Limbach (LMB) 10-Q 10 Nov 21 2021 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2021	Nov. 09, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		10,304,242
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001606163
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 33,302	$ 42,147
Restricted cash	113	113
Accounts receivable (net of allowance for doubtful accounts of $285 and $266 as of September 30, 2021 and December 31, 2020, respectively)	98,319	85,767
Contract assets	72,193	67,098
Income tax receivable	217	0
Other current assets	5,539	4,292
Total current assets	209,683	199,417
Property and equipment, net	16,710	19,700
Intangible assets, net	11,386	11,681
Goodwill	6,129	6,129
Operating lease right-of-use assets	15,802	18,751
Deferred tax asset	5,696	6,087
Other assets	272	392
Total assets	265,678	262,157
Current liabilities:
Current portion of long-term debt	8,460	6,536
Current operating lease liabilities	4,061	3,929
Accounts payable, including retainage	70,895	66,763
Contract liabilities	37,003	46,648
Accrued income taxes	245	1,671
Accrued expenses and other current liabilities	22,420	24,747
Total current liabilities	143,084	150,294
Long-term debt	23,094	36,513
Long-term operating lease liabilities	12,495	15,459
Other long-term liabilities	4,030	6,159
Total liabilities	182,703	208,425
Commitments and contingencies
STOCKHOLDERS’ EQUITY
Common stock, $0.0001 par value; 100,000,000 shares authorized, 10,274,242 issued and outstanding as of September 30, 2021 and 7,926,137 at December 31, 2020	1	1
Additional paid-in capital	84,419	57,612
Accumulated deficit	(1,445)	(3,881)
Total stockholders’ equity	82,975	53,732
Total liabilities and stockholders’ equity	$ 265,678	$ 262,157

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ (285)	$ (266)
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)	10,274,242	7,926,137
Common stock, shares, outstanding (in shares)	10,274,242	7,926,137

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 129,177	$ 163,856	$ 363,540	$ 437,813
Cost of revenue	104,714	139,685	303,158	375,083
Gross profit	24,463	24,171	60,382	62,730
Operating expenses:
Selling, general and administrative	18,302	17,045	52,679	47,596
Amortization of intangibles	87	109	295	526
Total operating expenses	18,389	17,154	52,974	48,122
Operating income	6,074	7,017	7,408	14,608
Other (expenses) income:
Interest expense, net	(424)	(2,154)	(2,140)	(6,449)
(Loss) gain on disposition of property and equipment	(49)	3	(41)	18
Loss on early debt extinguishment	0	0	(1,961)	0
(Loss) gain on change in fair value of warrant liability	0	(1,371)	14	(1,312)
Total other expenses	(473)	(3,522)	(4,128)	(7,743)
Income before income taxes	5,601	3,495	3,280	6,865
Income tax provision	1,615	970	844	1,445
Net income	$ 3,986	$ 2,525	$ 2,436	$ 5,420
Income per common share:
Basic (in usd per share)	$ 0.39	$ 0.32	$ 0.25	$ 0.69
Diluted (in usd per share)	$ 0.38	$ 0.31	$ 0.24	$ 0.68
Weighted average number of shares outstanding:
Basic (in shares)	10,266,486	7,890,074	9,915,966	7,844,587
Diluted (in shares)	10,491,863	8,107,149	10,145,470	7,969,857

