the A&R Wintrust Credit Agreement was recast at $35.5 million in connection with the A&R Credit Agreement. A portion of the A&R Wintrust Term Loan commitment was used to fund the closing purchase price of the Jake Marshall Transaction. The A&R Credit Agreement was also amended to: (i) permit the Company to undertake the Jake Marshall Transaction (ii) make certain adjustments to the covenants under the A&R Credit Agreement (which were largely done to make certain adjustments for the Jake Marshall Transaction) (iii) allow for the Earnout Payments under the Jake Marshall Transaction and (iv) make other corresponding changes to the A&R Credit Agreement. The A&R Wintrust Revolving Loan bears interest, at LFS’s option, at either Term SOFR (as defined in the A&R Credit Agreement) (with a 0.15% floor) plus 3.60%, 3.76% or 3.92% for a tenor of one month, three months or six months, respectively, or a base rate (as set forth in the A&R Credit Agreement) (with a 3.0% floor) plus 0.50%, subject to a 50 basis point step-down based on the ratio between the senior debt of the Company and its subsidiaries to the EBITDA of LFS and its subsidiaries for the most recently ended four fiscal quarters (the “Senior Leverage Ratio”). The A&R Wintrust Term Loan bears interest, at LFS’s option, at either Term SOFR (with a 0.15% floor) plus 4.10%, 4.26% or 4.42% for a tenor of one month, three months or six months, respectively, or a base rate (with a 3.0% floor) plus 1.00%, subject to a 50 (for Term SOFR) or 75 (for base rate) basis point step-down based on the Senior Leverage Ratio. LFS is required to make principal payments on the A&R Wintrust Term Loan in installments of approximately $0.6 million on the last business day of each month commencing on December 31, 2021. Subject to defaults and remedies under the A&R Credit Agreement, the final payment of all principal and interest not sooner paid on the A&R Wintrust Term Loan is due and payable on February 24, 2026. Subject to defaults and remedies under the A&R Credit Agreement, the A&R Wintrust Revolving Loan matures and becomes due and payable by LFS on February 24, 2026. The A&R Wintrust Loans are secured by (i) a valid, perfected and enforceable lien of the administrative agent on the ownership interests held by each of LFS and Wintrust Guarantors in their respective subsidiaries; and (ii) a valid, perfected and enforceable lien of the administrative agent on each of LFS and Wintrust Guarantors’ personal property, fixtures and real estate, subject to certain exceptions and limitations. Additionally, the re-payment of the A&R Wintrust Loans shall be jointly and severally guaranteed by each Wintrust Guarantor. The A&R Credit Agreement contains representations and warranties, covenants and events of default that are customary for facilities of this type, as more particularly described in the A&R Credit Agreement. The A&R Wintrust Loans also contain three financial maintenance covenants, including (i) a requirement to have as of the last day of each quarter for the senior leverage ratio of the Company and its subsidiaries not to exceed an amount beginning at 2.00 to 1.00 (ii) a fixed charge coverage ratio of not less than 1.20 to 1.00 as of the last day of each fiscal quarter commencing with the fiscal quarter ending December 31, 2021, and (iii) no unfinanced capital expenditures, except for unfinanced capital expenditures in the ordinary course of business not exceeding in the aggregate $4.0 million during any fiscal year; and no default or event of default (as defined by the agreement) has occurred and is continuing, 50% of any portion of this annual limit, if not expended in the fiscal year for which it is permitted, may be carried over for expenditure in the next following fiscal year as stipulated by the agreement. LFS and its affiliates maintain various commercial and service relationships with certain members of the syndicate and their affiliates in the ordinary course of business. As of December 31, 2021, the Company was in compliance with all financial maintenance covenants as required by the A&R Wintrust Loans. The following is a summary of the applicable margin and commitment fees payable on the available A&R Wintrust Term Loan and A&R Wintrust Revolving Loan credit commitment: Level Senior Leverage Ratio Applicable Margin for Applicable Margin for Applicable Margin for Commitment Fee I Greater than 1.00 to 1.00 1.00 % 0.50 % 0.25 % II Less than or equal to 1.00 to 1.00 0.25 % — % 0.25 % At December 31, 2021, the interest rate in effect on the Wintrust Term Loan was 4.25% and the interest rate in effect on the Wintrust Revolving Loan was 3.75%.

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings per Share	Earning per Share Earnings per Share The Company calculates earnings per share in accordance with ASC Topic 260 - Earnings Per Share (“EPS”) . Basic earnings per common share applicable to common stockholders is computed by dividing earnings applicable to common stockholders by the weighted-average number of common shares outstanding and assumed to be outstanding. Diluted EPS assumes the dilutive effect of outstanding common stock warrants, shares issued in conjunction with the Company’s ESPP (defined in Note 9) and restricted stock units (“RSUs”), all using the treasury stock method. The following table sets forth the computation of the basic and diluted earnings per share attributable to the Company's common stockholders for the years ended December 31, 2021 and 2020: For the Years Ended (in thousands, except per share amounts) December 31, 2021 December 31, 2020 EPS numerator: Net income $ 6,714 $ 5,807 EPS denominator: Weighted average shares outstanding – basic 10,013 7,865 Nonvested restricted stock units 215 191 Employee stock purchase plan 4 9 Weighted average shares outstanding – diluted 10,232 8,065 EPS: Basic $ 0.67 $ 0.74 Diluted $ 0.66 $ 0.72 The following table summarizes the securities that were antidilutive or out-of-the-money, and therefore, were not included in the computations of diluted income per common share: For the Years Ended December 31, 2021 December 31, 2020 Out-of-the-money warrants (1) 2,981,473 4,576,799 Service-based RSUs 54 7,471 Performance and market-based RSUs (2) 14,164 276 Employee stock purchase plan — 3,217 Total 2,995,691 4,587,763 (1) On July 20, 2021, 2,140,214 Public Warrants, 99,000 Private Warrants, and 935,068 Additional Merger Warrants expired by their terms. Through their date of expiration, the Company calculated, on a security-by-security basis, the average market price for the portion of the period in which these securities were outstanding and concluded that these warrants were considered out-of-the-money, and therefore, were not included in the computation of diluted income per common share. (2) For the years ended December 31, 2021 and 2020, certain PRSU and MRSU awards (each defined in Note 16) were not included in the computation of diluted income per common share because the performance and market conditions were not satisfied during the periods and would not be satisfied if the reporting date was at the end of the contingency period.

Equity

Equity	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Equity	Equity The Company’s second amended and restated certificate of incorporation currently authorizes the issuance of 100,000,000 shares of common stock, par value $0.0001, and 1,000,000 shares of preferred stock, par value $0.0001. Warrants In conjunction with the Company's initial public offering, the Company issued Public Warrants, Private Warrants and $15 Exercise Price Sponsor Warrants (each defined below). The Merger Warrants and Additional Merger Warrants (each defined below) were issued in conjunction with the Company's business combination with LHLLC in July 2016 (the “Business Combination”). The following table summarizes the underlying shares of common stock with respect to outstanding warrants: December 31, 2021 December 31, 2020 Public Warrants (1)(6) — 2,300,000 Private Warrants (2)(6) — 99,000 $15 Exercise Price Warrants (3)(6) 600,000 600,000 Merger Warrants (4)(7) 629,643 631,119 Additional Merger Warrants (5)(7) — 946,680 Total 1,229,643 4,576,799 (1) Exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Public Warrants”). (2) Exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Private Warrants”). (3) Exercisable for one share of common stock at an exercise price of $15.00 per share (“$15 Exercise Price Sponsor Warrants”). (4) Exercisable for one share of common stock at an exercise price of $12.50 per share (“Merger Warrants”). (5) Exercisable for one share of common stock at an exercise price of $11.50 per share (“Additional Merger Warrants”). (6) Issued under a warrant agreement dated July 15, 2014, between Continental Stock Transfer and Trust Company, as warrant agent, and the Company. (7) Issued to the sellers of LHLLC. On July 20, 2021, the Public Warrants, Private Warrants, and Additional Merger Warrants expired by their terms. Incentive Plan Upon the consummation of the Business Combination, the Company adopted an omnibus incentive plan (the “Omnibus Incentive Plan”) for which all future equity awards will be granted thereunder. The Company reserved 800,000 shares of its common stock for issuance under the Omnibus Incentive Plan. On April 29, 2019, the Board of Directors approved further amendments to the Company's initial Omnibus Incentive Plan (the “2019 Amended and Restated Omnibus Incentive Plan”) to increase the number of shares of the Company's common stock that may be issued pursuant to awards by 350,000, for a total of 1,150,000 shares, and extended the term of the plan so that it will expire on the tenth anniversary of the date the stockholders approve the 2019 Amended and Restated Omnibus Incentive Plan. The amendments were approved by the Company's stockholders at the Annual Meeting held on May 30, 2019. On May 24, 2020, the Board of Directors approved further amendments to the Company's initial Omnibus Incentive Plan (the “2020 Amended and Restated Omnibus Incentive Plan”) to increase the number of shares of the Company's common stock that may be issued pursuant to awards by 500,000, for a total of 1,650,000 shares, and extended the term of the plan so that it will expire on the tenth anniversary of the date the stockholders approve the 2020 Amended and Restated Omnibus Incentive Plan. The amendments were approved by the Company's stockholders at the Annual Meeting held on July 14, 2020. On March 9, 2021, the Board of Directors approved amendments to the Company's 2020 Amended and Restated Omnibus Incentive Plan (the “2021 Amended and Restated Omnibus Incentive Plan”) to increase the number of shares of the Company's common stock that may be issued pursuant to awards by 600,000, for a total of 2,250,000 shares, and extended the term of the plan so that it will expire on the tenth anniversary of the date the stockholders approve the 2021 Amended and Restated Omnibus Incentive Plan. The amendments were approved by the Company's stockholders at the Annual Meeting held on June 16, 2021. See Note 16 for a discussion of the Company's management incentive plans for RSUs granted, vested, forfeited and remaining unvested. Employee Stock Purchase Plan Upon approval of the Company's stockholders on May 30, 2019, the Company adopted the Limbach Holdings, Inc. 2019 Employee Stock Purchase Plan (the “ESPP”). On January 1, 2020, the ESPP went into effect. The ESPP enables eligible employees, as defined by the ESPP, the right to purchase the Company’s common stock through payroll deductions during consecutive subscription periods at a purchase price of 85% of the fair market value of a common share at the end of each offering period. Annual purchases by participants are limited to the number of whole shares that can be purchased by an amount equal to ten percent of the participant's compensation or $5,000, whichever is less. Each offering period of the ESPP lasts six months, commencing on January 1st and July 1st of each year. The amounts collected from participants during a subscription period are used on the exercise date to purchase full shares of common stock. Participants may withdraw from an offering before the exercise date and obtain a refund of amounts withheld through payroll deductions. Compensation cost, representing the 15% discount applied to the fair market value of common stock, is recognized on a straight-line basis over the six-month vesting period during which employees perform related services. Under the ESPP 500,000 shares are authorized to be issued. For the years ended December 31, 2021 and 2020, the Company issued 25,068 and 30,825 shares of its common stock, respectively, to participants in the ESPP who contributed to the plan during these periods. As of December 31, 2021, 444,107 shares remain available for future issuance under the ESPP. 2021 Public Offering On February 10, 2021 the Company entered into an underwriting agreement (“Underwriting Agreement”) with Lake Street Capital Markets, LLC (“Underwriter”) relating to an underwritten public offering (the “2021 Public Offering”). On February 12, 2021, the Company sold to the Underwriter 1,783,500 shares of its common stock. The Underwriting Agreement provided for purchase and sale of the Shares by the company to the Underwriter at a price of $11.28 per share. The price to the public in the 2021 Public Offering was $12.00 per share. In addition, under the terms of the Underwriting Agreement, the Company granted the Underwriter a 30-day option to purchase up to an additional 267,525 shares of common stock to cover over-allotments, if any, on the same terms and conditions. The net proceeds to the Company from the 2021 Public Offering after deducting the underwriting discounts and commissions were approximately $19.8 million. On February 18, 2021, the Company received approximately $3.0 million of net proceeds for the sale of 267,525 shares of common stock in connection with the exercise of the over-allotment option.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is taxed as a C Corporation. On March 27, 2020, the CARES Act was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, allows NOLs incurred in 2018, 2019 and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. This allowed the Company to carryback net operating losses generated in 2018 and 2019 to prior tax years and generate a tax refund. The total refund generated by this carryback for the year ended December 31, 2020 was $1.6 million, of which all has been received. The income tax provision from income taxes for December 31, 2021 and 2020 consisted of the following: For the Years Ended (in thousands) December 31, 2021 December 31, 2020 Current tax provision U.S. Federal $ 812 $ 1,274 State and local 194 1,209 Total current tax provision 1,006 2,483 Deferred tax provision (benefit) U.S. Federal 1,127 (643) State and local 630 (658) Total deferred tax provision (benefit) 1,757 (1,301) Income tax provision $ 2,763 $ 1,182 In assessing the realizability of deferred tax assets, management considered whether it is more likely than not that some portion or all deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. In assessing the need for a valuation allowance, the Company considered both positive and negative evidence related to the likelihood of realization of the deferred tax assets. After giving consideration to these factors, management concluded that it was more likely than not that the deferred tax assets would be fully realized, and as a result, no valuation allowance against the deferred tax assets was deemed necessary at December 31, 2021 and 2020. The components of deferred tax assets (liabilities) were as follows: As of As of December 31, (in thousands) 2021 2020 Deferred tax assets: Accrued expenses $ 1,328 $ 2,096 Allowance for doubtful accounts 68 71 Intangibles 524 784 Goodwill 3,304 3,746 Startup costs 79 91 Stock-based compensation 881 501 Lease liabilities 5,547 5,268 Accrued bonuses and commissions 1,810 2,030 Warrant — 535 Total deferred tax assets 13,541 15,122 Deferred tax liabilities: Fixed assets (3,775) (3,813) Right-of-use assets (5,231) (4,975) Debt discounts — (155) Percentage of completion (205) (92) Total deferred tax liabilities (9,211) (9,035) Net deferred tax asset $ 4,330 $ 6,087 At December 31, 2021 and 2020, the Company had no net operating loss carryforwards. A reconciliation of the federal statutory income tax rate to the Company’s effective tax rate is as follows: For the Years Ended December 31, 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % State income taxes, net of federal tax effect 7.0 % 6.3 % Change in uncertain tax benefits — % (0.6) % Stock based compensation – restricted stock (1.1) % 2.0 % Return to provision adjustment 1.2 % (0.7) % Permanent differences 1.9 % 1.1 % Tax credits (0.8) % (2.7) % CARES Act carryback — % (9.4) % Effective tax rate 29.2 % 17.0 % The Company is subject to taxation in various jurisdictions. The Company’s 2018 through 2020 tax returns are subject to examination by U. S. federal authorities. The Company’s tax returns are subject to examination by various state authorities for the years 2018 and forward. The Company had previously recorded a liability for unrecognized tax benefits (“UTBs”) related to tax positions taken on its various income tax returns in open tax periods. When recognized, a portion of the UTBs would favorably impact the effective tax rate that is reported in future periods. The Company filed to change an improper tax method of accounting in the fourth quarter of 2020 related to the UTBs that affords the Company IRS audit protection in past periods. Therefore, the total UTBs were reduced in the fourth quarter of 2020. The Company had no UTBs as of December 31, 2021 and 2020.