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	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)
Stock-based compensation	295		295
Shares issued related to vested restricted stock units (in shares)		104,905
Shares issued related to vested restricted stock units	0
Net income	(52)			(52)
Ending balance (in shares) at Mar. 31, 2020		7,793,863
Ending balance at Mar. 31, 2020	47,113	$ 1	56,852	(9,740)
Beginning balance (in shares) at Dec. 31, 2019		7,688,958
Beginning balance at Dec. 31, 2019	46,870	$ 1	56,557	(9,688)
Net income	5,420
Ending balance (in shares) at Sep. 30, 2020		7,894,202
Ending balance at Sep. 30, 2020	53,127	$ 1	57,394	(4,268)
Beginning balance (in shares) at Mar. 31, 2020		7,793,863
Beginning balance at Mar. 31, 2020	47,113	$ 1	56,852	(9,740)
Stock-based compensation	140		140
Shares issued related to vested restricted stock units (in shares)		59,514
Shares issued related to vested restricted stock units	0
Net income	2,947			2,947
Ending balance (in shares) at Jun. 30, 2020		7,853,377
Ending balance at Jun. 30, 2020	50,200	$ 1	56,992	(6,793)
Stock-based compensation	304		304
Shares issued related to vested restricted stock units (in shares)		10,000
Shares issued related to vested restricted stock units	0
Stock issued related to employee stock purchase plan (in shares)		30,825
Shares issued related to employee stock purchase plan	98		98
Net income	2,525			2,525
Ending balance (in shares) at Sep. 30, 2020		7,894,202
Ending balance at Sep. 30, 2020	53,127	$ 1	57,394	(4,268)
Beginning balance (in shares) at Dec. 31, 2020		7,926,137
Beginning balance at Dec. 31, 2020	53,732	$ 1	57,612	(3,881)
Stock-based compensation	677		677
Shares issued related to vested restricted stock units (in shares)		89,446
Shares issued related to vested restricted stock units	0
Tax withholding related to vested restricted stock units	(183)		(183)
Stock issued related to employee stock purchase plan (in shares)		8,928
Shares issued related to employee stock purchase plan	92		92
Shares issued related to exercise of warrants (in shares)		172,869
Shares issued related to the exercise of warrants	1,989		1,989
Shares issued related to offering (in shares)		2,051,025
Shares issued related to sale of common stock	22,773		22,773
Net income	(2,282)			(2,282)
Ending balance (in shares) at Mar. 31, 2021		10,248,405
Ending balance at Mar. 31, 2021	76,798	$ 1	82,960	(6,163)
Beginning balance (in shares) at Dec. 31, 2020		7,926,137
Beginning balance at Dec. 31, 2020	53,732	$ 1	57,612	(3,881)
Net income	2,436
Ending balance (in shares) at Sep. 30, 2021		10,274,242
Ending balance at Sep. 30, 2021	82,975	$ 1	84,419	(1,445)
Beginning balance (in shares) at Mar. 31, 2021		10,248,405
Beginning balance at Mar. 31, 2021	76,798	$ 1	82,960	(6,163)
Stock-based compensation	636		636
Shares issued related to vested restricted stock units (in shares)		3,291
Shares issued related to vested restricted stock units	0
Tax withholding related to vested restricted stock units	(7)		(7)
Net income	732			732
Ending balance (in shares) at Jun. 30, 2021		10,251,696
Ending balance at Jun. 30, 2021	78,159	$ 1	83,589	(5,431)
Stock-based compensation	703		703
Shares issued related to vested restricted stock units (in shares)		6,401
Shares issued related to vested restricted stock units	0
Stock issued related to employee stock purchase plan (in shares)		16,140
Shares issued related to employee stock purchase plan	127		127
Shares issued related to exercise of warrants (in shares)		5
Shares issued related to the exercise of warrants	0
Net income	3,986			3,986
Ending balance (in shares) at Sep. 30, 2021		10,274,242
Ending balance at Sep. 30, 2021	$ 82,975	$ 1	$ 84,419	$ (1,445)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 2,436	$ 5,420
Adjustments to reconcile net income to cash (used in) provided by operating activities:
Depreciation and amortization	4,353	4,635
Provision for doubtful accounts	126	62
Stock-based compensation expense	2,016	739
Noncash operating lease expense	3,152	3,033
Amortization of debt issuance costs	251	1,620
Deferred income tax provision	391	211
Loss (gain) on sale of property and equipment	41	(18)
Loss on early debt extinguishment	1,961	0
(Gain) loss on change in fair value of warrant liability	(14)	1,312
Changes in operating assets and liabilities:
Accounts receivable	(12,678)	(19,834)
Contract assets	(5,095)	8,612
Other current assets	(1,243)	270
Accounts payable, including retainage	4,131	2,695
Prepaid income taxes	(217)	(192)
Accrued taxes payable	(1,426)	1,947
Contract liabilities	(9,645)	18,715
Operating lease liabilities	(3,036)	(3,229)
Accrued expenses and other current liabilities	(2,173)	8,925
Other long-term liabilities	(112)	306
Net cash (used in) provided by operating activities	(16,781)	35,229
Cash flows from investing activities:
Proceeds from sale of property and equipment	421	65
Advances to joint ventures	(2)	(3)
Purchase of property and equipment	(687)	(1,116)
Net cash used in investing activities	(268)	(1,054)
Cash flows from financing activities:
Proceeds from Wintrust Term Loan	30,000	0
Payments on Wintrust Term Loan	0	7,250
Payments on 2019 Revolving Credit Facility	0	(7,250)
Prepayment penalty and other costs associated with early debt extinguishment	(1,376)	0
Proceeds from the sale of common stock	22,773	0
Proceeds from the exercise of warrants	1,989	0
Payments on finance leases	(1,966)	(1,966)
Payments of debt issuance costs	(593)	0
Taxes paid related to net-share settlement of equity awards	(401)	(102)
Proceeds from contributions to Employee Stock Purchase Plan	278	149
Net cash provided by (used in) financing activities	8,204	(2,919)
(Decrease) increase in cash, cash equivalents and restricted cash	(8,845)	31,256
Cash, cash equivalents and restricted cash, beginning of period	42,260	8,457
Cash, cash equivalents and restricted cash, end of period	33,415	39,713
Noncash investing and financing transactions:
Right of use assets obtained in exchange for new operating lease liabilities	156	924
Right of use assets obtained in exchange for new finance lease liabilities	846	2,399
Right-of-use assets disposed or adjusted modifying operating leases liabilities	47	586
Right-of-use assets disposed or adjusted modifying finance leases liabilities	0	(64)
Interest paid	2,138	4,817
Cash paid (received) for income taxes	2,096	(629)
Wintrust Term Loan
Cash flows from financing activities:
Payments of Term Loans	(3,500)	0
2019 Refinancing Term Loan
Cash flows from financing activities:
Payments of Term Loans	$ (39,000)	$ (1,000)