Operating Segments

Operating Segments	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Operating Segments	Operating Segments As discussed in Note 1, on January 1, 2021, the Company renamed its two operating segments to reflect the Company's two distinct approaches to its customer base and to better align with its owner direct strategy. The previously named Construction segment is now known as GCR and the previously named Service segment is now known as ODR. These segments are reflective of how the Company’s Chief Operating Decision Maker (“CODM”) reviews operating results for the purposes of allocating resources and assessing performance. The Company's CODM is comprised of its Chief Executive Officer, Chief Financial Officer and Chief Operating Officer. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. The CODM evaluates performance based on income from operations of the respective branches after the allocation of Corporate office operating expenses. In accordance with ASC Topic 280 – Segment Reporting , the Company has elected to aggregate all of the construction branches into one GCR reportable segment and all of the service branches into one ODR reportable segment. All transactions between segments are eliminated in consolidation. The Company’s corporate department provides general and administrative support services to its two operating segments. The CODM allocates costs between segments for selling, general and administrative expenses and depreciation expense. All of the Company’s identifiable assets are located in the United States, which is where the Company is domiciled. The Company does not have sales outside of the United States. For the year ended December 31, 2021, two GCR segment customers accounted for approximately 17% and 12% of consolidated total revenue. For the year ended December 31, 2020, the Company had one GCR segment customer that accounted for approximately 14% of consolidated total revenue. Segment information for the periods presented is as follows: For the Years Ended December 31, (in thousands) 2021 2020 Statement of Operations Data: Revenue: GCR $ 350,015 $ 440,979 ODR 140,336 127,230 Total revenue 490,351 568,209 Gross profit: GCR 45,409 45,115 ODR 40,501 36,271 Total gross profit 85,910 81,386 Selling, general and administrative: GCR 37,558 37,708 ODR 31,277 24,825 Corporate 2,601 1,068 Total selling, general and administrative 71,436 63,601 Amortization of intangibles 484 630 Operating income $ 13,990 $ 17,155 Less Unallocated amounts: Interest expense, net (2,568) (8,627) Loss on debt extinguishment (1,961) — Gain (loss) on change in fair value of warrant liability 14 (1,634) Gain on sale of property and equipment 2 95 Total unallocated amounts (4,513) (10,166) Total consolidated income before income taxes $ 9,477 $ 6,989 Other Data: Depreciation and amortization: GCR $ 4,085 $ 4,187 ODR 1,379 1,354 Corporate 484 630 Total other data $ 5,948 $ 6,171 The Company does not identify capital expenditures and total assets by segment in its internal financial reports due in part to the shared use of a centralized fleet of vehicles and specialized equipment. Interest expense is also not allocated to segments because of the Company’s corporate management of debt service, including interest.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal . The Company is continually engaged in administrative proceedings, arbitrations, and litigation with owners, general contractors, suppliers and other unrelated parties, all arising in the ordinary courses of business. The ultimate resolution of these contingencies could, individually or in the aggregate, be material to the consolidated financial statements. In the opinion of the Company’s management, the current belief is that the results of these actions will not have a material adverse effect on the financial position, results of operations, or cash flows of the Company. On November 13, 2019, claimant, Lanzo Trenchless Technologies, Inc. – North (“Lanzo”), filed a Demand for Arbitration in the state of Michigan against the Company's wholly-owned subsidiary, Limbach Company LLC. The demand sought damages in excess of $0.4 million based upon the allegation that Limbach breached a construction contract by improperly terminating Lanzo’s subcontract, and for withholding payment from Lanzo based upon deficient performance. The Company filed a counterclaim against Lanzo, seeking to recover damages for Lanzo’s deficient work. In October of 2021, Lanzo and the Company negotiated a confidential settlement pursuant to which Lanzo paid the Company to resolve all claims, resulting in the matter being concluded. On January 23, 2020, plaintiff, Bernards Bros. Inc. (“Bernards”), filed a complaint against the Company in Superior Court of the State of California for the County of Los Angeles. The complaint alleges that the Company’s Southern California operations refused to honor a proposal made to Bernards to act as a subcontractor on a construction project, and that, as a result of the wrongful failure to honor the proposal, Bernards suffered damages in excess of $3.0 million, including alleged increased costs for hiring a different subcontractor to perform the work. The Company is vigorously defending the suit. A non-binding mediation took place on August 19, 2021 that did not result in a settlement. Per the agreement of the Company and Bernards, in January 2022, the Court appointed a private referee to manage the case and adjudicate the dispute. A trial date before the private referee is pending scheduling. As of December 31, 2021, the Company believes that a loss is neither probable nor reasonably estimable for this matter, and, as such, has not recorded a loss contingency. On April 17, 2020, plaintiff, LA Excavating, Inc., filed a complaint against the Company’s wholly-owned subsidiary, Limbach Company LP, and several other parties, in Superior Court of the State of California, for the County of Los Angeles. The complaint seeks damages of approximately $1.0 million for alleged failure to pay contract balances and extra work ordered by Limbach Company LP, as well as seeks to enforce payment obligations under a payment bond. The Company disputes the allegations and intends to vigorously defend the suit, which is currently set for mediation on May 11, 2022 and trial beginning on February 7, 2023. As of December 31, 2021, the Company believes that a loss is neither probable nor reasonably estimable for this matter, and, as such, has not recorded a loss contingency. On January 26, 2022, claimant, Suffolk Construction Company, Inc. (“Suffolk”) filed a Demand for Arbitration in Massachusetts against Boston Medical Center Corporation (“BMC”) and numerous of Suffolk’s trade subcontractors, including, the Company’s wholly-owned subsidiary, Limbach Company LLC, seeking to recover monies BMC withheld from Suffolk and its subcontractors based on an audit of project billings. Suffolk has demanded the Company to defend and indemnify Suffolk against BMC’s audit findings that the Company overbilled the project just over $0.3 million and for the Company’s share of BMC’s audit costs, which share has not been, and cannot currently be, quantified. The Company disputes the findings of BMC’s audit and intends to vigorously defend the allegation that it overbilled the project. A final arbitration hearing has not been scheduled. Because this matter was just filed, the Company cannot determine at this time if a loss is probable or reasonably estimable, and, as such, has not recorded a loss contingency. Surety. The terms of its construction contracts frequently require that the Company obtains from surety companies, and provide to its customers, payment and performance bonds (“Surety Bonds”) as a condition to the award of such contracts. The Surety Bonds secure its payment and performance obligations under such contracts, and the Company has agreed to indemnify the surety companies for amounts, if any, paid by them in respect of Surety Bonds issued on its behalf. In addition, at the request of labor unions representing certain of the Company's employees, Surety Bonds are sometimes provided to secure obligations for wages and benefits payable to or for such employees. Public sector contracts require Surety Bonds more frequently than private sector contracts, and accordingly, the Company's bonding requirements typically increase as the amount of public sector work increases. As of December 31, 2021, the Company had approximately $159.2 million in surety bonds outstanding. The surety bonds are issued by surety companies in return for premiums, which vary depending on the size and type of bond. Collective Bargaining Agreements. Many of the Company’s craft labor employees are covered by collective bargaining agreements. The agreements require the Company to pay specified wages, provide certain benefits and contribute certain amounts to multi-employer pension plans. If the Company withdraws from any of the multi-employer pension plans or if the plans were to otherwise become underfunded, the Company could incur additional liabilities related to these plans. Although the Company has been informed that some of the multi-employer pension plans to which it contributes have been classified as “critical” status, the Company is not currently aware of any significant liabilities related to this issue. Self-insurance . The Company is substantially self-insured for workers’ compensation and general liability claims, in the view of the relatively high per-incident deductibles we absorb under our insurance arrangements for these risks. The Company purchases workers’ compensation and general liability insurance under policies with per-incident deductibles of $250,000 per occurrence and a $4.4 million maximum aggregate deductible loss limit per year. Losses incurred over primary policy limits are covered by umbrella and excess policies up to specified limits with multiple excess insurers. The Company accrues for the unfunded portion of costs for both reported claims and claims incurred but not reported. The liability for unfunded reported claims and future claims is reflected on the consolidated balance sheets as current and non-current liabilities. The liability is determined by determining a reserve for each reported claim on a case-by-case basis based on the nature of the claim and historical loss experience for similar claims plus an allowance for the cost of incurred but not reported claims. The current portion of the liability is included in accrued expenses and other current liabilities on the consolidated balance sheet. The non-current portion of the liability is included in other long-term liabilities on the consolidated balance sheet. The Company is self-insured related to medical and dental claims under policies with annual per-claimant and annual aggregate stop-loss limits. The Company accrues for the unfunded portion of costs for both reported claims and claims incurred but not reported. The liability for unfunded reported claims and future claims is reflected on the consolidated balance sheets as a current liability in accrued expenses and other current liabilities. The components of the self-insurance liability as of December 31, 2021 and 2020 are as follows: (in thousands) December 31, 2021 December 31, 2020 Current liability — workers' compensation and general liability $ 184 $ 197 Current liability — medical and dental 456 764 Non-current liability 451 890 Total liability $ 1,091 $ 1,851 Restricted cash $ 113 $ 113 The restricted cash balance represents an imprest cash balance set aside for the funding of workers' compensation and general liability insurance claims. This amount is replenished either when depleted or at the beginning of each month.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Leases The Company leases real estate, trucks and other equipment. The determination of whether an arrangement is, or contains, a lease is performed at the inception of the arrangement. Classification and initial measurement of the right-of-use asset and lease liability are determined at the lease commencement date. The Company elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets. Instead, the short-term leases are recognized in expense on a straight-line basis over the lease term. The Company's arrangements include certain non-lease components such as common area and other maintenance for leased real estate, as well as mileage, fuel and maintenance costs related to leased vehicles. For all leased asset classes, the Company has elected to not separate non-lease components from lease components and will account for each separate lease component and non-lease component associated with the lease as a single lease component. The Company does not guarantee any residual value in its lease agreements, and there are no material restrictions or covenants imposed by lease arrangements. Real estate leases typically include one or more options to extend the lease. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. For the Company’s leased vehicles, the Company uses the interest rate implicit in its leases with the lessor to discount lease payments at the lease commencement date. When the implicit rate is not readily available, as is the case with the Company’s real estate leases, the Company uses quoted borrowing rates on its secured debt. Related Party Lease Agreement. In conjunction with the closing of the Jake Marshall Transaction, the Company entered into an operating lease for certain land and facilities owned by a former member of JMLLC who became a full-time employee of the Company. The lease term is ten years and includes an option to extend the lease for two successive periods of two years each through November 2035. Base rent for the term of the lease is $37,500 per month for the first five years with payment commencing on January 1, 2022. The fixed rent payment is escalated to $45,000 per month for years 6 through 10 of the lease term. Fixed rent payments for the extension term shall be increased from $45,000 by the percentage increase, if any, in the consumer price index from the lease commencement date. In addition, under the agreement, the Company is required to pay its share of estimated property taxes and operating expenses, both of which are variable lease expenses. Southern California Sublease . In June, 2021, the Company entered into a sublease agreement with a third party for the entire ground floor of its leased space in Southern California, consisting of 71,787 square feet. Under the terms of the sublease agreement, the sublessee is obligated to pay the Company base rent of approximately $0.6 million per year, which is subject to a 3.0% annual rent increase, plus certain operating expenses and other costs. The initial lease term commenced in September 2021 and continues through April 30, 2027. As of December 31, 2021, the Company remains obligated under the original lease for such office space and, in the event the subtenant of such office space fails to satisfy its obligations under the sublease, the Company would be required to satisfy its obligations directly to the landlord under such original lease. For the year ended December 31, 2021, the Company recorded $0.4 million of income in selling, general and administrative expenses related to this sublease agreement. The following table summarizes the lease amounts included in the Company’s consolidated balance sheets as of December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Balance Sheets December 31, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 20,119 $ 18,751 Finance Property and equipment, net (b) 4,916 6,242 Total lease assets $ 25,035 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,366 $ 3,929 Finance Current portion of long-term debt 2,451 2,536 Noncurrent Operating Long-term operating lease liabilities 16,576 15,459 Finance Long-term debt 2,681 3,923 Total lease liabilities $ 26,074 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.9 million and $11.9 million at December 31, 2021 and 2020, respectively. (b) Finance lease assets are recorded net of accumulated amortization of $5.9 million and $5.3 million at December 31, 2021 and 2020, respectively. The following table summarizes the lease costs included in the Company’s consolidated statements of operations for the years ended December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Statements of Operations December 31, 2021 December 31, 2020 Operating lease cost Cost of revenue (a) $ 2,901 $ 3,527 Operating lease cost Selling, general and administrative (a) 2,223 1,483 Finance lease cost: Amortization Cost of revenue (b) 2,622 2,711 Interest Interest expense, net (b) 305 363 Total lease cost $ 8,051 $ 8,084 (a) Operating lease costs recorded in cost of sales includes $0.5 million and $0.7 million of variable lease costs for both the years ended December 31, 2021 and 2020, respectively. In addition, $0.4 million and $0.3 million of variable lease costs are included in selling, general and administrative expenses for the years ended December 31, 2021 and 2020, respectively. These variable costs consist of our proportionate share of operating expenses, real estate taxes, and utilities. (b) Finance lease costs recorded in cost of revenue includes $2.8 million and $2.4 million of variable leases costs for the years ended December 31, 2021 and 2020, respectively. These variable lease costs consist of fuel, maintenance, and sales tax charges. No variable lease costs for finance leases were recorded in selling, general and administrative expenses for the years ended December 31, 2021 or 2020. Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of the year ended December 31, 2021 were as follows (in thousands): Operating Leases Year ending December 31: Finance Non-Related Party Related Party (1) Sublease Receipts (2) Total Operating 2022 $ 2,658 $ 4,800 $ 450 $ (657) $ 4,593 2023 1,662 3,516 450 (677) 3,289 2024 851 2,917 450 (697) 2,670 2025 289 2,409 450 (718) 2,141 2026 12 2,010 450 (740) 1,720 Thereafter — 2,033 4,815 (250) 6,598 Total minimum lease payments $ 5,472 $ 17,685 $ 7,065 $ (3,739) $ 21,011 Amounts representing interest (340) Present value of net minimum lease payments $ 5,132 (1) Associated with the aforementioned related party lease entered into with a former member of JMLLC. (2) Associated with the aforementioned third party sublease. The following is a summary of the lease terms and discount rates as of: December 31, 2021 December 31, 2020 Weighted average lease term (in years) Operating 7.10 5.48 Finance 2.51 2.78 Weighted average discount rate Operating 4.68 % 4.83 % Finance 5.27 % 5.50 % The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Year Ended December 31, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 4,938 $ 5,164 Operating cash flows from finance leases 305 363 Financing cash flows from finance leases 2,623 2,664 Right-of-use assets exchanged for lease liabilities Operating leases $ 5,417 $ 1,096 Finance leases 1,296 2,624 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 219 $ 621 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — $ (86)
Leases	Leases The Company leases real estate, trucks and other equipment. The determination of whether an arrangement is, or contains, a lease is performed at the inception of the arrangement. Classification and initial measurement of the right-of-use asset and lease liability are determined at the lease commencement date. The Company elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets. Instead, the short-term leases are recognized in expense on a straight-line basis over the lease term. The Company's arrangements include certain non-lease components such as common area and other maintenance for leased real estate, as well as mileage, fuel and maintenance costs related to leased vehicles. For all leased asset classes, the Company has elected to not separate non-lease components from lease components and will account for each separate lease component and non-lease component associated with the lease as a single lease component. The Company does not guarantee any residual value in its lease agreements, and there are no material restrictions or covenants imposed by lease arrangements. Real estate leases typically include one or more options to extend the lease. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. For the Company’s leased vehicles, the Company uses the interest rate implicit in its leases with the lessor to discount lease payments at the lease commencement date. When the implicit rate is not readily available, as is the case with the Company’s real estate leases, the Company uses quoted borrowing rates on its secured debt. Related Party Lease Agreement. In conjunction with the closing of the Jake Marshall Transaction, the Company entered into an operating lease for certain land and facilities owned by a former member of JMLLC who became a full-time employee of the Company. The lease term is ten years and includes an option to extend the lease for two successive periods of two years each through November 2035. Base rent for the term of the lease is $37,500 per month for the first five years with payment commencing on January 1, 2022. The fixed rent payment is escalated to $45,000 per month for years 6 through 10 of the lease term. Fixed rent payments for the extension term shall be increased from $45,000 by the percentage increase, if any, in the consumer price index from the lease commencement date. In addition, under the agreement, the Company is required to pay its share of estimated property taxes and operating expenses, both of which are variable lease expenses. Southern California Sublease . In June, 2021, the Company entered into a sublease agreement with a third party for the entire ground floor of its leased space in Southern California, consisting of 71,787 square feet. Under the terms of the sublease agreement, the sublessee is obligated to pay the Company base rent of approximately $0.6 million per year, which is subject to a 3.0% annual rent increase, plus certain operating expenses and other costs. The initial lease term commenced in September 2021 and continues through April 30, 2027. As of December 31, 2021, the Company remains obligated under the original lease for such office space and, in the event the subtenant of such office space fails to satisfy its obligations under the sublease, the Company would be required to satisfy its obligations directly to the landlord under such original lease. For the year ended December 31, 2021, the Company recorded $0.4 million of income in selling, general and administrative expenses related to this sublease agreement. The following table summarizes the lease amounts included in the Company’s consolidated balance sheets as of December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Balance Sheets December 31, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 20,119 $ 18,751 Finance Property and equipment, net (b) 4,916 6,242 Total lease assets $ 25,035 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,366 $ 3,929 Finance Current portion of long-term debt 2,451 2,536 Noncurrent Operating Long-term operating lease liabilities 16,576 15,459 Finance Long-term debt 2,681 3,923 Total lease liabilities $ 26,074 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.9 million and $11.9 million at December 31, 2021 and 2020, respectively. (b) Finance lease assets are recorded net of accumulated amortization of $5.9 million and $5.3 million at December 31, 2021 and 2020, respectively. The following table summarizes the lease costs included in the Company’s consolidated statements of operations for the years ended December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Statements of Operations December 31, 2021 December 31, 2020 Operating lease cost Cost of revenue (a) $ 2,901 $ 3,527 Operating lease cost Selling, general and administrative (a) 2,223 1,483 Finance lease cost: Amortization Cost of revenue (b) 2,622 2,711 Interest Interest expense, net (b) 305 363 Total lease cost $ 8,051 $ 8,084 (a) Operating lease costs recorded in cost of sales includes $0.5 million and $0.7 million of variable lease costs for both the years ended December 31, 2021 and 2020, respectively. In addition, $0.4 million and $0.3 million of variable lease costs are included in selling, general and administrative expenses for the years ended December 31, 2021 and 2020, respectively. These variable costs consist of our proportionate share of operating expenses, real estate taxes, and utilities. (b) Finance lease costs recorded in cost of revenue includes $2.8 million and $2.4 million of variable leases costs for the years ended December 31, 2021 and 2020, respectively. These variable lease costs consist of fuel, maintenance, and sales tax charges. No variable lease costs for finance leases were recorded in selling, general and administrative expenses for the years ended December 31, 2021 or 2020. Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of the year ended December 31, 2021 were as follows (in thousands): Operating Leases Year ending December 31: Finance Non-Related Party Related Party (1) Sublease Receipts (2) Total Operating 2022 $ 2,658 $ 4,800 $ 450 $ (657) $ 4,593 2023 1,662 3,516 450 (677) 3,289 2024 851 2,917 450 (697) 2,670 2025 289 2,409 450 (718) 2,141 2026 12 2,010 450 (740) 1,720 Thereafter — 2,033 4,815 (250) 6,598 Total minimum lease payments $ 5,472 $ 17,685 $ 7,065 $ (3,739) $ 21,011 Amounts representing interest (340) Present value of net minimum lease payments $ 5,132 (1) Associated with the aforementioned related party lease entered into with a former member of JMLLC. (2) Associated with the aforementioned third party sublease. The following is a summary of the lease terms and discount rates as of: December 31, 2021 December 31, 2020 Weighted average lease term (in years) Operating 7.10 5.48 Finance 2.51 2.78 Weighted average discount rate Operating 4.68 % 4.83 % Finance 5.27 % 5.50 % The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Year Ended December 31, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 4,938 $ 5,164 Operating cash flows from finance leases 305 363 Financing cash flows from finance leases 2,623 2,664 Right-of-use assets exchanged for lease liabilities Operating leases $ 5,417 $ 1,096 Finance leases 1,296 2,624 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 219 $ 621 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — $ (86)

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Retirement Plan	Retirement PlanThe Company maintains a 401(k) plan for eligible, participating employees. The Company contributes an amount equal to 100% of an employee’s salary reduction contributions up to 4% of such employee’s compensation in a given year, as defined by the plan and subject to IRS limitations. The Company’s mandatory contributions were $2.3 million for the year ended December 31, 2021, as compared to $2.2 million for the year ended December 31, 2020. The Company may make a discretionary profit sharing contribution to the 401(k) plan in accordance with plan provisions. The Company has full discretion to determine whether to make such a contribution, and the amount of such contribution. In order to share in the profit sharing contribution, employees must have satisfied the 401(k) Plan’s eligibility requirements and be employed on the last day of the year. Employees are not required to contribute any money to the 401(k) Plan in order to qualify for the Company profit sharing contribution. Any discretionary profit sharing contribution would be divided among participants eligible to share in the contribution for the year in the same proportion that the participant’s pay bears to the total pay of all participants. This means the amount allocated to each eligible participant’s account would, as a percentage of pay, be the same. No discretionary profit sharing contributions were made for the years ended December 31, 2021 or 2020.

Multiemployer Pension Plans

Multiemployer Pension Plans	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Multiemployer Pension Plans	Multiemployer Pension Plans The Company participates in approximately 40 multiemployer pension plans (“MEPPs”) that provide pension benefits to certain union employees in accordance with various collective bargaining agreements (“CBAs”). As of December 31, 2021, approximately 51% of the Company’s employees are members of collective bargaining units. As one of many employers who are obligated to contribute to these MEPPs, the Company is responsible with the other participating employers for any unfunded pension liabilities. The Company’s contributions to a particular MEPP are established by the applicable CBAs; however, the Company’s required contributions to a MEPP may increase based on the funded status of the individual MEPP and the legal requirements of the Pension Protection Act of 2006 (the “PPA”), which requires substantially underfunded MEPPs to implement a funding improvement plan (“FIP”) or a rehabilitation plan (“RP”) to improve their funded status. Factors that could impact the funded status of a MEPP include, without limitation, investment performance, changes in participant demographics, a decline in the number of actively employed covered employees, a decline in the number of contributing employers, changes in actuarial assumptions and the utilization of extended amortization provisions. If a contributing employer stops contributing to a MEPP, the unfunded obligations of the MEPP may be borne by the remaining contributing employers. Assets contributed to an individual MEPP are pooled with contributions made by other contributing employers; the pooled assets will be used to provide benefits to the Company’s employees and the employees of the other contributing employers. A FIP or RP requires a particular MEPP to adopt measures to correct its underfunded status. These measures may include, but are not limited to an increase in a contributing employer’s contribution rate, or changes to the benefits paid to retirees. In addition, the PPA requires that a 5% surcharge be levied on employer contributions for the first year commencing shortly after the date the employer receives notice that the MEPP is in critical status and a 10% surcharge on each succeeding year until a CBA is in place with terms and conditions consistent with the RP. If a MEPP has unfunded pension liabilities, the Company could be obligated to make additional payments to a MEPP if the Company either ceases to have an obligation to contribute to the MEPP under a CBA or significantly reduces the Company’s contributions to the MEPP because they reduce the number of employees who are covered by the relevant MEPP for various reasons, including, but not limited to, layoffs or closure of a subsidiary. The amount of such payments (known as a complete or partial withdrawal liability) would equal the Company’s proportionate share of the MEPPs unfunded vested benefits. Based on the information available to the Company from the MEPPs, the Company believes that some of the MEPPs to which they contribute are underfunded and are in “critical” or “endangered” status as those terms are defined by the PPA. Due to uncertainty regarding future factors that could trigger withdrawal liability, as well as the absence of specific information regarding the MEPPs’ current financial situation, the Company is unable to determine (a) the amount and timing of any future withdrawal liability, if any, and (b) whether the Company’s participation in these MEPPs could have a material adverse impact on our financial condition, results of operations or liquidity. The nature and diversity of the Company’s business may result in volatility of the amount of contributions to a particular MEPP for any given period. That is because, in any given market, the Company could be working on a significant project and/or projects, which could result in an increase in the direct labor force and a corresponding increase in contributions to the MEPP(s) dictated by the applicable CBA. When that particular project(s) finishes and is not replaced, the level of direct labor would also decrease, as would the level of contributions to the particular MEPP(s). Additionally, the level of contributions to a particular MEPP could also be affected by the terms of the CBA, which could require at a particular time, an increase in the contribution rate and/or surcharges. Total contributions to the various union construction industry MEPP, welfare, training and other benefits programs in accordance with the CBAs were $36.3 million for the year ended December 31, 2021, as compared to $41.8 million for the year ended December 31, 2020. Of these amounts, total contributions to MEPPs accounted for $14.3 million and $16.1 million for the years ended December 31, 2021 and 2020, respectively. The following table presents the MEPPs in which the Company participates. Additionally, this table also lists the PPA Zone Status for MEPPs as the critical status (red zone-less than 65% funded), the endangered status (yellow-less than 80% funded), the seriously endangered status (orange-less than 80% funded and projects a credit balance deficit within seven years) or neither critical or endangered status (green-greater than 80% funded). The zone status represents the most recent available information for the respective MEPP, which is 2020 for the 2021 year. These dates may not correspond with the Company’s calendar year contributions. The zone status is based on information received from the MEPPs and is certified by the MEPPs’ actuaries. The “FIP/RP Status” column indicates MEPPs for which a financial improvement plan (FIP) or rehabilitation plan (RP) has been adopted or implemented. Pension Fund EIN/Pension PPA Zone Status FIP/RP Status Contributions (in Contributions Surcharge Expiration date 2021 2020 2021 2020 Heating, Piping and Refrigeration Pension Fund 52-1058013 / 001 Green Green N/A $ 851 $ 1,045 No No Jul-22 Plumbers Local No 98 Defined Benefit Pension Fund 38-3031916 / 001 Yellow Yellow Implemented 1,386 1,658 Yes No May-25 United Association National Pension Fund (2) 52-6152779 / 001 Yellow Yellow Implemented 700 947 No No Ranging from May-22 - Aug-26 Pipefitters Local 636 Defined Benefit Pension Fund 38-3009873 / 001 Yellow Yellow Implemented 1,437 1,206 No No May-22 Sheet Metal Workers' Pension Plan of Southern California, Arizona and Nevada 95-6052257 / 001 Yellow Yellow Implemented 297 1,322 No No Jun-24 Sheet Metal Workers' National Pension Fund 52-6112463 / 001 Yellow Yellow Implemented 701 1,144 No No Ranging from May-23 – Apr-26 Sheet Metal Workers Local Union No. 80 Pension Fund 38-6105633 / 001 Green Yellow Implemented 1,571 1,383 Yes No May-26 Sheet Metal Workers Local 98 Pension Fund 31-6171213 / 001 Green Green Implemented 1,003 945 Yes No May 23 Steamfitters Local Union No. 420 Pension Fund 23-2004424 / 001 Red Red Implemented 526 591 No No Apr-23 Pipefitters Union Local No. 537 Pension Fund 51-6030859 / 001 Green Green N/A 1,805 1,337 No No Aug-25 Plumbers & Pipefitters Local No 189 Pension Plan 31-0894807 / 001 Green Green N/A 489 598 Yes No May-22 Plumbers & Pipefitters of Local Union No. 333 Pension Fund 38-3545518 / 005 Green Green Implemented 1,694 1,329 Yes No May-22 Southern California Pipe Trades Retirement Fund 51-6108443 / 001 Green Green N/A 161 662 No No Aug-26 Electrical Workers Local No. 26 Pension Trust Fund 52-6117919 / 001 Green Green N/A 429 348 No No May-24 Plumbers Union Local No. 12 Pension 04-6023174 / 001 Green Green N/A 131 261 No No Aug-25 Sheet Metal Workers Local 7, Zone 1 Pension Plan 38-6234066 / 001 Green Yellow Implemented 293 383 No No Apr-26 Plumbers & Steamfitters Local 577 Pension Plan 31-6134953 /001 Yellow Yellow Implemented 277 208 No No May-23 Plumbers Local Union No. 690 Pension Fund 23-6405018 / 001 Green Green N/A 53 147 No No Apr-24 Laborers District Council Pension and Disability Trust Fund No. 2 52-0749130 / 001 Yellow Yellow Implemented 33 37 No No Oct-21 National Electrical Benefit Fund 53-0181657 / 001 Green Green N/A 1 111 No No May-24 Airconditioning and Refrigeration Industry Retirement Trust Fund 95-6035386 / 001 Green Green N/A 130 144 No No Aug-24 Plumbers and Steamfitters Local 486 Pension Fund 52-6124449 / 001 Green Green N/A 15 40 No No Dec-22 Steamfitters Local #449 Pension Plan 25-6032401 / 001 Green (1) Green N/A 68 109 No No May-23 United Association Local Union No. 322 Pension Plan 21-6016638 / 001 Red Red Implemented 24 18 No Yes Apr-24 Sheet Metal Workers Local 224 Pension Fund 31-6171353 / 001 Yellow (1) Yellow Implemented 21 20 No No May-24 Plumbers Local 27 Pension Fund 25-6034928 / 001 Green (1) Green N/A — 18 No No May-23 Plumbers and Pipefitters Local Union No. 43 Pension Fund 62-6101288 / 001 Green Green Implemented 95 — Yes No June-24 All other plans (15 and 11 as of December 31, 2021 and 2020, respectively) 127 98 Total Contributions $ 14,318 $ 16,109 (1) Funding status based off of the prior year funding notice as the current year’s funding notice was not available prior to the filing of this Annual Report on Form 10-K. (2) Formerly the Plumbers and Pipefitters National Pension Fund.

Management Incentive Plans

Management Incentive Plans	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Management Incentive Plans	Management Incentive PlansThe Company initially adopted the Omnibus Incentive Plan on July 20, 2016 for the purpose of: (a) encouraging the profitability and growth of the Company through short-term and long-term incentives that are consistent with the Company’s objectives; (b) giving participants an incentive for excellence in individual performance; (c) promoting teamwork among participants; and (d) giving the Company a significant advantage in attracting and retaining key employees, directors and consultants. To accomplish such purposes, the Omnibus Incentive Plan, and such subsequent amendments to the Omnibus Incentive Plan (discussed herein), provides that the Company may grant options, stock appreciation rights, restricted shares, RSUs, performance-based awards (including performance-based restricted shares and restricted stock units), other share based awards, other cash-based awards or any combination of the foregoing. Following the approval of the 2021 Amended and Restated Omnibus Incentive Plan, the Company has reserved 2,250,000 shares of its common stock for issuance under the Restated 2016 Plan. The number of shares issued or reserved pursuant to the Omnibus Incentive Plan will be adjusted by the plan administrator, as they deem appropriate and equitable, as a result of stock splits, stock dividends, and similar changes in the Company’s common stock. In connection with the grant of an award, the plan administrator may provide for the treatment of such award in the event of a change in control. All awards are made in the form of shares only. Service-Based Awards The Company grants service-based stock awards in the form of RSUs. Service-based RSUs granted to executives, employees, and non-employee directors vest ratably, on an annual basis, over three years. The grant date fair value of the service-based awards was equal to the closing market price of the Company’s common stock on the date of grant. The following table summarizes our service-based RSU activity: Awards Weighted-Average Unvested at January 1, 2020 328,575 $ 7.83 Granted 178,633 2.64 Vested (211,300) 8.12 Forfeited (10,109) 6.80 Unvested at December 31, 2020 285,799 $ 6.32 Granted 127,407 11.99 Vested (144,784) 7.35 Forfeited (2,333) 8.27 Unvested at December 31, 2021 266,089 $ 8.45 Performance-Based Awards The Company grants performance-based restricted stock units (“PRSUs”) under which shares of the Company’s common stock may be earned based on the Company’s performance compared to defined metrics. The number of shares earned under a performance award may vary from zero to 150% of the target shares awarded, based upon the Company’s performance compared to the metrics. The metrics used for the grant are determined by the Company’s Compensation Committee of the Board of Directors and are based on internal measures such as the achievement of certain predetermined adjusted EBITDA, EPS growth and EBITDA margin performance goals over a 3-year period. The Company recognizes stock-based compensation expense for these awards over the vesting period based on the projected probability of achievement of the performance conditions as of the end of each reporting period during the performance period and may periodically adjust the recognition of such expense, as necessary, in response to any changes in the Company’s forecasts with respect to the performance conditions. During the years ended December 31, 2021 and 2020, the Company granted 185,367 and 96,500 PRSUs, respectively, to its executives and certain employees under the Restated 2016 Plan. For PRSUs granted in 2018, the Company did not recognize any stock-based compensation expense to-date related to these awards based on the Company’s determination that achievement of the minimum performance goal was not probable as of each reporting period. As such, these PRSUs were forfeited as of December 31, 2020. The following table summarizes our PRSU activity: Awards Weighted-Average Unvested at January 1, 2020 62,307 $ 12.62 Granted 96,500 3.67 Vested — — Forfeited (59,307) 12.95 Unvested at December 31, 2020 99,500 $ 4.23 Granted 185,367 12.26 Vested — — Forfeited (4,167) 8.92 Unvested at December 31, 2021 280,700 $ 9.46 Market-Based Awards On September 4, 2020, the Compensation Committee of the Board of Directors of the Company approved amendments to certain RSUs initially awarded on August 30, 2017 by the Company to certain employees. Pursuant to the amendment adopted on September 4, 2020, the measurement period was extended to July 16, 2022. In addition to the market performance-based vesting condition, the vesting of such restricted stock unit is subject to continued employment from August 1, 2017 through the later of July 31, 2019 or the date on which the Compensation Committee certifies the achievement of the performance goal. The Company has accounted for this amendment as a Type I modification and will recognize approximately $0.2 million of incremental stock-based compensation expense over 1.26 years based on an updated Monte Carlo simulation model. The following table summarizes our MRSU activity for the fiscal years ended December 31, 2021 and 2020: Awards Weighted-Average Unvested at January 1, 2020 125,000 $ 6.58 Granted — — Vested — — Forfeited (22,500) 6.58 Unvested at December 31, 2020 102,500 $ 8.26 Granted — — Vested — — Forfeited — — Unvested at December 31, 2021 102,500 $ 8.26 The table below sets forth the assumptions used within the initial Monte Carlo simulation model to value the MRSU awards: Risk-free interest rate 1.56 % Dividend yield 0 % Remaining performance period (years) 3.92 Expected volatility 28.54 % Estimated grant date fair value (per share) $ 6.58 Derived service period (years) 1.96 Total recognized stock-based compensation expense amounted to $2.6 million and $1.1 million for the years ended December 31, 2021 and 2020, respectively. The aggregate fair value as of the vest date of RSUs that vested during the years ended December 31, 2021 and 2020 was $1.6 million and $1.1 million, respectively. Total unrecognized stock-based compensation expense related to unvested RSUs which are probable of vesting amounted to $2.3 million at December 31, 2021. These costs are expected to be recognized over a weighted average period of 1.75 years.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsSouthern California Region. In February 2022, the Company announced its strategic decision to wind down its Southern California GCR and ODR operations. The decision was made to better align the Company’s customer geographic focus and to reduce losses related to unprofitable locations. The Company expects to fully exit the Southern California Region in 2022.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) and based on the assumption that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities in the normal course of business.
Principles of Consolidation	Principles of Consolidation References in these financial statements to the Company refer collectively to the accounts of Limbach Holdings, Inc. and its wholly-owned subsidiaries, including LHLLC, Limbach Facility Services LLC (“LFS”), Limbach Company LLC, Limbach Company LP, Harper Limbach LLC, Harper Limbach Construction LLC, Limbach Facility & Project Solutions LLC, Jake Marshall, LLC (“JMLLC”) and Coating Solutions, LLC (“CSLLC”) for all periods presented, unless otherwise indicated. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements for assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of revenue and expenses during the reported period, and the accompanying notes. Management believes that its most significant estimates and assumptions have been based on reasonable and supportable assumptions and the resulting estimates are reasonable for use in the preparation of the consolidated financial statements. The Company’s significant estimates include estimates associated with revenue recognition on construction contracts, costs incurred through each balance sheet date, impairment of goodwill, intangibles, property and equipment, fair valuation in business combinations, insurance reserves, income tax valuation allowances, and contingencies. If the underlying estimates and assumptions upon which the consolidated financial statements are based change in the future, actual amounts may differ from those included in the accompanying consolidated financial statements.
Cash and Cash Equivalents	Cash and Cash EquivalentsCash and cash equivalents consist principally of currency on hand and demand deposits at commercial banks. The Company maintains demand accounts at several domestic banks. The Company's cash balances with financial institutions typically exceed the Federal Deposit Insurance Corporation (“FDIC”) coverage limit of $0.25 million.
Restricted Cash	Restricted Cash Restricted cash is cash held at a commercial bank in an imprest account held for the purpose of funding workers’ compensation and general liability claims against the Company. This amount is replenished either when depleted or at the beginning of each month.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful AccountsThe carrying value of the receivables, net of the allowance for doubtful accounts, represents their estimated net realizable value. Management provides for probable uncollectible accounts through a charge to earnings and a credit to the valuation account based on its assessment of the current status of individual accounts, type of service performed, and current economic conditions. Balances that are still outstanding after management has used reasonable collection efforts are written off through a charge to the valuation allowance and an adjustment of the account receivable. The majority of customer balances at each balance sheet date are collected within twelve months. As is common practice in the industry, the Company classifies all accounts receivable as current assets. Based on assessments by management, allowances for doubtful accounts were approximately $0.3 million at both December 31, 2021 and 2020.
Joint Ventures	Joint Ventures The Company accounts for its participation in certain special purpose, project specific joint ventures under the equity method of accounting. The Company’s entry into these joint ventures is for the purpose of bidding, negotiating and completing specific projects. The Company and its joint venture partner(s) separately enter into their own sub-contracts with the joint venture for each party’s respective portion of the work. All revenue and expenses and the related contract assets and liabilities related to the Company’s sub-contract are recorded within the Company’s statements of operations and balance sheets, similarly to any other construction project. The joint venture itself does not accumulate any profits or losses, as the joint venture revenue is equal to the sum of the sub-contracts it issues to the joint venture partners. The voting power and management of the joint ventures are shared equally by the joint venture partners, qualifying these entities for joint venture treatment under GAAP. The shared voting power and management responsibilities allow the Company to exercise significant influence without controlling the joint venture entity. As such, the Company applies the equity method of accounting as defined in ASC Topic 323, Investments – Equity Method and Joint Ventures .
Revenue Recognition	Revenue Recognition The Company’s revenue is primarily derived from construction-type and service contracts that generally range from six months to two years. The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers . ASC Topic 606 provides for a five-step model for recognizing revenue from contracts with customers as follows: 1. Identify the contract 2. Identify performance obligations 3. Determine the transaction price 4. Allocate the transaction price 5. Recognize revenue Identify the contract with a customer. A contract with a customer exists when: (a) the parties have approved the contract and are committed to perform their respective obligations, (b) the rights of the parties can be identified, (c) payment terms can be identified, (d) the arrangement has commercial substance, and (e) collectability of consideration is probable. Judgment is required when determining if the contractual criteria are met, specifically in the earlier stages of a project when a formally executed contract may not yet exist. In these situations, the Company evaluates all relevant facts and circumstances, including the existence of other forms of documentation or historical experience with our customers that may indicate a contractual agreement is in place and revenue should be recognized. In determining if the collectability of consideration is probable, the Company considers the customer’s ability and intention to pay such consideration through an evaluation of several factors, including an assessment of the creditworthiness of the customer and our prior collection history with such customer. Identify the performance obligations in the contract . At contract inception, the Company assesses the goods or services promised in a contract and identifies, as a separate performance obligation, each distinct promise to transfer goods or services to the customer. The identified performance obligations represent the “unit of account” for purposes of determining revenue recognition. In order to properly identify separate performance obligations, the Company applies judgment in determining whether each good or service provided is: (a) capable of being distinct, whereby the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer, and (b) distinct within the context of the contract, whereby the transfer of the good or service to the customer is separately identifiable from other promises in the contract. Determine the transaction price. The transaction price represents the amount of consideration to which the Company expects to be entitled in exchange for transferring promised goods or services to our customers. The consideration promised within a contract may include fixed amounts, variable amounts, or both. To the extent the performance obligation includes variable consideration, the Company estimates the amount of variable consideration to be included in the transaction price utilizing one of two prescribed methods, depending on which method better predicts the amount of consideration to which the entity will be entitled. Such methods include: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current, and estimates of future performance. The expected value method is typically utilized in situations where a contract contains a large number of possible outcomes while the most likely amount method is typically utilized in situations where a contract has only two possible outcomes. Variable consideration is included in the transaction price only to the extent it is probable, in the Company’s judgment, that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur when the uncertainty associated with the variable consideration is subsequently resolved. This threshold is referred to as the variable consideration constraint. In assessing whether to apply the variable consideration constraint, the Company considers if factors exist that could increase the likelihood or the magnitude of a potential reversal of revenue, including, but not limited to, whether: (a) the amount of consideration is highly susceptible to factors outside of the Company’s influence, such as the actions of third parties, (b) the uncertainty surrounding the amount of consideration is not expected to be resolved for a long period of time, (c) the Company’s experience with similar types of contracts is limited or that experience has limited predictive value, (d) the Company has a practice of either offering a broad range of price concessions or changing the payment terms and conditions of similar contracts in similar circumstances, and (e) the contract has a large number and broad range of possible consideration amounts. Pending change orders represent one of the most common forms of variable consideration included within contract value and typically represent contract modifications for which a change in scope has been authorized or acknowledged by our customer but the final adjustment to contract price is yet to be negotiated. In estimating the transaction price for pending change orders, the Company considers all relevant facts, including documented correspondence with the customer regarding acknowledgment of and/or agreement with the modification, as well as historical experience with the customer or similar contractual circumstances. Based upon this assessment, the Company estimates the transaction price, including whether the variable consideration constraint should be applied. Contract claims are another form of variable consideration which is common within our industry. Claim amounts represent revenue that has been recognized for contract modifications that are not submitted or are in dispute as to both scope and price. In estimating the transaction price for claims, the Company considers all relevant facts available. However, given the uncertainty surrounding claims, including the potential long-term nature of dispute resolution and the broad range of possible consideration amounts, there is an increased likelihood that any additional contract revenue associated with contract claims is constrained. The resolution of claims involves negotiations and, in certain cases, litigation. In the event litigation costs are incurred by us in connection with claims, such litigation costs are expensed as incurred, although we may seek to recover these costs. Allocate the transaction price to performance obligations in the contract. For contracts that contain multiple performance obligations, the Company allocates the transaction price to each performance obligation based on a relative standalone selling price. The Company determines the standalone selling price based on the price at which the performance obligation would have been sold separately in similar circumstances to similar customers. If the standalone selling price is not observable, the Company estimates the standalone selling price taking into account all available information such as market conditions and internal pricing guidelines. In certain circumstances, the standalone selling price is determined using an expected profit margin on anticipated costs related to the performance obligation. Recognize revenue as performance obligations are satisfied. Throughout the execution of our construction-type contracts, the Company recognizes revenue with the continuous transfer of control to the customer. The customer typically controls the asset under construction by either contractual termination clauses or by the Company’s rights to payment for work already performed on the asset under construction that does not have an alternative use for the Company. Because control transfers over time, revenue is recognized to the extent of progress towards completion of the performance obligations. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services provided. The Company generally uses the cost-to-cost method for its contracts, which measures progress towards completion for each performance obligation based on the ratio of costs incurred to date to the total estimated costs at completion for the respective performance obligation. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Revenue, including estimated profits, is recorded proportionately as costs are incurred. Cost of operations includes labor, materials, subcontractor costs, and other direct and indirect costs, including depreciation and amortization. Certain construction-type contracts include retention provisions to provide assurance to our customers that we will perform in accordance with the contract terms and are not considered a financing benefit. The balances billed but not paid by customers pursuant to these provisions generally become due upon completion and acceptance of the project work by the customer. The Company has determined there are no significant financing components in our contracts during the years ended December 31, 2021 and 2020. For our service-type contracts, revenue is also generally recognized over time as the customer simultaneously receives and consumes the benefits of our performance as we perform the service. For our fixed price service-type contracts with specified service periods, revenue is generally recognized on a straight-line basis over such service period when our inputs are expended evenly, and the customer receives and consumes the benefits of our performance throughout the contract term. Due to uncertainties inherent in the estimation process, it is possible that estimates of costs to complete a performance obligation will be revised in the near-term. For those performance obligations for which revenue is recognized using a cost-to-cost input method, changes in total estimated costs, and related progress towards complete satisfaction of the performance obligation, are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. When the current estimate of total costs for a performance obligation indicate a loss, a provision for the entire estimated loss on the unsatisfied performance obligation is made in the period in which the loss becomes evident. Costs to fulfill our contracts (“pre-bid costs”) that are not expected to be recovered from the customer are expensed as incurred and included in selling, general and administrative expenses on our consolidated statements of operations. In accordance with industry practice, we classify as current all assets and liabilities relating to the performance of contracts. See Note 4 – Revenue from Contracts with Customers for further information. Changes in Estimates on Construction Contracts The accuracy of our revenue and profit recognition in a given period depends on the accuracy of our estimates of the cost to complete each project. There are a number of factors that can contribute to changes in estimates of contract cost and profitability. The most significant of these include: • The completeness and accuracy of the original bid; • costs associated with scope changes; • expected, or actual, resolution terms for claims; • achievement of contract incentives; • changes in costs of labor and/or materials; • extended overhead and other costs due to owner, weather and other delays; • subcontractor performance issues; • changes in productivity expectations; • site conditions that differ from those assumed in the original bid; • changes from original design on design-build projects; • the availability and skill level of workers in the geographic location of the project; • a change in the availability and proximity of equipment and materials; • our ability to fully and promptly recover on claims and back charges for additional contract costs, and • the customer's ability to properly administer the contract. Subsequent to the inception of a construction-type contract in our GCR and ODR segments, the transaction price could change for various reasons, including the executed or estimated amount of change orders and unresolved contract modifications and claims to or from owners. Changes that are accounted for as an adjustment to existing performance obligations are allocated on the same basis at contract inception. Otherwise, changes are accounted for as separate performance obligation(s) and the separate transaction price is allocated. Changes are made to the transaction price from unapproved change orders to the extent the amount can be reasonably estimated and recovery is probable. On certain projects, we have submitted and have pending unresolved contract modifications and claims to recover additional costs and the associated profit, if applicable, to which we believe we are entitled under the terms of contracts with customers, subcontractors, vendors or others. The owners or their authorized representatives and/or other third parties may be in partial or full agreement with the modifications or claims, or may have rejected or disagree entirely or partially as to such entitlement. Changes are made to the transaction price from affirmative claims with customers to the extent that additional revenue on a claim settlement with a customer is probable and estimable. A reduction to costs related to claims with non-customers with whom we have a contractual arrangement (“back charges”) is recognized when the estimated recovery is probable and estimable. Recognizing claims and back charge recoveries requires significant judgments of certain factors including, but not limited to, dispute resolution developments and outcomes, anticipated negotiation results, and the cost of resolving such matters. The foregoing factors, as well as the stage of completion of contracts in process and the mix of contracts at different margins may cause fluctuations in gross profit and gross profit margin from period to period. Generally, if the contract is at an early stage of completion, the current period impact is smaller than if the same change in estimate is made to the contract at a later stage of completion. Significant changes in cost estimates, particularly in our larger, more complex projects have had, and can in future periods have, a significant effect on our profitability. Management evaluates changes in estimates on a contract by contract basis and discloses significant changes, if material, in the notes to the consolidated financial statements. The cumulative catch-up method is used to account for revisions in estimates. Provisions for estimated losses on uncompleted contracts are recognized in the period in which such losses are determined. Retainage receivable represents amounts invoiced to customers where payments have been partially withheld, typically 10%, pending the completion of certain milestones, satisfaction of other contractual conditions or the completion of the project. Retainage agreements vary from project to project and balances could be outstanding for several months or years depending on a number of circumstances such as contract-specific terms, project performance and other variables that may arise as the Company makes progress towards completion. Contract assets represent the excess of contract costs and profits (or contract revenue) over the amount of contract billings to date and are classified as a current asset. Contract assets result when either: (1) the appropriate contract revenue amount has been recognized over time in accordance with ASC Topic 606, but a portion of the revenue recorded cannot be currently billed due to the billing terms defined in the contract, or (2) costs are incurred related to certain claims and unapproved change orders. Claims occur when there is a dispute regarding both a change in the scope of work and the price associated with that change. Unapproved change orders occur when a change in the scope of work results in additional work being performed before the parties have agreed on the corresponding change in the contract price. The Company routinely estimates recovery related to claims and unapproved change orders as a form of variable consideration at the most likely amount it expects to receive and to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Claims and unapproved change orders are billable upon the agreement and resolution between the contractual parties and after the execution of contractual amendments. Increases in claims and unapproved change orders typically result from costs being incurred against existing or new positions; decreases normally result from resolutions and subsequent billings. Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for which work has not been performed and exclude unexercised contract options. The Company’s remaining performance obligations includes projects that have a written award, a letter of intent, a notice to proceed or an agreed upon work order to perform work on mutually accepted terms and conditions.
Goodwill and Impairment of Long-Lived Assets	Goodwill and Impairment of Long-Lived Assets Goodwill is evaluated for impairment at least annually or whenever events or changes in circumstance indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company may perform either a qualitative assessment of potential impairment or proceed directly to a quantitative assessment of potential impairment. The Company's qualitative assessment of potential impairment may result in the determination that a quantitative impairment analysis is not necessary. Under this elective process, the Company assesses qualitative factors to determine whether the existence of events or circumstances leads the Company to determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If after assessing the totality of events or circumstances, the Company determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then a quantitative assessment is not required. However, if the Company concludes otherwise, a quantitative impairment analysis is performed. If the Company chooses not to perform a qualitative assessment, or if it chooses to perform a qualitative assessment but is unable to qualitatively conclude that no impairment has occurred, then the Company will perform a quantitative assessment. In the case of a quantitative assessment, the Company estimates the fair value of the reporting unit with which the goodwill is associated and compares it to the carrying value. If the estimated fair value of a reporting unit is less than its carrying value, an impairment charge is recognized for the excess of the reporting unit's carrying value over its fair value. See Note 5 – Goodwill and Intangible Assets for further detail. The Company evaluates long-lived assets for impairment when events or changes in circumstances indicate, in management's judgment, that the carrying value of such assets may not be recoverable. With respect to property, plant and equipment and finite lived intangibles, asset recoverability is measured by comparing the carrying value of the asset or asset group with its expected future pre-tax undiscounted cash flows. These cash flow estimates require the Company to make projections and assumptions for many years into the future for pricing, demand, competition, operating cost and other factors. If the carrying amount exceeds the expected future undiscounted cash flows, the Company recognizes an impairment equal to the excess of carrying value over fair value as determined by quoted market prices in active markets or present value techniques if quotes are unavailable. The determination of the fair value using present value techniques requires the Company to make projections and assumptions regarding the probability of a range of outcomes and the rates of interest used in the present value calculations. Any changes the Company makes to these projections and assumptions could result in significant revisions to its evaluations of recoverability and the recognition of additional impairments. See Note 5 – Goodwill and Intangible Assets for further discussion on impairments of long-lived assets.
Intangible Assets	Intangible Assets
Property and Equipment, net	Property and Equipment, net Property and equipment, with the exception of our fleet vehicle finance leases, are recorded at cost and depreciated on a straight-line basis over their estimated useful lives. For buildings and leasehold improvements, the Company’s useful lives range from 5 years to 40 years; for machinery and equipment, useful lives range from 3 years to 10 years. Expenditures for maintenance and repairs are expensed as incurred. Leasehold improvements for our real estate operating leases are amortized over the lesser of the term of the related lease or the estimated useful lives of the improvements.
Leases	Leases A lease contract conveys the right to use an underlying asset for a period of time in exchange for consideration. At inception, we determine whether a contract contains a lease by determining if there is an identified asset and if the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. Leases are classified as either operating or finance, based on our evaluation of certain criteria. With the exception of short-term leases (leases with an initial term of 12 months or less), at lease commencement, we measure and record a lease liability equal to the present value of the remaining lease payments, generally discounted using quoted borrowing rates on our secured debt as the implicit rate is not readily determinable on many of our real estate operating leases. For our fleet vehicles classified as financing leases, we use the stated interest rate in the lease. On the lease commencement date, the amount of the right-of-use (“ROU”) assets consist of the following: • the amount of the initial measurement of the lease liability; • any lease payment made at or before the commencement date, minus any lease incentives received; and • any initial direct costs incurred. Most of our operating lease contracts have the option to extend or renew. We assess the option for individual leases, and we generally consider the base term to be the term of lease contracts. See Note 13 – Leases for additional information. We periodically evaluate whether events and circumstances have occurred that indicate that the remaining balances of our ROU assets may not be recoverable. We use estimates of future undiscounted cash flows, as well as other economic and business factors, to assess the recoverability of these assets.
Deferred Financing Costs and Debt Discount	Deferred Financing Costs and Debt Discount Deferred financing costs are deferred and amortized to interest expense using the effective interest rate method over the term of the related long-term debt agreement, and the straight-line method for the revolving credit agreement. Debt issuance costs related to the issuance and/or extension, as applicable, of the Company’s term loans are reflected as a direct reduction from the carrying amount of long-term debt. Debt issuance costs related to revolving credit facilities are capitalized and reflected as an other asset. Prior to their extinguishment, the allocated fair value of the CB Warrants (defined in Note 7 ) were recorded as a debt discount and were accreted over the expected term of the debt as interest expense. See Note 7 – Debt for additional information.
Stock-Based Compensation	Stock-Based CompensationStock-based compensation awards granted to executives, employees, and non-employee directors are measured at fair value and recognized as an expense. For awards with service conditions only, the Company recognizes compensation expense on a graded vesting basis over the requisite service period for each separately vesting tranche of the award based on the closing market price of the Company’s common stock at the grant date. For awards with service and performance conditions, the Company recognizes compensation expense based on the closing market price of the Company’s common stock at the grant date using the straight-line method over the requisite service period. Estimates of compensation expense for an award with performance conditions are based on the probable outcome of the performance conditions. The cumulative effect of changes in the probability outcomes are recorded in the period in which the changes occur. For awards with market-based conditions (“MRSUs”), the Company uses a Monte Carlo simulation model to estimate the grant-date fair value. The fair value related to market-based awards is recorded as compensation expense using the graded vesting method regardless of whether the market condition is achieved or not. The Company has elected to account for forfeitures as they occur to determine the amount of compensation expense to be recognized each period.
Income Taxes	Income Taxes The provision for income taxes includes federal, state and local taxes. The Company accounts for income taxes in accordance with ASC Topic 740 - Income Taxes , which requires the use of the asset and liability method. Under this method, deferred tax assets and liabilities and income or expense is recognized for the expected future tax consequences of temporary differences between the financial statement carrying values and their respective tax bases, using enacted tax rates expected to be applicable in the years in which the temporary differences are expected to reverse. Changes in tax rates are recorded to deferred tax assets and liabilities and reflected in the provision for income taxes during the period that includes the enactment date. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of the deferred tax assets will not be realized. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected, scheduling of anticipated reversals of taxable temporary differences, and considering prudent and feasible tax planning strategies. Any interest or penalties incurred related to unrecognized tax benefits are recorded as tax expense in the provision for income tax expense line item of the accompanying consolidated statements of operations. The consolidated financial statements reflect expected future tax consequences of such positions presuming the taxing authorities have full knowledge of the position and all relevant facts, but without considering time values.
Fair Value Measurements	Fair Value Measurements The Company measures the fair value of financial assets and liabilities in accordance with ASC Topic 820 - Fair Value Measurements and Disclosures , which defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. ASC Topic 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to measurements involving significant unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are as follows: • Level 1 — inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that are accessible at the measurement date; • Level 2 — inputs other than quoted prices included in Level 1 that are observable for the asset or liability either directly or indirectly such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of assets or liabilities; and • Level 3 — unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. The Company believes that the carrying amounts of its financial instruments, including cash and cash equivalents, trade accounts receivable, and accounts payable, consist primarily of instruments without extended maturities, which approximate fair value primarily due to their short-term maturities and low risk of counterparty default. We also believe that the carrying value of the A&R Wintrust Term Loan (defined in Note 7 ) approximates its fair value due to the variable rate on such debt. As of December 31, 2021, the Company determined that the fair value of the A&R Wintrust Term Loan was $34.9 million. This fair value was determined using discounted estimated future cash flows using level 3 inputs. There were no outstanding borrowings on the Company’s A&R Wintrust Revolving Loan (defined in Note 7) at December 31, 2021. Prior to its termination as a result of the 2021 Refinancing (defined in Note 7 ) , the fair value of the Company's CB Warrants were determined using the Black-Scholes-Merton option pricing model. The valuation inputs included the quoted price of the Company’s common stock in an active market, volatility and expected life of the warrants, which were considered Level 3 inputs. The CB Warrants liability was included in other long-term liabilities on the Company's December 31, 2020 Consolidated Balance Sheet. The Company remeasured the fair value of the CB Warrants liability as of December 31, 2020 and February 24, 2021 and recorded any adjustments to other income (expense). At both February 24, 2021 and December 31, 2020, the CB Warrants liability was $2.0 million. Due to the extinguishment of the CB Warrants on the 2021 Refinancing Date, there was no liability associated with the CB Warrants recorded as of December 31, 2021. For the period from January 1, 2021 through the 2021 Refinancing Date, the Company recorded other income of $0.1 million to reflect the change in the fair value of the CB Warrants liability. For the year ended December 31, 2020, the Company recorded other expense of $1.6 million to reflect the change in the CB Warrants liability.
Recently Adopted Accounting Standards and Recent Accounting Pronouncements	Recently Adopted Accounting Standards In November 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which creates an exception to the general recognition and measurement principle for contract assets and contract liabilities from contracts with customers acquired in a business combination. Under this exception, an acquirer applies ASC 606, Revenue from Contracts with Customers , to recognize and measure contract assets and contract liabilities on the acquisition date. ASC 805 generally requires the acquirer in a business combination to recognize and measure the assets it acquires and the liabilities it assumes at fair value on the acquisition date. The changes are effective for annual periods beginning after December 15, 2022. The Company early adopted ASU 2021-08 in December 2021. The contract assets and contract liabilities associated with the Jake Marshall Transaction have been valued in accordance with this standard. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) , which affects general principles within Topic 740, and is meant to simplify and reduce the cost of accounting for income taxes. It removes certain exceptions to the general principles in Topic 740 and simplifies areas including franchise taxes that are partially based on income, transactions with a government that result in a step up in the tax basis of goodwill, the incremental approach for intraperiod tax allocation, interim period income tax accounting for year-to-date losses that exceed anticipated losses and enacted changes in tax laws in interim periods. The changes are effective for annual periods beginning after December 15, 2020. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements or presentation thereof. Also in October 2020, the FASB issued ASU 2020-10, Codification Improvements . The amendments in this update remove references to various FASB Concepts Statements, situates all disclosure guidance in the appropriate disclosure section of the Codification, and makes other improvements and technical corrections to the Codification. The amendments in Sections B and C of this amendment are effective for annual periods beginning after December 15, 2020, for public business entities, with early adoption permitted. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements or presentation thereof. Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) , Measurement of Credit Losses on Financial Instruments, which introduced an expected credit loss methodology for the measurement and recognition of credit losses on most financial instruments, including trade receivables and off-balance sheet credit exposure. Under this guidance, an entity is required to consider a broader range of information to estimate expected credit losses, which may result in earlier recognition of losses. This ASU also requires disclosure of information regarding how a company developed its allowance, including changes in the factors that influenced management’s estimate of expected credit losses and the reasons for those changes. The guidance is effective for smaller reporting companies on January 1, 2023 with early adoption permitted. The adoption of this standard will be through a cumulative-effect adjustment to retained earnings as of the effective date. Based on its historical experience, the Company does not expect that this pronouncement will have a significant impact in its financial statements or on the estimate of the allowance for doubtful accounts. The FASB has issued ASU 2020-04, Reference Rate Reform (Topic 848) : Facilitation of the Effects of Reference Rate Reform on Financial Reporting in March 2020. This new guidance provides optional expedients for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform, on financial reporting. The risk of termination of the London Interbank Offered Rate (LIBOR), has caused regulators to undertake reference rate reform initiatives to identify alternative reference rates that are more observable or transaction based that are less susceptible to manipulation. ASU 2020-04 is effective between March 12, 2020 and December 31, 2022. In addition, in January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848) : Scope. The amendments in this update refine the scope for certain optional expedients and exceptions for contract modifications and hedge accounting to apply to derivative contracts and certain hedging relationships affected by the discounting transition. The amendments in this update are effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating the impact of adopting the reference rate reform guidance (both ASU 2020-04 and ASU 2021-01) on its consolidated financial statements. As discussed in Note 7, the A&R Credit Agreement removed LIBOR as a benchmark rate and now utilizes SOFR (as defined in the A&R Credit Agreement) as its replacement. In August 2020, the FASB issued ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40) : Accounting for Convertible Instruments and Contracts in an Entity's Own Equity, which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity and amends the scope guidance for contracts in an entity's own equity. The ASU addresses how convertible instruments are accounted for in the calculation of diluted earnings per share by using the if-converted method. The guidance is effective for all entities for fiscal years beginning after March 31, 2024, albeit early adoption is permitted no earlier than fiscal years beginning after December 15, 2020. Management is currently assessing the impact of this pronouncement on its consolidated financial statements.
Earnings per Share	Earnings per Share The Company calculates earnings per share in accordance with ASC Topic 260 - Earnings Per Share (“EPS”) . Basic earnings per common share applicable to common stockholders is computed by dividing earnings applicable to common stockholders by the weighted-average number of common shares outstanding and assumed to be outstanding. Diluted EPS assumes the dilutive effect of outstanding common stock warrants, shares issued in conjunction with the Company’s ESPP (defined in Note 9) and restricted stock units (“RSUs”), all using the treasury stock method.
Operating Segments	Operating SegmentsAs discussed in Note 1, on January 1, 2021, the Company renamed its two operating segments to reflect the Company's two distinct approaches to its customer base and to better align with its owner direct strategy. The previously named Construction segment is now known as GCR and the previously named Service segment is now known as ODR. These segments are reflective of how the Company’s Chief Operating Decision Maker (“CODM”) reviews operating results for the purposes of allocating resources and assessing performance. The Company's CODM is comprised of its Chief Executive Officer, Chief Financial Officer and Chief Operating Officer. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. The CODM evaluates performance based on income from operations of the respective branches after the allocation of Corporate office operating expenses. In accordance with ASC Topic 280 – Segment Reporting

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Company’s consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: (in thousands) December 31, 2021 December 31, 2020 Cash and cash equivalents $ 14,476 $ 42,147 Restricted cash 113 113 Total cash, cash equivalents and restricted cash $ 14,589 $ 42,260
Schedule of Property and Equipment	The following table summarizes the Company’s property and equipment: ( in thousands ) December 31, 2021 December 31, 2020 Land and improvements $ 400 $ 400 Buildings and leasehold improvements 10,721 7,751 Machinery and equipment 24,600 21,647 Finance leases - vehicles (1) 10,771 11,505 Gross property and equipment 46,492 41,303 Less: Accumulated amortization on finance leases (5,855) (5,263) Less: Accumulated depreciation (19,016) (16,340) Property and equipment, net of accumulated amortization and depreciation (2) $ 21,621 $ 19,700 (1) See additional information provided in Note 13 – Leases.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Schedule of Allocation of Fair Value of Assets and Liabilities from Jake Marshall Transaction	The following table summarizes the allocation of the fair value of the assets and liabilities of the Jake Marshall Transaction as of the Effective Date by the Company. (in thousands) Purchase Price Allocation Consideration: Cash $ 21,313 Earnout provision 3,089 Total Consideration 24,402 Fair value of assets acquired: Cash and cash equivalents 2,336 Accounts receivable 7,165 Contract assets 1,711 Other current assets 164 Property and equipment 5,762 Intangible assets 5,710 Amount attributable to assets acquired 22,848 Fair value of liabilities assumed: Accounts payable, including retainage 2,655 Accrued expenses and other current liabilities 570 Contract liabilities 462 Amount attributable to liabilities assumed 3,687 Goodwill $ 5,241
Schedule of Intangible Assets Acquired	Intangible assets, net as of December 31, 2021 are detailed below. (in thousands) Gross Carrying Amount Accumulated Amortization Net Intangible Assets Weighted Average Useful Life (Years) Trade name $ 1,150 $ (15) $ 1,135 6.2 Customer relationships - GCR 570 (6) 564 7.1 Customer relationships - ODR 3,050 (34) 3,016 7.6 Backlog - GCR 260 (14) 246 1.6 Backlog - ODR 680 (36) 644 1.6 Total $ 5,710 $ (105) $ 5,605 6.3
Schedule of Unaudited Pro Forma Information	The following unaudited pro forma combined financial information presents the Company's results as though the Jake Marshall Transaction had been completed at January 1, 2020. The pro forma combined financial information has been included for comparative purposes and is not necessarily indicative of the results that might have actually occurred had the Jake Marshall Transaction taken place on January 1, 2020; furthermore, the financial information is not intended to be a projection of future results. Year Ended December 31, (in thousands) (unaudited) 2021 2020 Pro forma revenue $ 523,479 $ 599,013 Pro forma net income $ 5,392 $ 4,310 Pro forma EPS (basic) $ 0.54 $ 0.55 Pro forma EPS (diluted) $ 0.53 $ 0.53

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Components of Contract Asset and Liability Balances	The components of the contract asset balances as of the respective dates were as follows: (in thousands) December 31, 2021 December 31, 2020 Change Contract assets Costs in excess of billings and estimated earnings $ 47,447 $ 31,894 $ 15,553 Retainage receivable 36,416 35,204 1,212 Total contract assets $ 83,863 $ 67,098 $ 16,765 (in thousands) December 31, 2021 December 31, 2020 Change Contract liabilities Billings in excess of costs and estimated earnings $ 26,293 $ 46,020 $ (19,727) Provisions for losses 419 628 (209) Total contract liabilities $ 26,712 $ 46,648 $ (19,936)
Schedule of Contracts in Progress	The net underbilling (overbilling) position for contracts in process consisted of the following: (in thousands) December 31, 2021 December 31, 2020 Revenue earned on uncompleted contracts $ 758,450 $ 752,564 Less: Billings to date (737,296) (766,690) Net underbilling (overbilling) $ 21,154 $ (14,126) (in thousands) December 31, 2021 December 31, 2020 Costs in excess of billings and estimated earnings $ 47,447 $ 31,894 Billings in excess of costs and estimated earnings (26,293) (46,020) Net underbilling (overbilling) $ 21,154 $ (14,126)
Schedule of Revisions in Contract Estimates	The following table summarizes the Company’s recorded revisions in its contract estimates for certain GCR and ODR projects for the years ended December 31, 2021 and 2020 (includes material gross profit changes of $0.25 million or more). For the Years Ended December 31, 2021 2020 (in thousands except project count ) Project count Project count Gross profit write-ups: GCR $ 5,663 12 $ 1,654 3 ODR — — — — Total gross profit write-ups $ 5,663 12 $ 1,654 3 Gross profit write-downs: GCR $ (5,958) 8 $ (10,379) 15 ODR (332) 1 — — Total gross profit write-downs $ (6,290) 9 $ (10,379) 15 Total gross profit write-downs, net $ (627) $ (8,725)

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	The following table summarizes the carrying amount of goodwill associated with the Company's segments for the years ended December 31, 2021 and 2020. (in thousands) GCR ODR Total Goodwill as of January 1, 2020 $ — $ 6,129 $ 6,129 Goodwill as of December 31, 2020 — 6,129 6,129 Goodwill associated with the Jake Marshall Transaction — 5,241 5,241 Goodwill as of December 31, 2021 $ — $ 11,370 $ 11,370
Schedule of Definite-lived and Indefinite-lived Intangible Assets	Definite-lived and indefinite-lived intangible assets consist of the following: (in thousands) Gross Accumulated Net intangible December 31, 2021 Amortized intangible assets: Customer relationships – GCR – Jake Marshall $ 570 $ (6) $ 564 Customer relationships – ODR – Jake Marshall 3,050 (35) 3,015 Customer relationships – ODR – Limbach 4,710 (3,475) 1,235 Favorable leasehold interests (1) – Limbach 190 (82) 108 Backlog – GCR – Jake Marshall 260 (14) 246 Backlog – ODR – Jake Marshall 680 (36) 644 Trade name – Jake Marshall 1,150 (15) 1,135 Total amortized intangible assets 10,610 (3,663) 6,947 Unamortized intangible assets: Trade name – Limbach (2) 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 20,570 $ (3,663) $ 16,907 (1) During the first quarter of 2021, the Company reduced the gross carrying amount and accumulated amortization associated with its favorable leasehold interests intangible asset by $0.3 million due to the lease termination of its Western Pennsylvania office associated with the intangible asset. (2) The Company has determined that its trade name has an indefinite useful life. The Limbach trade name has been in existence since the Company’s founding in 1901 and therefore is an established brand within the industry. (in thousands) Gross Accumulated Net intangible December 31, 2020 (1) Amortized intangible assets: Customer relationships – ODR – Limbach $ 4,710 $ (3,112) $ 1,598 Favorable leasehold interests – Limbach 530 (407) 123 Total amortized intangible assets 5,240 (3,519) 1,721 Unamortized intangible assets: Trade name – Limbach 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 15,200 $ (3,519) $ 11,681 (1) The Backlog - GCR - Limbach intangible asset previously shown at December 31, 2020 has been fully amortized. Accordingly, its gross carrying amount of $4.8 million and corresponding accumulated amortization of $4.8 million have been removed from the table.
Schedule of Estimated Remaining Useful Lives of Definite-lived Intangible Assets	The estimated remaining useful lives of definite-lived intangible assets are as follows: Intangible Asset Amortization Method Estimated Remaining Useful Customer relationships – GCR – Jake Marshall Straight line 7.0 Customer Relationships – ODR – Limbach Pattern of economic benefit 9.0 Customer Relationships – ODR – Jake Marshall Straight line 7.5 Favorable Leasehold Interests – Limbach Straight line 7.2 Backlog – GCR – Jake Marshall Straight line 1.5 Backlog – ODR – Jake Marshall Straight line 1.5 Trade name – Jake Marshall Straight line 6.1
Schedule of Estimated Amortization Expense	Estimated amortization expense is as follows for the years ending December 31: (in thousands) Estimated Amortization Expense 2022 $ 1,567 2023 1,211 2024 867 2025 830 2026 800 2027 and thereafter 1,672 Total $ 6,947

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities are comprised of the following: ( in thousand s) December 31, 2021 December 31, 2020 Accrued payroll and related liabilities $ 8,169 $ 7,975 Accrued bonus and commissions 7,352 7,652 Accrued insurance liabilities 719 1,008 Accrued job costs 3,772 3,131 Assurance-type warranty liabilities 3,310 4,056 Other accrued liabilities 1,122 925 Total $ 24,444 $ 24,747
Schedule of Reconciliation of Assurance-type Warranties	Our reconciliation of assurance-type warranties are as follows: ( in thousand s) December 31, 2021 December 31, 2020 Balance at the beginning of the period $ 4,056 $ 2,886 Accruals for warranties issued 432 687 Accruals related to pre-existing warranties (including changes in estimates) 401 1,856 Settlements made (1,579) (1,373) Balance at the end of the period $ 3,310 $ 4,056

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consists of the following obligations: ( in thousand s) December 31, 2021 December 31, 2020 A&R Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in December 2021) plus interest through February 2026 $ 34,881 $ — A&R Wintrust Revolving Loan — — 2019 Refinancing Term Loan – term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022 — 39,000 Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.55% to 6.45% through 2026 5,132 6,459 Total debt $ 40,013 $ 45,459 Less - Current portion of long-term debt (9,879) (6,536) Less - Unamortized discount and debt issuance costs (318) (2,410) Long-term debt $ 29,816 $ 36,513
Schedule of Maturities of Long-term Debt and Finance Leases	Maturities of long-term debt and finance leases at December 31, 2021 are as follows: ( in thousands ) 2022 $ 9,879 2023 8,997 2024 8,247 2025 7,710 2026 5,180 Total $ 40,013
Schedule of Applicable Margin and Fees Payable	The following is a summary of the applicable margin and commitment fees payable on the available A&R Wintrust Term Loan and A&R Wintrust Revolving Loan credit commitment: Level Senior Leverage Ratio Applicable Margin for Applicable Margin for Applicable Margin for Commitment Fee I Greater than 1.00 to 1.00 1.00 % 0.50 % 0.25 % II Less than or equal to 1.00 to 1.00 0.25 % — % 0.25 %

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of the basic and diluted earnings per share attributable to the Company's common stockholders for the years ended December 31, 2021 and 2020: For the Years Ended (in thousands, except per share amounts) December 31, 2021 December 31, 2020 EPS numerator: Net income $ 6,714 $ 5,807 EPS denominator: Weighted average shares outstanding – basic 10,013 7,865 Nonvested restricted stock units 215 191 Employee stock purchase plan 4 9 Weighted average shares outstanding – diluted 10,232 8,065 EPS: Basic $ 0.67 $ 0.74 Diluted $ 0.66 $ 0.72
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table summarizes the securities that were antidilutive or out-of-the-money, and therefore, were not included in the computations of diluted income per common share: For the Years Ended December 31, 2021 December 31, 2020 Out-of-the-money warrants (1) 2,981,473 4,576,799 Service-based RSUs 54 7,471 Performance and market-based RSUs (2) 14,164 276 Employee stock purchase plan — 3,217 Total 2,995,691 4,587,763 (1) On July 20, 2021, 2,140,214 Public Warrants, 99,000 Private Warrants, and 935,068 Additional Merger Warrants expired by their terms. Through their date of expiration, the Company calculated, on a security-by-security basis, the average market price for the portion of the period in which these securities were outstanding and concluded that these warrants were considered out-of-the-money, and therefore, were not included in the computation of diluted income per common share. (2) For the years ended December 31, 2021 and 2020, certain PRSU and MRSU awards (each defined in Note 16) were not included in the computation of diluted income per common share because the performance and market conditions were not satisfied during the periods and would not be satisfied if the reporting date was at the end of the contingency period.

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Outstanding Warrants	The following table summarizes the underlying shares of common stock with respect to outstanding warrants: December 31, 2021 December 31, 2020 Public Warrants (1)(6) — 2,300,000 Private Warrants (2)(6) — 99,000 $15 Exercise Price Warrants (3)(6) 600,000 600,000 Merger Warrants (4)(7) 629,643 631,119 Additional Merger Warrants (5)(7) — 946,680 Total 1,229,643 4,576,799 (1) Exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Public Warrants”). (2) Exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Private Warrants”). (3) Exercisable for one share of common stock at an exercise price of $15.00 per share (“$15 Exercise Price Sponsor Warrants”). (4) Exercisable for one share of common stock at an exercise price of $12.50 per share (“Merger Warrants”). (5) Exercisable for one share of common stock at an exercise price of $11.50 per share (“Additional Merger Warrants”). (6) Issued under a warrant agreement dated July 15, 2014, between Continental Stock Transfer and Trust Company, as warrant agent, and the Company. (7) Issued to the sellers of LHLLC.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Income Tax Provision	The income tax provision from income taxes for December 31, 2021 and 2020 consisted of the following: For the Years Ended (in thousands) December 31, 2021 December 31, 2020 Current tax provision U.S. Federal $ 812 $ 1,274 State and local 194 1,209 Total current tax provision 1,006 2,483 Deferred tax provision (benefit) U.S. Federal 1,127 (643) State and local 630 (658) Total deferred tax provision (benefit) 1,757 (1,301) Income tax provision $ 2,763 $ 1,182
Schedule of Deferred Tax Assets (Liabilities)	The components of deferred tax assets (liabilities) were as follows: As of As of December 31, (in thousands) 2021 2020 Deferred tax assets: Accrued expenses $ 1,328 $ 2,096 Allowance for doubtful accounts 68 71 Intangibles 524 784 Goodwill 3,304 3,746 Startup costs 79 91 Stock-based compensation 881 501 Lease liabilities 5,547 5,268 Accrued bonuses and commissions 1,810 2,030 Warrant — 535 Total deferred tax assets 13,541 15,122 Deferred tax liabilities: Fixed assets (3,775) (3,813) Right-of-use assets (5,231) (4,975) Debt discounts — (155) Percentage of completion (205) (92) Total deferred tax liabilities (9,211) (9,035) Net deferred tax asset $ 4,330 $ 6,087
Schedule of Reconciliation of Federal Statutory Income Tax Rate to Company's Effective Tax Rate	A reconciliation of the federal statutory income tax rate to the Company’s effective tax rate is as follows: For the Years Ended December 31, 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % State income taxes, net of federal tax effect 7.0 % 6.3 % Change in uncertain tax benefits — % (0.6) % Stock based compensation – restricted stock (1.1) % 2.0 % Return to provision adjustment 1.2 % (0.7) % Permanent differences 1.9 % 1.1 % Tax credits (0.8) % (2.7) % CARES Act carryback — % (9.4) % Effective tax rate 29.2 % 17.0 %

Operating Segments (Tables)

Operating Segments (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Information	Segment information for the periods presented is as follows: For the Years Ended December 31, (in thousands) 2021 2020 Statement of Operations Data: Revenue: GCR $ 350,015 $ 440,979 ODR 140,336 127,230 Total revenue 490,351 568,209 Gross profit: GCR 45,409 45,115 ODR 40,501 36,271 Total gross profit 85,910 81,386 Selling, general and administrative: GCR 37,558 37,708 ODR 31,277 24,825 Corporate 2,601 1,068 Total selling, general and administrative 71,436 63,601 Amortization of intangibles 484 630 Operating income $ 13,990 $ 17,155 Less Unallocated amounts: Interest expense, net (2,568) (8,627) Loss on debt extinguishment (1,961) — Gain (loss) on change in fair value of warrant liability 14 (1,634) Gain on sale of property and equipment 2 95 Total unallocated amounts (4,513) (10,166) Total consolidated income before income taxes $ 9,477 $ 6,989 Other Data: Depreciation and amortization: GCR $ 4,085 $ 4,187 ODR 1,379 1,354 Corporate 484 630 Total other data $ 5,948 $ 6,171

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Components of Self-insurance	The components of the self-insurance liability as of December 31, 2021 and 2020 are as follows: (in thousands) December 31, 2021 December 31, 2020 Current liability — workers' compensation and general liability $ 184 $ 197 Current liability — medical and dental 456 764 Non-current liability 451 890 Total liability $ 1,091 $ 1,851 Restricted cash $ 113 $ 113

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Schedule of Supplemental Balance Sheets Information	The following table summarizes the lease amounts included in the Company’s consolidated balance sheets as of December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Balance Sheets December 31, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 20,119 $ 18,751 Finance Property and equipment, net (b) 4,916 6,242 Total lease assets $ 25,035 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,366 $ 3,929 Finance Current portion of long-term debt 2,451 2,536 Noncurrent Operating Long-term operating lease liabilities 16,576 15,459 Finance Long-term debt 2,681 3,923 Total lease liabilities $ 26,074 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.9 million and $11.9 million at December 31, 2021 and 2020, respectively. (b) Finance lease assets are recorded net of accumulated amortization of $5.9 million and $5.3 million at December 31, 2021 and 2020, respectively.
Schedule of Lease Costs, Terms and Discount Rates	The following table summarizes the lease costs included in the Company’s consolidated statements of operations for the years ended December 31, 2021 and 2020: (in thousands) Classification on the Consolidated Statements of Operations December 31, 2021 December 31, 2020 Operating lease cost Cost of revenue (a) $ 2,901 $ 3,527 Operating lease cost Selling, general and administrative (a) 2,223 1,483 Finance lease cost: Amortization Cost of revenue (b) 2,622 2,711 Interest Interest expense, net (b) 305 363 Total lease cost $ 8,051 $ 8,084 (a) Operating lease costs recorded in cost of sales includes $0.5 million and $0.7 million of variable lease costs for both the years ended December 31, 2021 and 2020, respectively. In addition, $0.4 million and $0.3 million of variable lease costs are included in selling, general and administrative expenses for the years ended December 31, 2021 and 2020, respectively. These variable costs consist of our proportionate share of operating expenses, real estate taxes, and utilities. (b) Finance lease costs recorded in cost of revenue includes $2.8 million and $2.4 million of variable leases costs for the years ended December 31, 2021 and 2020, respectively. These variable lease costs consist of fuel, maintenance, and sales tax charges. No variable lease costs for finance leases were recorded in selling, general and administrative expenses for the years ended December 31, 2021 or 2020. The following is a summary of the lease terms and discount rates as of: December 31, 2021 December 31, 2020 Weighted average lease term (in years) Operating 7.10 5.48 Finance 2.51 2.78 Weighted average discount rate Operating 4.68 % 4.83 % Finance 5.27 % 5.50 %
Schedule of Future Minimum Commitment for Finance leases	Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of the year ended December 31, 2021 were as follows (in thousands): Operating Leases Year ending December 31: Finance Non-Related Party Related Party (1) Sublease Receipts (2) Total Operating 2022 $ 2,658 $ 4,800 $ 450 $ (657) $ 4,593 2023 1,662 3,516 450 (677) 3,289 2024 851 2,917 450 (697) 2,670 2025 289 2,409 450 (718) 2,141 2026 12 2,010 450 (740) 1,720 Thereafter — 2,033 4,815 (250) 6,598 Total minimum lease payments $ 5,472 $ 17,685 $ 7,065 $ (3,739) $ 21,011 Amounts representing interest (340) Present value of net minimum lease payments $ 5,132 (1) Associated with the aforementioned related party lease entered into with a former member of JMLLC. (2) Associated with the aforementioned third party sublease.
Schedule of Future Minimum Commitment for Operating Leases	Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of the year ended December 31, 2021 were as follows (in thousands): Operating Leases Year ending December 31: Finance Non-Related Party Related Party (1) Sublease Receipts (2) Total Operating 2022 $ 2,658 $ 4,800 $ 450 $ (657) $ 4,593 2023 1,662 3,516 450 (677) 3,289 2024 851 2,917 450 (697) 2,670 2025 289 2,409 450 (718) 2,141 2026 12 2,010 450 (740) 1,720 Thereafter — 2,033 4,815 (250) 6,598 Total minimum lease payments $ 5,472 $ 17,685 $ 7,065 $ (3,739) $ 21,011 Amounts representing interest (340) Present value of net minimum lease payments $ 5,132 (1) Associated with the aforementioned related party lease entered into with a former member of JMLLC. (2) Associated with the aforementioned third party sublease.
Schedule of Supplemental Cash Flow Information	The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Year Ended December 31, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 4,938 $ 5,164 Operating cash flows from finance leases 305 363 Financing cash flows from finance leases 2,623 2,664 Right-of-use assets exchanged for lease liabilities Operating leases $ 5,417 $ 1,096 Finance leases 1,296 2,624 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 219 $ 621 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — $ (86)

Multiemployer Pension Plans (Ta

Multiemployer Pension Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Schedule of Multiemployer Plans	The following table presents the MEPPs in which the Company participates. Additionally, this table also lists the PPA Zone Status for MEPPs as the critical status (red zone-less than 65% funded), the endangered status (yellow-less than 80% funded), the seriously endangered status (orange-less than 80% funded and projects a credit balance deficit within seven years) or neither critical or endangered status (green-greater than 80% funded). The zone status represents the most recent available information for the respective MEPP, which is 2020 for the 2021 year. These dates may not correspond with the Company’s calendar year contributions. The zone status is based on information received from the MEPPs and is certified by the MEPPs’ actuaries. The “FIP/RP Status” column indicates MEPPs for which a financial improvement plan (FIP) or rehabilitation plan (RP) has been adopted or implemented. Pension Fund EIN/Pension PPA Zone Status FIP/RP Status Contributions (in Contributions Surcharge Expiration date 2021 2020 2021 2020 Heating, Piping and Refrigeration Pension Fund 52-1058013 / 001 Green Green N/A $ 851 $ 1,045 No No Jul-22 Plumbers Local No 98 Defined Benefit Pension Fund 38-3031916 / 001 Yellow Yellow Implemented 1,386 1,658 Yes No May-25 United Association National Pension Fund (2) 52-6152779 / 001 Yellow Yellow Implemented 700 947 No No Ranging from May-22 - Aug-26 Pipefitters Local 636 Defined Benefit Pension Fund 38-3009873 / 001 Yellow Yellow Implemented 1,437 1,206 No No May-22 Sheet Metal Workers' Pension Plan of Southern California, Arizona and Nevada 95-6052257 / 001 Yellow Yellow Implemented 297 1,322 No No Jun-24 Sheet Metal Workers' National Pension Fund 52-6112463 / 001 Yellow Yellow Implemented 701 1,144 No No Ranging from May-23 – Apr-26 Sheet Metal Workers Local Union No. 80 Pension Fund 38-6105633 / 001 Green Yellow Implemented 1,571 1,383 Yes No May-26 Sheet Metal Workers Local 98 Pension Fund 31-6171213 / 001 Green Green Implemented 1,003 945 Yes No May 23 Steamfitters Local Union No. 420 Pension Fund 23-2004424 / 001 Red Red Implemented 526 591 No No Apr-23 Pipefitters Union Local No. 537 Pension Fund 51-6030859 / 001 Green Green N/A 1,805 1,337 No No Aug-25 Plumbers & Pipefitters Local No 189 Pension Plan 31-0894807 / 001 Green Green N/A 489 598 Yes No May-22 Plumbers & Pipefitters of Local Union No. 333 Pension Fund 38-3545518 / 005 Green Green Implemented 1,694 1,329 Yes No May-22 Southern California Pipe Trades Retirement Fund 51-6108443 / 001 Green Green N/A 161 662 No No Aug-26 Electrical Workers Local No. 26 Pension Trust Fund 52-6117919 / 001 Green Green N/A 429 348 No No May-24 Plumbers Union Local No. 12 Pension 04-6023174 / 001 Green Green N/A 131 261 No No Aug-25 Sheet Metal Workers Local 7, Zone 1 Pension Plan 38-6234066 / 001 Green Yellow Implemented 293 383 No No Apr-26 Plumbers & Steamfitters Local 577 Pension Plan 31-6134953 /001 Yellow Yellow Implemented 277 208 No No May-23 Plumbers Local Union No. 690 Pension Fund 23-6405018 / 001 Green Green N/A 53 147 No No Apr-24 Laborers District Council Pension and Disability Trust Fund No. 2 52-0749130 / 001 Yellow Yellow Implemented 33 37 No No Oct-21 National Electrical Benefit Fund 53-0181657 / 001 Green Green N/A 1 111 No No May-24 Airconditioning and Refrigeration Industry Retirement Trust Fund 95-6035386 / 001 Green Green N/A 130 144 No No Aug-24 Plumbers and Steamfitters Local 486 Pension Fund 52-6124449 / 001 Green Green N/A 15 40 No No Dec-22 Steamfitters Local #449 Pension Plan 25-6032401 / 001 Green (1) Green N/A 68 109 No No May-23 United Association Local Union No. 322 Pension Plan 21-6016638 / 001 Red Red Implemented 24 18 No Yes Apr-24 Sheet Metal Workers Local 224 Pension Fund 31-6171353 / 001 Yellow (1) Yellow Implemented 21 20 No No May-24 Plumbers Local 27 Pension Fund 25-6034928 / 001 Green (1) Green N/A — 18 No No May-23 Plumbers and Pipefitters Local Union No. 43 Pension Fund 62-6101288 / 001 Green Green Implemented 95 — Yes No June-24 All other plans (15 and 11 as of December 31, 2021 and 2020, respectively) 127 98 Total Contributions $ 14,318 $ 16,109 (1) Funding status based off of the prior year funding notice as the current year’s funding notice was not available prior to the filing of this Annual Report on Form 10-K. (2) Formerly the Plumbers and Pipefitters National Pension Fund.

Management Incentive Plans (Tab

Management Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2021
RSUs
Schedule of Share-based Awards Activity	The following table summarizes our service-based RSU activity: Awards Weighted-Average Unvested at January 1, 2020 328,575 $ 7.83 Granted 178,633 2.64 Vested (211,300) 8.12 Forfeited (10,109) 6.80 Unvested at December 31, 2020 285,799 $ 6.32 Granted 127,407 11.99 Vested (144,784) 7.35 Forfeited (2,333) 8.27 Unvested at December 31, 2021 266,089 $ 8.45
PRSUs
Schedule of Share-based Awards Activity	The following table summarizes our PRSU activity: Awards Weighted-Average Unvested at January 1, 2020 62,307 $ 12.62 Granted 96,500 3.67 Vested — — Forfeited (59,307) 12.95 Unvested at December 31, 2020 99,500 $ 4.23 Granted 185,367 12.26 Vested — — Forfeited (4,167) 8.92 Unvested at December 31, 2021 280,700 $ 9.46
MRSUs
Schedule of Share-based Awards Activity	The following table summarizes our MRSU activity for the fiscal years ended December 31, 2021 and 2020: Awards Weighted-Average Unvested at January 1, 2020 125,000 $ 6.58 Granted — — Vested — — Forfeited (22,500) 6.58 Unvested at December 31, 2020 102,500 $ 8.26 Granted — — Vested — — Forfeited — — Unvested at December 31, 2021 102,500 $ 8.26
Schedule of Assumptions Used to Value MRSUs	The table below sets forth the assumptions used within the initial Monte Carlo simulation model to value the MRSU awards: Risk-free interest rate 1.56 % Dividend yield 0 % Remaining performance period (years) 3.92 Expected volatility 28.54 % Estimated grant date fair value (per share) $ 6.58 Derived service period (years) 1.96

Business and Organization (Deta

Business and Organization (Details)	12 Months Ended
	Dec. 31, 2021approachsegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | segment	2
Number customer base approaches | approach	2
Service period	2 years

Significant Accounting Polici_4

Significant Accounting Policies - Narrative (Details) - USD ($)	Dec. 02, 2021	Feb. 24, 2021	Dec. 31, 2021	Dec. 31, 2020	Apr. 12, 2019
Cash and Cash Equivalents [Line Items]
FDIC coverage limit			$ 250,000
Cash balance in excess of FDIC limit			14,200,000	$ 41,900,000
Allowance for doubtful accounts			263,000	266,000
Depreciation			5,500,000	5,500,000
(Income) expense recorded on change in fair value of warrant liability			(14,000)	1,634,000
Jake Marshall Transaction
Cash and Cash Equivalents [Line Items]
Intangible assets acquired	$ 5,700,000
Jake Marshall Transaction | Fair Value, Inputs, Level 3 | Earnout Payments
Cash and Cash Equivalents [Line Items]
Fair value of earnout payments			$ 3,100,000
Minimum
Cash and Cash Equivalents [Line Items]
Term of service contract			6 months
Minimum | Buildings and leasehold improvements
Cash and Cash Equivalents [Line Items]
Property, plant and equipment, useful life			5 years
Minimum | Machinery and equipment
Cash and Cash Equivalents [Line Items]
Property, plant and equipment, useful life			3 years
Maximum
Cash and Cash Equivalents [Line Items]
Term of service contract			2 years
Maximum | Buildings and leasehold improvements
Cash and Cash Equivalents [Line Items]
Property, plant and equipment, useful life			40 years
Maximum | Machinery and equipment
Cash and Cash Equivalents [Line Items]
Property, plant and equipment, useful life			10 years
A&R Wintrust Term Loan | Fair Value, Inputs, Level 3
Cash and Cash Equivalents [Line Items]
Fair value of debt			$ 34,900,000
2019 Refinancing Agreement
Cash and Cash Equivalents [Line Items]
Warrants liability		$ 2,000,000	0	2,000,000	$ 900,000
(Income) expense recorded on change in fair value of warrant liability		$ (100,000)		$ 1,600,000
Revolving Credit Facility | A&R Wintrust Revolving Loan
Cash and Cash Equivalents [Line Items]
Line of credit facility, fair value of amount outstanding			$ 0

Significant Accounting Polici_5

Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 14,476	$ 42,147
Restricted cash	113	113
Total cash, cash equivalents and restricted cash	$ 14,589	$ 42,260	$ 8,457

Significant Accounting Polici_6

Significant Accounting Policies - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 02, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Finance leases - vehicles	$ 10,771		$ 11,505
Gross property and equipment	46,492		41,303
Less: Accumulated amortization on finance leases	(5,855)		(5,263)
Less:  Accumulated depreciation	(19,016)		(16,340)
Property and equipment, net of accumulated depreciation and amortization	21,621		19,700
Jake Marshall Transaction
Property, Plant and Equipment [Line Items]
Net property and equipment acquired	5,600	$ 5,762
Land and improvements
Property, Plant and Equipment [Line Items]
Gross property and equipment	400		400
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property and equipment	10,721		7,751
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 24,600		$ 21,647

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) $ in Thousands	Dec. 02, 2021USD ($)payment	Dec. 31, 2021USD ($)covenant	Dec. 31, 2021USD ($)covenant	Dec. 31, 2020USD ($)
Business Acquisition [Line Items]
Goodwill associated with acquisition			$ 5,241
Amortization of intangibles			484	$ 630
Estimated annual amortization expense year one		$ 1,567	1,567
Estimated annual amortization expense year two		1,211	1,211
Estimated annual amortization expense year three		867	867
Estimated annual amortization expense year four		830	830
Estimated annual amortization expense year five		800	800
2022 Earnout Period
Business Acquisition [Line Items]
Number of earnout tranches | payment	2
2023 Earnout Period
Business Acquisition [Line Items]
Number of earnout tranches | payment	2
ODR
Business Acquisition [Line Items]
Goodwill associated with acquisition			5,241
Jake Marshall Transaction
Business Acquisition [Line Items]
Closing purchase price	$ 21,313
Amount of consideration paid held in escrow for indemnification purposes	1,000
Earnout payments	6,000
Acquisition-related expenses			600
Amortization of intangibles		100
Estimated annual amortization expense year one		1,300	1,300
Estimated annual amortization expense year two		1,000	1,000
Estimated annual amortization expense year three		700	700
Estimated annual amortization expense year four		700	700
Estimated annual amortization expense year five		700	700
Jake Marshall Transaction | Earnout Payments | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Fair value of earnout payments		$ 3,100	$ 3,100
Jake Marshall Transaction | Earnout Payments | Fair Value, Inputs, Level 3 | Measurement Input, Discount Rate
Business Acquisition [Line Items]
Earnout payments, measurement input | covenant		0.0683	0.0683
Jake Marshall Transaction | 2022 Earnout Period
Business Acquisition [Line Items]
Earnout payments	$ 3,000
Earnout period	13 months
Jake Marshall Transaction | 2022 Earnout Period | Equal or Exceeds
Business Acquisition [Line Items]
Gross profits from acquired companies	$ 10,000
Jake Marshall Transaction | 2022 Earnout Period | Exceeds
Business Acquisition [Line Items]
Gross profits from acquired companies	8,000
Jake Marshall Transaction | 2023 Earnout Period
Business Acquisition [Line Items]
Earnout payments	$ 3,000
Earnout period	13 months
Jake Marshall Transaction | 2023 Earnout Period | Equal or Exceeds
Business Acquisition [Line Items]
Gross profits from acquired companies	$ 10,000
Jake Marshall Transaction | 2023 Earnout Period | Exceeds
Business Acquisition [Line Items]
Gross profits from acquired companies	8,000
Jake Marshall Transaction | ODR
Business Acquisition [Line Items]
Goodwill associated with acquisition	5,200
Goodwill fully deductible for tax purposes	$ 5,200

Acquisitions - Allocation of Pu

Acquisitions - Allocation of Purchase Price of Assets and Liabilities from Jake Marshall Transaction (Details) - USD ($) $ in Thousands	Dec. 02, 2021	Dec. 31, 2021	Dec. 31, 2020
Fair value of liabilities assumed:
Goodwill		$ 11,370	$ 6,129
Jake Marshall Transaction
Consideration:
Cash	$ 21,313
Earnout provision	3,089
Total Consideration	24,402
Fair value of assets acquired:
Cash and cash equivalents	2,336
Accounts receivable	7,165
Contract assets	1,711
Other current assets	164
Property and equipment	5,762	$ 5,600
Intangible assets	5,710
Amount attributable to assets acquired	22,848
Fair value of liabilities assumed:
Accounts payable, including retainage	2,655
Accrued expenses and other current liabilities	570
Contract liabilities	462
Amount attributable to liabilities assumed	3,687
Goodwill	$ 5,241

Acquisitions - Intangible Asset

Acquisitions - Intangible Assets Acquired (Details) - USD ($) $ in Thousands	Dec. 02, 2021	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Gross carrying amount		$ 10,610	$ 5,240
Accumulated amortization		(3,663)	(3,519)
Total		6,947	1,721
Customer relationships
Business Acquisition [Line Items]
Gross carrying amount			4,710
Accumulated amortization			(3,112)
Total			1,598
Customer relationships | ODR
Business Acquisition [Line Items]
Gross carrying amount		4,710
Accumulated amortization		(3,475)
Total		1,235
Backlog
Business Acquisition [Line Items]
Gross carrying amount			4,800
Accumulated amortization			$ (4,800)
Jake Marshall Transaction
Business Acquisition [Line Items]
Gross carrying amount	$ 5,710
Accumulated amortization	(105)
Total	$ 5,605
Weighted Average Useful Life (Years)	6 years 3 months 18 days
Jake Marshall Transaction | Trade name
Business Acquisition [Line Items]
Gross carrying amount	$ 1,150	1,150
Accumulated amortization	(15)	(15)
Total	$ 1,135	1,135
Weighted Average Useful Life (Years)	6 years 2 months 12 days
Jake Marshall Transaction | Customer relationships | GCR
Business Acquisition [Line Items]
Gross carrying amount	$ 570	570
Accumulated amortization	(6)	(6)
Total	$ 564	564
Weighted Average Useful Life (Years)	7 years 1 month 6 days
Jake Marshall Transaction | Customer relationships | ODR
Business Acquisition [Line Items]
Gross carrying amount	$ 3,050	3,050
Accumulated amortization	(34)	(35)
Total	$ 3,016	3,015
Weighted Average Useful Life (Years)	7 years 7 months 6 days
Jake Marshall Transaction | Backlog | GCR
Business Acquisition [Line Items]
Gross carrying amount	$ 260	260
Accumulated amortization	(14)	(14)
Total	$ 246	246
Weighted Average Useful Life (Years)	1 year 7 months 6 days
Jake Marshall Transaction | Backlog | ODR
Business Acquisition [Line Items]
Gross carrying amount	$ 680	680
Accumulated amortization	(36)	(36)
Total	$ 644	$ 644
Weighted Average Useful Life (Years)	1 year 7 months 6 days

Acquisitions - Unaudited Pro Fo

Acquisitions - Unaudited Pro Forma Information (Details) - Jake Marshall Transaction - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Pro forma revenue	$ 523,479	$ 599,013
Pro forma net income	$ 5,392	$ 4,310
Pro forma EPS (basic) ( in dollars per share)	$ 0.54	$ 0.55
Pro forma EPS (diluted) (in dollars per share)	$ 0.53	$ 0.53

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Term of revenue contracts	six months to two years
Percentage completed of certain milestones	10.00%
Net amount of unresolved change orders and claims	$ 38,100	$ 33,600
Total net gross profits write ups (downs)	$ 400	$ (7,900)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	24 months
GCR
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 337,200
GCR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	65.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
GCR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	35.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
ODR
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 81,200
ODR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	52.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
ODR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	5.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Components of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Contract assets
Costs in excess of billings and estimated earnings	$ 47,447	$ 31,894
Retainage receivable	36,416	35,204
Contract assets	83,863	67,098
Change in costs in excess of billings and estimated earnings	15,553
Change in retainage receivable	1,212
Change in total contract assets	16,765
Contract liabilities
Billings in excess of costs and estimated earnings on uncompleted contracts	26,293	46,020
Provisions for losses	419	628
Total contract liabilities	26,712	$ 46,648
Change in billings in excess of costs and estimated earnings	(19,727)
Change in provisions for losses	(209)
Change in total contract liabilities	$ (19,936)

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contracts in Progress (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue earned on uncompleted contracts	$ 758,450	$ 752,564
Less: Billings to date	(737,296)	(766,690)
Net underbilling (overbilling)	21,154	(14,126)
Costs in excess of billings and estimated earnings	47,447	31,894
Billings in excess of costs and estimated earnings	$ (26,293)	$ (46,020)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Revisions in Contract Estimates (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)project	Dec. 31, 2020USD ($)project
Revenue from Contract with Customer [Abstract]
Revision amount of gross profit contract estimates (more than)	$ 250
Disaggregation of Revenue [Line Items]
Gross profit write-up	$ 5,663	$ 1,654
Project count | project	12	3
Gross profit write ups	$ (6,290)	$ (10,379)
Project count | project	9	15
Total gross profit write-downs, net	$ (627)	$ (8,725)
GCR
Disaggregation of Revenue [Line Items]
Gross profit write-up	$ 5,663	$ 1,654
Project count | project	12	3
Gross profit write ups	$ (5,958)	$ (10,379)
Project count | project	8	15
ODR
Disaggregation of Revenue [Line Items]
Gross profit write-up	$ 0	$ 0
Project count | project	0	0
Gross profit write ups	$ (332)	$ 0
Project count | project	1	0

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets		$ 0	$ 0
Amortization of intangibles		$ 484,000	630,000
Trade name
Finite-Lived Intangible Assets [Line Items]
Amount of fair value of intangibles in excess of carrying value	$ 1,000,000
Percentage of fair value of intangibles in excess of carrying amount	0.10
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life		1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life		15 years
ODR
Finite-Lived Intangible Assets [Line Items]
Amount of fair value of reporting unit in excess of carrying amount	$ 33,300,000
Percentage of fair value or reporting unit in excess of carrying amount	169.00%
Goodwill impairment	$ 0		$ 0

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 6,129
Goodwill associated with the Jake Marshall Transaction	5,241
Ending Balance	11,370
GCR
Goodwill [Roll Forward]
Beginning Balance	0
Goodwill associated with the Jake Marshall Transaction	0
Ending Balance	0
ODR
Goodwill [Roll Forward]
Beginning Balance	6,129
Goodwill associated with the Jake Marshall Transaction	5,241
Ending Balance	$ 11,370

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Definite-lived and Indefinite-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 02, 2021	Dec. 31, 2020
Amortized intangible assets:
Gross carrying amount		$ 10,610		$ 5,240
Accumulated amortization		(3,663)		(3,519)
Total		6,947		1,721
Unamortized intangible assets:
Gross carrying amount		9,960		9,960
Total		9,960		9,960
Gross carrying amount		20,570		15,200
Accumulated amortization		(3,663)		(3,519)
Net intangible assets, excluding goodwill		16,907		11,681
Trade name
Unamortized intangible assets:
Gross carrying amount		9,960		9,960
Total		9,960		9,960
Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount			$ 5,710
Accumulated amortization			(105)
Total			5,605
Unamortized intangible assets:
Accumulated amortization			(105)
Customer relationships
Amortized intangible assets:
Gross carrying amount				4,710
Accumulated amortization				(3,112)
Total				1,598
Unamortized intangible assets:
Accumulated amortization				(3,112)
Customer relationships | GCR | Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount		570	570
Accumulated amortization		(6)	(6)
Total		564	564
Unamortized intangible assets:
Accumulated amortization		(6)	(6)
Customer relationships | ODR
Amortized intangible assets:
Gross carrying amount		4,710
Accumulated amortization		(3,475)
Total		1,235
Unamortized intangible assets:
Accumulated amortization		(3,475)
Customer relationships | ODR | Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount		3,050	3,050
Accumulated amortization		(35)	(34)
Total		3,015	3,016
Unamortized intangible assets:
Accumulated amortization		(35)	(34)
Favorable leasehold interests
Amortized intangible assets:
Gross carrying amount		190		530
Accumulated amortization		(82)		(407)
Total		108		123
Unamortized intangible assets:
Accumulated amortization		(82)		(407)
Reduction in gross carrying amount and accumulated amortization of intangibles due to lease termination	$ 300
Backlog
Amortized intangible assets:
Gross carrying amount				4,800
Accumulated amortization				(4,800)
Unamortized intangible assets:
Accumulated amortization				$ (4,800)
Backlog | GCR | Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount		260	260
Accumulated amortization		(14)	(14)
Total		246	246
Unamortized intangible assets:
Accumulated amortization		(14)	(14)
Backlog | ODR | Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount		680	680
Accumulated amortization		(36)	(36)
Total		644	644
Unamortized intangible assets:
Accumulated amortization		(36)	(36)
Trade name | Jake Marshall Transaction
Amortized intangible assets:
Gross carrying amount		1,150	1,150
Accumulated amortization		(15)	(15)
Total		1,135	1,135
Unamortized intangible assets:
Accumulated amortization		$ (15)	$ (15)

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Estimated Remaining Useful Lives of Definite-Lived Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2021
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	7 years 2 months 12 days
Customer relationships | GCR | Jake Marshall Transaction
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	7 years
Customer relationships | ODR
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	9 years
Customer relationships | ODR | Jake Marshall Transaction
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	7 years 6 months
Backlog | GCR | Jake Marshall Transaction
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	1 year 6 months
Backlog | ODR | Jake Marshall Transaction
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	1 year 6 months
Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated Remaining Useful Life (Years)	6 years 1 month 6 days

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 1,567
2023	1,211
2024	867
2025	830
2026	800
2027 and thereafter	1,672
Total	$ 6,947	$ 1,721

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued payroll and related liabilities	$ 8,169	$ 7,975
Accrued bonus and commissions	7,352	7,652
Accrued insurance liabilities	719	1,008
Accrued job costs	3,772	3,131
Assurance-type warranty liabilities	3,310	4,056
Other accrued liabilities	1,122	925
Total	$ 24,444	$ 24,747

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Narrative (Details) $ in Millions	Dec. 31, 2021USD ($)
Payables and Accruals [Abstract]
Liability for FICA withholding under CARES Act provisions	$ 3.2

Accrued Expenses and Other Cu_5

Accrued Expenses and Other Current Liabilities- Reconciliation of Assurance-type Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at the beginning of the period	$ 4,056	$ 2,886
Accruals for warranties issued	432	687
Accruals related to pre-existing warranties (including changes in estimates)	401	1,856
Settlements made	(1,579)	(1,373)
Balance at the end of the period	$ 3,310	$ 4,056

Debt - Long-term Debt (Details)

Debt - Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.55% to 6.45% through 2026	$ 5,132	$ 6,459
Total debt	40,013	45,459
Less - Current portion of long-term debt	(9,879)	(6,536)
Less - Unamortized discount and debt issuance costs	(318)	(2,410)
Long-term debt	$ 29,816	36,513
Minimum
Finance leases, interest rate	4.55%
Maximum
Finance leases, interest rate	6.45%
2019 Refinancing Term Loan – term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022
Long-term debt		39,000
Term Loan | A&R Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in December 2021) plus interest through February 2026
Long-term debt	$ 34,881	0
Term Loan | 2019 Refinancing Term Loan – term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022
Long-term debt	0	39,000
Revolving Credit Facility | A&R Wintrust Revolving Loan
Long-term debt	$ 0	$ 0

Debt - Maturities of Long-Term

Debt - Maturities of Long-Term Debt and Finance Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
2022	$ 9,879
2023	8,997
2024	8,247
2025	7,710
2026	5,180
Total debt	$ 40,013	$ 45,459

Debt - 2019 Refinancing Agreeme

Debt - 2019 Refinancing Agreement - 2019 Term Loans (Details)

Apr. 01, 2021

Feb. 24, 2021USD ($)

Jan. 01, 2020

Oct. 01, 2019USD ($)

Apr. 12, 2019USD ($)covenant

Jul. 31, 2021

Mar. 31, 2020

Nov. 30, 2019USD ($)

Jun. 30, 2019

Feb. 24, 2021USD ($)

Sep. 30, 2020USD ($)

Dec. 31, 2021USD ($)

Dec. 31, 2020USD ($)

Aug. 31, 2020

Debt Instrument [Line Items]

Loss on debt extinguishment

$ 1,961,000

$ 0

(Income) expense recorded on change in fair value of warrant liability

$ (14,000)

$ 1,634,000

2019 Refinancing Agreement

Debt Instrument [Line Items]

Debt issued

$ 40,000,000

Debt instrument, interest rate, effective percentage

13.00%

13.00%

13.00%

Amortization of debt issuance costs

$ 100,000

$ 1,000,000

$ 1,400,000

Line of credit facility, unused capacity, commitment fee percentage

2.00%

Make-whole premium prepayment period

19 months

Make-whole provision applicable to interest period

18 months

Number of financial covenants | covenant

2

Leverage ratio

200.00%

330.00%

425.00%

425.00%

461.00%

Leverage ratio minimum requirement

4

Debt instrument, interest rate, increase (decrease)

1.00%

(Income) expense recorded on change in fair value of warrant liability

$ (100,000)

1,600,000

2019 Refinancing Amendment Number One and Waiver

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 15,000,000

Line of credit facility, unused capacity, commitment fee percentage

50.10%

Leverage ratio

200.00%

330.00%

425.00%

Debt instrument, interest rate, increase (decrease)

3.00%

Debt instrument, percentage of customer accounts required to approve amendment

75.00%

Debt instrument, non refundable waiver fee

$ 400,000

Debt instrument, non refundable amendment fee

1,000,000

2019 Refinancing Term Loan

Debt Instrument [Line Items]

Collateral coverage amount

37,900,000

Debt outstanding

39,000,000

Debt outstanding balance in excess of collateral coverage amount

$ 1,100,000

Loss on debt extinguishment

$ 2,000,000

Write-off of unamortized discount and financing costs

2,600,000

(Income) expense recorded on change in fair value of warrant liability

2,000,000

Prepayment penalty and other extinguishment costs

$ 1,400,000

Minimum | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Leverage ratio

200.00%

Minimum | 2019 Refinancing Amendment Number One and Waiver

Debt Instrument [Line Items]

Debt instrument, liquidity of loan parties

$ 10,000,000

Maximum | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Leverage ratio

400.00%

LIBOR | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Basis spread over variable rate

11.00%

LIBOR | Minimum | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Basis spread over variable rate

2.00%

Base Rate | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Basis spread over variable rate

10.00%

Base Rate | Minimum | 2019 Refinancing Agreement

Debt Instrument [Line Items]

Basis spread over variable rate

3.00%

Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 25,000,000

Debt - 2019 Refinancing Agree_2

Debt - 2019 Refinancing Agreement - CB Warrants (Details) - USD ($)	Apr. 12, 2019	Feb. 24, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2019
Debt Instrument [Line Items]
Percentage of number of shares	2.00%
2019 Refinancing Term Loan embedded derivative
Debt Instrument [Line Items]
Warrant exercise price (in usd per share)	$ 7.63
Number of warrants per each share of common stock (in shares)	263,314	0
Debt outstanding	$ 0
2019 Refinancing Agreement
Debt Instrument [Line Items]
Warrants term	5 years
Warrants outstanding	$ 900,000	$ 2,000,000		$ 2,000,000	$ 0
Derivative liability						$ 400,000
Debt instrument, unamortized discount						1,300,000
Debt issuance costs, net						3,900,000
Interest expense, debt		100,000		500,000
Amortization of debt issuance costs		$ 100,000	$ 1,000,000	$ 1,400,000
Refinancing Agreement 2019 First Amendment
Debt Instrument [Line Items]
Debt issuance costs, net						$ 1,400,000

Debt - 2019 ABL Agreement (Deta

Debt - 2019 ABL Agreement (Details) - USD ($)	Apr. 01, 2021	Oct. 01, 2019	Apr. 12, 2019	Jul. 31, 2021	Mar. 31, 2020	Jun. 30, 2019	Feb. 24, 2021	Dec. 31, 2021	Dec. 31, 2020	Nov. 30, 2019
2019 ABL Credit Agreement
Debt Instrument [Line Items]
Basis spread over variable rate			3.00%
Debt instrument, interest rate, effective percentage							5.25%		5.25%
Leverage ratio	200.00%	330.00%		1.75%	425.00%	4.00%
Letters of credit									$ 3,400,000
Debt issuance costs, net									900,000
Amortization of debt issuance costs							$ 100,000		$ 300,000
2019 ABL Credit Amendment Number One and Waiver
Debt Instrument [Line Items]
Leverage ratio	200.00%	330.00%			425.00%
Lender's approval for acquisition, percentage								50.10%
Debt instrument, non refundable waiver fee								$ 7,500
Minimum | 2019 ABL Credit Agreement
Debt Instrument [Line Items]
Basis spread over variable rate			2.00%
Debt instrument, interest rate, stated percentage			3.00%
Line of credit facility, unused capacity, commitment fee percentage			0.25%
Minimum | 2019 ABL Credit Amendment Number One and Waiver
Debt Instrument [Line Items]
Debt instrument, liquidity of loan parties										$ 10,000,000
Maximum | 2019 ABL Credit Agreement
Debt Instrument [Line Items]
Basis spread over variable rate			2.50%
Debt instrument, interest rate, stated percentage			3.50%
Line of credit facility, unused capacity, commitment fee percentage			0.375%
LIBOR | 2019 ABL Credit Agreement
Debt Instrument [Line Items]
Basis spread over variable rate			2.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 25,000,000
Revolving Credit Facility | 2019 ABL Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			15,000,000
Line of credit facility, current borrowing capacity			14,000,000
Line of credit facility reserved borrowing capacity			$ 1,000,000

Debt - Wintrust Term and Revolv

Debt - Wintrust Term and Revolving Loans (Details)	Dec. 02, 2021USD ($)covenant	Feb. 24, 2021USD ($)	Dec. 31, 2021USD ($)	Apr. 12, 2019USD ($)
Wintrust Loans
Debt Instrument [Line Items]
Letters of credit			$ 3,400,000
Wintrust Term Loan
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage			4.25%
Wintrust Revolving Loan
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage			3.75%
A&R Wintrust Loans
Debt Instrument [Line Items]
Number of financial covenants | covenant	3
Leverage ratio	200.00%
Coverage ratio	1.20
Aggregate amount of unfinanced capital expenditures during any fiscal year	$ 0
Limit annual percentage of unfinanced capital expenditures	50.00%
A&R Wintrust Loans | Maximum
Debt Instrument [Line Items]
Aggregate amount of unfinanced capital expenditures during any fiscal year	$ 4,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Sublimit for issuance of letters of credit				$ 25,000,000
Term Loan | Wintrust Term Loan
Debt Instrument [Line Items]
Debt issued		$ 30,000,000
Debt installment payments		$ 500,000
Term Loan | A&R Wintrust Term Loan
Debt Instrument [Line Items]
Debt installment payments	600,000
Term Loan | A&R Wintrust Term Loan | Jake Marshall Transaction
Debt Instrument [Line Items]
Debt issued	35,500,000
Term Loan | Revolving Credit Facility | A&R Wintrust Revolving Loan | Jake Marshall Transaction
Debt Instrument [Line Items]
Sublimit for issuance of letters of credit	25,000,000
Term Loan | Sublimit for Letters of Credit | A&R Wintrust Revolving Loan | Jake Marshall Transaction
Debt Instrument [Line Items]
Sublimit for issuance of letters of credit	$ 5,000,000
Line of Credit | A&R Wintrust Term Loan | Base Rate
Debt Instrument [Line Items]
Basis spread over variable rate	1.00%
Variable rate step-down adjustment	0.0075
Line of Credit | A&R Wintrust Term Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate	3.00%
Line of Credit | A&R Wintrust Term Loan | SOFR
Debt Instrument [Line Items]
Variable rate step-down adjustment	0.0050
Line of Credit | A&R Wintrust Term Loan | SOFR | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate	0.15%
Line of Credit | A&R Wintrust Term Loan | SOFR | One month
Debt Instrument [Line Items]
Basis spread over variable rate	4.10%
Line of Credit | A&R Wintrust Term Loan | SOFR | Three months
Debt Instrument [Line Items]
Basis spread over variable rate	4.26%
Line of Credit | A&R Wintrust Term Loan | SOFR | Six months
Debt Instrument [Line Items]
Basis spread over variable rate	4.42%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR
Debt Instrument [Line Items]
Variable rate step-down adjustment		0.0050
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread over variable rate		4.00%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate		0.25%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate
Debt Instrument [Line Items]
Variable rate step-down adjustment		0.0075
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread over variable rate		1.00%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate		3.00%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan
Debt Instrument [Line Items]
Sublimit for issuance of letters of credit		$ 25,000,000
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread over variable rate		3.50%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate		0.25%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate
Debt Instrument [Line Items]
Variable rate step-down adjustment		0.0050
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread over variable rate		0.50%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate		3.00%
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | Base Rate
Debt Instrument [Line Items]
Basis spread over variable rate	0.50%
Variable rate step-down adjustment	0.0050
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate	3.00%
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | SOFR | Minimum
Debt Instrument [Line Items]
Basis spread over variable rate	0.15%
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | SOFR | One month
Debt Instrument [Line Items]
Basis spread over variable rate	3.60%
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | SOFR | Three months
Debt Instrument [Line Items]
Basis spread over variable rate	3.76%
Line of Credit | Revolving Credit Facility | A&R Wintrust Revolving Loan | SOFR | Six months
Debt Instrument [Line Items]
Basis spread over variable rate	3.92%
Line of Credit | Sublimit for Letters of Credit | Wintrust Revolving Loan
Debt Instrument [Line Items]
Sublimit for issuance of letters of credit		$ 5,000,000

Debt - Applicable Margin and Co

Debt - Applicable Margin and Commitment Fees Payable (Details)	12 Months Ended
	Dec. 31, 2021
Level I | A&R Wintrust Term Loan | Prime Rate
Debt Instrument [Line Items]
Additional Margin for Loans	1.00%
Level I | A&R Wintrust Revolving Loan | Prime Rate
Debt Instrument [Line Items]
Additional Margin for Loans	0.50%
Level I | A&R Wintrust Loans
Debt Instrument [Line Items]
Senior Leverage Ratio	100.00%
Applicable Margin for Commitment Fee	0.25%
Level II | A&R Wintrust Term Loan | Prime Rate
Debt Instrument [Line Items]
Additional Margin for Loans	0.25%
Level II | A&R Wintrust Revolving Loan | Prime Rate
Debt Instrument [Line Items]
Additional Margin for Loans	0.00%
Level II | A&R Wintrust Loans
Debt Instrument [Line Items]
Senior Leverage Ratio	100.00%
Applicable Margin for Commitment Fee	0.25%

Earnings per Share - Schedule o

Earnings per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
EPS numerator:
Net income (loss)	$ 6,714	$ 5,807
EPS denominator:
Weighted average shares outstanding – basic (in shares)	10,013,117	7,865,089
Weighted average shares outstanding – diluted (in shares)	10,231,637	8,065,464
Earnings Per Share, Basic [Abstract]
Basic (in usd per share)	$ 0.67	$ 0.74
Diluted (in usd per share)	$ 0.66	$ 0.72
Restricted Stock Units
EPS denominator:
Incremental shares attributable to share-based payments (in shares)	215,000	191,000
Employee Stock
EPS denominator:
Incremental shares attributable to share-based payments (in shares)	4,000	9,000

Earnings per Share - Schedule_2

Earnings per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jul. 20, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,995,691	4,587,763
Public Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants expired (in shares)			2,140,214
Private Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants expired (in shares)			99,000
Additional Merger Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants expired (in shares)			935,068
Out-of-the money warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,981,473	4,576,799
Service-based RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	54	7,471
Performance and market-based RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	14,164	276
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	0	3,217

Equity - Narrative (Details)

Equity - Narrative (Details) - USD ($)	Mar. 09, 2021	Feb. 18, 2021	Feb. 12, 2021	May 24, 2020	Jan. 01, 2020	Apr. 29, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 02, 2021
Class of Stock [Line Items]
Common stock, shares authorized (in shares)							100,000,000	100,000,000
Common stock, par or stated value per share (in usd per share)							$ 0.0001	$ 0.0001
Offering
Class of Stock [Line Items]
Number of shares sold (in shares)			1,783,500
Stock sale price (in usd per share)			$ 12
Proceeds from sale of shares, net of underwriters discounts and commissions			$ 19,800,000
Over-Allotment
Class of Stock [Line Items]
Number of shares sold (in shares)			267,525
Stock sale price (in usd per share)			$ 11.28
Period to purchase additional shares			30 days
Proceeds from sale of shares, net of underwriters discounts and commissions		$ 3,000,000
Omnibus Incentive Plan
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance (in shares)									800,000
2019 Amended and Restated Omnibus Incentive Plan
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance (in shares)						1,150,000
Increase in number of shares that may be issued (in shares)						350,000
2020 Amended and Restated Omnibus Incentive Plan
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance (in shares)				1,650,000
Increase in number of shares that may be issued (in shares)				500,000
2021 Amended and Restated Omnibus Incentive Plan
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance (in shares)	2,250,000
Increase in number of shares that may be issued (in shares)	600,000
ESPP | Employee Stock
Class of Stock [Line Items]
Purchase price of common stock, percent of fair market value					85.00%
Maximum contribution percentage					10.00%
Maximum contribution amount					$ 5,000
Offering period					6 months
Discount percentage from market price, beginning of purchase period					15.00%
Vesting period					6 months
Number of shares authorized to be issued (in shares)					500,000
Number of stock issued (in shares)							25,068	30,825
Shares available for future grants (in shares)							444,107
$15 Exercise Price Sponsor Warrants
Class of Stock [Line Items]
Warrant exercise price (in usd per share)							$ 15
Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)							1,000,000	1,000,000
Preferred stock, par value (in usd per share)							$ 0.0001	$ 0.0001

Equity - Outstanding Warrants (

Equity - Outstanding Warrants (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Warrants outstanding (in shares)	1,229,643	4,576,799
Public Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	0	2,300,000
Number of warrants per each share of common stock (in shares)	0.50	0.50
Class of warrant or right, rights for half share (usd per share)	$ 5.75	$ 5.75
Warrant exercise price (in usd per share)	$ 11.50	$ 11.50
Private Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	0	99,000
Number of warrants per each share of common stock (in shares)	0.50	0.50
Class of warrant or right, rights for half share (usd per share)	$ 5.75	$ 5.75
Warrant exercise price (in usd per share)	$ 11.50	$ 11.50
$15 Exercise Price Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	600,000	600,000
Number of warrants per each share of common stock (in shares)	1	1
Warrant exercise price (in usd per share)	$ 15	$ 15
Merger Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	629,643	631,119
Number of warrants per each share of common stock (in shares)	1	1
Warrant exercise price (in usd per share)	$ 12.50	$ 12.50
Additional Merger Warrants
Class of Stock [Line Items]
Warrants outstanding (in shares)	0	946,680
Number of warrants per each share of common stock (in shares)	1	1
Warrant exercise price (in usd per share)	$ 11.50	$ 11.50

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Valuation allowance against deferred tax assets	$ 0	$ 0
Unrecognized tax benefits	0	0
COVID-19
Operating Loss Carryforwards [Line Items]
Total refundable carryback net operating losses under CARES Act		1,600,000
Proceeds from refundable carryback net operating losses under CARES Act	1,600,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carry forwards	$ 0	$ 0

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Current tax provision
U.S. Federal	$ 812	$ 1,274
State and local	194	1,209
Total current tax provision	1,006	2,483
Deferred tax provision (benefit)
U.S. Federal	1,127	(643)
State and local	630	(658)
Total deferred tax provision (benefit)	1,757	(1,301)
Income tax provision	$ 2,763	$ 1,182

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Accrued expenses	$ 1,328	$ 2,096
Allowance for doubtful accounts	68	71
Intangibles	524	784
Goodwill	3,304	3,746
Startup costs	79	91
Stock-based compensation	881	501
Lease liabilities	5,547	5,268
Accrued bonuses and commissions	1,810	2,030
Warrant	0	535
Total deferred tax assets	13,541	15,122
Deferred tax liabilities:
Fixed assets	(3,775)	(3,813)
Right-of-use assets	(5,231)	(4,975)
Debt discounts	0	(155)
Percentage of completion	(205)	(92)
Total deferred tax liabilities	(9,211)	(9,035)
Net deferred tax asset	$ 4,330	$ 6,087

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate to Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%
State income taxes, net of federal tax effect	7.00%	6.30%
Change in uncertain tax benefits	0.00%	(0.60%)
Stock based compensation – restricted stock	(1.10%)	2.00%
Return to provision adjustment	1.20%	(0.70%)
Permanent differences	1.90%	1.10%
Tax credits	(0.80%)	(2.70%)
CARES Act carryback	0	(0.094)
Effective tax rate	29.20%	17.00%

Operating Segments - Narrative

Operating Segments - Narrative (Details) - segment	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue, Major Customer [Line Items]
Number of operating segments	2
Number of reportable segments	2
GCR
Revenue, Major Customer [Line Items]
Number of reportable segments	1
GCR | Revenue, Segment Benchmark | Customer Concentration Risk | Customer One
Revenue, Major Customer [Line Items]
Concentration risk, percentage	17.00%	14.00%
GCR | Revenue, Segment Benchmark | Customer Concentration Risk | Customer Two
Revenue, Major Customer [Line Items]
Concentration risk, percentage	12.00%
ODR
Revenue, Major Customer [Line Items]
Number of reportable segments	1

Operating Segments - Segment In

Operating Segments - Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenue	$ 490,351	$ 568,209
Gross profit	85,910	81,386
Selling, general and administrative	71,436	63,601
Amortization of intangibles	484	630
Operating income	13,990	17,155
Interest expense, net	(2,568)	(8,627)
Loss on debt extinguishment	(1,961)	0
Gain (loss) on change in fair value of warrant liability	14	(1,634)
Gain on sale of property and equipment	2	95
Total unallocated amounts	(4,513)	(10,166)
Income before income taxes	9,477	6,989
Depreciation and amortization	5,948	6,171
Operating Segments | GCR
Segment Reporting Information [Line Items]
Revenue	350,015	440,979
Gross profit	45,409	45,115
Selling, general and administrative	37,558	37,708
Depreciation and amortization	4,085	4,187
Operating Segments | ODR
Segment Reporting Information [Line Items]
Revenue	140,336	127,230
Gross profit	40,501	36,271
Selling, general and administrative	31,277	24,825
Depreciation and amortization	1,379	1,354
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Selling, general and administrative	2,601	1,068
Depreciation and amortization	$ 484	$ 630

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	Jan. 26, 2022	Apr. 17, 2020	Jan. 23, 2020	Nov. 13, 2019	Dec. 31, 2021
Loss Contingencies [Line Items]
Payment to acquire workers' compensation and general liability insurance					$ 250,000
Malpractice insurance, annual coverage limit					4,400,000
Surety Bond
Loss Contingencies [Line Items]
Long-term debt					$ 159,200,000
Pending Litigation | Lanzo
Loss Contingencies [Line Items]
Loss contingency, damages sought, value				$ 400,000
Pending Litigation | Bernards
Loss Contingencies [Line Items]
Loss contingency, damages sought, value			$ 3,000,000
Pending Litigation | LA Excavating, Inc. vs. Limbach Company LP
Loss Contingencies [Line Items]
Loss contingency, damages sought, value		$ 1,000,000
Pending Litigation | Suffolk | Subsequent Event
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 300,000

Commitments and Contingencies_2

Commitments and Contingencies - Components of Self-Insurance (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Current liability — workers' compensation and general liability	$ 184	$ 197
Current liability — medical and dental	456	764
Non-current liability	451	890
Total liability	1,091	1,851
Restricted cash	$ 113	$ 113

Leases - Narrative (Details)

Leases - Narrative (Details)	Dec. 02, 2021USD ($)extension	Jun. 30, 2021USD ($)ft²	Dec. 31, 2021USD ($)
Ground Floor Space | Southern California Region
Lessee, Lease, Description [Line Items]
Subleased area (in sq ft) | ft²		71,787
Sublease annual base rent		$ 600,000
Sublease annual base rent increase percentage		3.00%
Sublease income			$ 400,000
Jake Marshall Transaction | Full-time Employee | Land and facilities
Lessee, Lease, Description [Line Items]
Lease term	10 years
Number of lease extensions | extension	2
Term of lease extensions	2 years
Jake Marshall Transaction | Full-time Employee | Land and facilities | For the first 5 years
Lessee, Lease, Description [Line Items]
Lease term	5 years
Monthly base rent	$ 37,500
Jake Marshall Transaction | Full-time Employee | Land and facilities | For years 6 through 10
Lessee, Lease, Description [Line Items]
Lease term	5 years
Monthly base rent	$ 45,000

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheets Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 20,119	$ 18,751
Property and equipment, net	4,916	6,242
Total lease assets	25,035	24,993
Current operating lease liabilities	$ 4,366	$ 3,929
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Long-term Debt, Current Maturities	Long-term Debt, Current Maturities
Current portion of long-term debt	$ 2,451	$ 2,536
Long-term operating lease liabilities	$ 16,576	$ 15,459
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt	Long-term debt
Long-term debt	$ 2,681	$ 3,923
Total lease liabilities	26,074	25,847
Operating lease, accumulated amortization	15,900	11,900
Finance lease, accumulated amortization	$ 5,855	$ 5,263

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Finance lease cost, amortization, cost of revenue	$ 2,622,000	$ 2,711,000
Finance lease cost, interest expense, net	305,000	363,000
Total lease cost	8,051,000	8,084,000
Cost of revenue
Lessee, Lease, Description [Line Items]
Operating lease cost	2,901,000	3,527,000
Cost of revenue | Operating Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	500,000	700,000
Cost of revenue | Finance Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	2,800,000	2,400,000
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Operating lease cost	2,223,000	1,483,000
Selling, general and administrative expenses | Operating Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	400,000	300,000
Selling, general and administrative expenses | Finance Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	$ 0	$ 0

Leases - Future Minimum Lease C

Leases - Future Minimum Lease Commitments For Finance and Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finance Leases
2022	$ 2,658
2023	1,662
2024	851
2025	289
2026	12
Thereafter	0
Total minimum lease payments	5,472
Amounts representing interest	(340)
Present value of net minimum lease payments	5,132	$ 6,459
Operating Leases
2022	4,593
2023	3,289
2024	2,670
2025	2,141
2026	1,720
Thereafter	6,598
Total minimum lease payments	21,011
Sublease Receipts
2022	(657)
2023	(677)
2024	(697)
2025	(718)
2026	(740)
Thereafter	(250)
Total minimum lease payments	(3,739)
Non-Related Party
Operating Leases
2022	4,800
2023	3,516
2024	2,917
2025	2,409
2026	2,010
Thereafter	2,033
Total minimum lease payments	17,685
Related Party
Operating Leases
2022	450
2023	450
2024	450
2025	450
2026	450
Thereafter	4,815
Total minimum lease payments	$ 7,065

Leases - Terms and Discount Rat

Leases - Terms and Discount Rates (Details)	Dec. 31, 2021	Dec. 31, 2020
Weighted average lease term (in years)
Operating	7 years 1 month 6 days	5 years 5 months 23 days
Finance	2 years 6 months 3 days	2 years 9 months 10 days
Weighted average discount rate
Operating	4.68%	4.83%
Finance	5.27%	5.50%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 4,938	$ 5,164
Operating cash flows from finance leases	305	363
Financing cash flows from finance leases	2,623	2,664
Right-of-use assets exchanged for lease liabilities
Right of use assets obtained in exchange for new operating lease liabilities	5,417	1,096
Right of use assets obtained in exchange for new finance lease liabilities	1,296	2,624
Right of use assets disposed or adjusted modifying operating leases liabilities	219	621
Right of use assets disposed or adjusted modifying finance leases liabilities	$ 0	$ (86)

Retirement Plan (Details)

Retirement Plan (Details) - Supplemental Employee Retirement Plan - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay	100.00%
Defined contribution plan, maximum annual contributions per employee, percent	4.00%
Defined contribution plan, employer discretionary contribution amount	$ 2,300,000	$ 2,200,000
Defined contribution plan, employer discretionary profit sharing contribution amount	$ 0	$ 0

Multiemployer Pension Plans - N

Multiemployer Pension Plans - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)plan	Dec. 31, 2020USD ($)
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	51.00%
Multiemployer plan, contributions	$ 14,318	$ 16,109
CBAs
Multiemployer Plans [Line Items]
Multiemployer plan, contributions	$ 36,300	41,800
MEPP
Multiemployer Plans [Line Items]
Multiemployer plans number of employer | plan	40
MEPP | CBAs
Multiemployer Plans [Line Items]
Multiemployer plan, contributions	$ 14,300	$ 16,100
MEPP | PPA
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	5.00%
MEPP | CBA
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	10.00%

Multiemployer Pension Plans - (

Multiemployer Pension Plans - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Multiemployer Plans [Line Items]
Contributions	$ 14,318	$ 16,109
Heating, Piping and Refrigeration Pension Fund
Multiemployer Plans [Line Items]
Contributions	851	1,045
Plumbers Local No 98 Defined Benefit Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,386	1,658
United Association National Pension Fund
Multiemployer Plans [Line Items]
Contributions	700	947
Pipefitters Local 636 Defined Benefit Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,437	1,206
Sheet Metal Workers' Pension Plan of Southern California, Arizona and Nevada
Multiemployer Plans [Line Items]
Contributions	297	1,322
Sheet Metal Workers' National Pension Fund
Multiemployer Plans [Line Items]
Contributions	701	1,144
Sheet Metal Workers Local Union No. 80 Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,571	1,383
Sheet Metal Workers Local 98 Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,003	945
Steamfitters Local Union No. 420 Pension Fund
Multiemployer Plans [Line Items]
Contributions	526	591
Pipefitters Union Local No. 537 Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,805	1,337
Plumbers & Pipefitters Local No 189 Pension Plan
Multiemployer Plans [Line Items]
Contributions	489	598
Plumbers & Pipefitters of Local Union No. 333 Pension Fund
Multiemployer Plans [Line Items]
Contributions	1,694	1,329
Southern California Pipe Trades Retirement Fund
Multiemployer Plans [Line Items]
Contributions	161	662
Electrical Workers Local No. 26 Pension Trust Fund
Multiemployer Plans [Line Items]
Contributions	429	348
Plumbers Union Local No. 12 Pension
Multiemployer Plans [Line Items]
Contributions	131	261
Sheet Metal Workers Local 7, Zone 1 Pension Plan
Multiemployer Plans [Line Items]
Contributions	293	383
Plumbers & Steamfitters Local 577 Pension Plan
Multiemployer Plans [Line Items]
Contributions	277	208
Laborers District Council Pension and Disability Trust Fund No. 2
Multiemployer Plans [Line Items]
Contributions	53	147
Laborers District Council Pension and Disability Trust Fund No. 2
Multiemployer Plans [Line Items]
Contributions	33	37
National Electrical Benefit Fund
Multiemployer Plans [Line Items]
Contributions	1	111
Airconditioning and Refrigeration Industry Retirement Trust Fund
Multiemployer Plans [Line Items]
Contributions	130	144
Plumbers and Steamfitters Local 486 Pension Fund
Multiemployer Plans [Line Items]
Contributions	15	40
Steamfitters Local #449 Pension Plan
Multiemployer Plans [Line Items]
Contributions	68	109
United Association Local Union No. 322 Pension Plan
Multiemployer Plans [Line Items]
Contributions	24	18
Sheet Metal Workers Local 224 Pension Fund
Multiemployer Plans [Line Items]
Contributions	21	20
Plumbers Local 27 Pension Fund
Multiemployer Plans [Line Items]
Contributions	0	18
Plumbers and Pipefitters Local Union No. 43 Pension Fund
Multiemployer Plans [Line Items]
Contributions	95	0
All other plans
Multiemployer Plans [Line Items]
Contributions	$ 127	$ 98

Management Incentive Plans - Na

Management Incentive Plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 2,600,000	$ 1,100,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Number of awards granted (in shares)	127,407	178,633
Unrecognized stock-based compensation expense	$ 2,300,000
Period to recognized stock-based compensation expense	1 year 9 months
Aggregate fair value of vested awards	$ 1,600,000	$ 1,100,000
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Number of awards granted (in shares)	185,367	96,500
Share-based compensation expense	$ 0	$ 0	$ 0
PRSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares to be issued under grant	0.00%
PRSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares to be issued under grant	150.00%
MRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)	0	0
Unrecognized stock-based compensation expense	$ 200,000
Period to recognized stock-based compensation expense	1 year 3 months 3 days
Restated 2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)	2,250,000
Restated 2016 Plan | PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)	185,367	96,500

Management Incentive Plans - RS

Management Incentive Plans - RSUs Activity (Details) - RSUs - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Awards
Unvested, beginning balance (in shares)	285,799	328,575
Granted (in shares)	127,407	178,633
Vested (in shares)	(144,784)	(211,300)
Forfeited (in shares)	(2,333)	(10,109)
Unvested, ending balance (in shares)	266,089	285,799
Weighted-Average Grant Date Fair Values
Unvested, beginning balance (in usd per share)	$ 6.32	$ 7.83
Granted (in usd per share)	11.99	2.64
Vested (in usd per share)	7.35	8.12
Forfeited (in usd per share)	8.27	6.80
Unvested, ending balance (in usd per share)	$ 8.45	$ 6.32

Management Incentive Plans - PR

Management Incentive Plans - PRSUs Activity (Details) - PRSUs - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Awards
Unvested, beginning balance (in shares)	99,500	62,307
Granted (in shares)	185,367	96,500
Vested (in shares)	0	0
Forfeited (in shares)	(4,167)	(59,307)
Unvested, ending balance (in shares)	280,700	99,500
Weighted-Average Grant Date Fair Values
Unvested, beginning balance (in usd per share)	$ 4.23	$ 12.62
Granted (in usd per share)	12.26	3.67
Vested (in usd per share)	0	0
Forfeited (in usd per share)	8.92	12.95
Unvested, ending balance (in usd per share)	$ 9.46	$ 4.23

Management Incentive Plans - MR

Management Incentive Plans - MRSUs Activity (Details) - MRSUs - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Awards
Unvested, beginning balance (in shares)	102,500	125,000
Granted (in shares)	0	0
Vested (in shares)	0	0
Forfeited (in shares)	0	(22,500)
Unvested, ending balance (in shares)	102,500	102,500
Weighted-Average Grant Date Fair Values
Unvested, beginning balance (in usd per share)	$ 8.26	$ 6.58
Granted (in usd per share)	0	0
Vested (in usd per share)	0	0
Forfeited (in usd per share)	0	6.58
Unvested, ending balance (in usd per share)	$ 8.26	$ 8.26

Management Incentive Plans - As

Management Incentive Plans - Assumptions Used to Value MRSUs (Details) - MRSUs	12 Months Ended
	Dec. 31, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.56%
Dividend yield	0.00%
Remaining performance period (years)	3 years 11 months 1 day
Expected volatility	28.54%
Estimated grant date fair value (per share)	$ 6.58
Derived service period (years)	1 year 11 months 15 days