Business and Organization

Business and Organization	9 Months Ended
	Sep. 30, 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. 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 favorable pricing or other terms, and/or difficulty in collection of our accounts receivable. Our clients may face budget deficits or other financial constraints that prohibit them from funding proposed and existing projects. During the fourth quarter of 2020 and the nine months ended September 30, 2021, several of our business units experienced slowdowns in the closing of sales related to the ongoing effects of the pandemic, which impacted our revenue and profitability. These impacts may continue as the pandemic persists. Further, ongoing economic instability in the global markets, including from the pandemic, could limit our ability to access the capital markets at a time when we would like, or need, to raise capital, which could have an impact on

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation 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, and Harper Limbach Construction LLC for all periods presented. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) for interim financial information and with the requirements of Form 10-Q and Rule 8-03 of Regulation S-X for smaller reporting companies. Consequently, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading. Readers of this report should refer to the consolidated financial statements and the notes thereto included in the Company's most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 25, 2021. Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheets, Condensed Consolidated Statements of Operations, Condensed Consolidated Statements of Stockholders’ Equity and Condensed Consolidated Statements of Cash Flows for the periods presented are unaudited. Also, within the notes to the condensed consolidated financial statements, the Company has included unaudited information for these interim periods. These unaudited interim condensed consolidated financial statements have been prepared in accordance with GAAP. In the Company's opinion, the accompanying unaudited condensed consolidated financial statements contain all normal and recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2021, its results of operations and its cash flows for the three and nine months ended September 30, 2021. The results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021. The Condensed Consolidated Balance Sheet as of December 31, 2020 was derived from the Company's audited financial statements included in its Annual Report on Form 10-K filed with the SEC on March 25, 2021, but is presented as condensed and does not contain all of the footnote disclosures from the annual financial statements. Recently Adopted Accounting Standards 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 condensed 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 condensed 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 condensed consolidated financial statements. Management has identified that its credit agreement utilizes LIBOR as a benchmark rate. Management will continue to evaluate the impact of adopting reference rate reform as the LIBOR benchmark rate within the credit agreement is phased out. 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 condensed consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers The 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 costs in excess of billings and estimated earnings and amounts due under retainage provisions. The components of the contract asset balances as of the respective dates were as follows: (in thousands) September 30, 2021 December 31, 2020 Change Contract assets Costs in excess of billings and estimated earnings $ 39,772 $ 31,894 $ 7,878 Retainage receivable 32,421 35,204 (2,783) Total contract assets $ 72,193 $ 67,098 $ 5,095 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 claims and unapproved change orders as recorded in contract assets and contract liabilities in the condensed consolidated balance sheets was $39.2 million and $33.6 million as of September 30, 2021 and December 31, 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 Contract liabilities include billings in excess of costs and estimated earnings and provisions for losses. The components of the contract liability balances as of the respective dates were as follows: (in thousands) September 30, 2021 December 31, 2020 Change Contract liabilities Billings in excess of costs and estimated earnings $ 36,517 $ 46,020 $ (9,503) Provisions for losses 486 628 (142) Total contract liabilities $ 37,003 $ 46,648 $ (9,645) Billings in excess of costs and estimated earnings 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 condensed 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 overbilling position for contracts in process consist of the following: (in thousands) September 30, 2021 December 31, 2020 Revenue earned on uncompleted contracts $ 718,366 $ 752,564 Less: Billings to date (715,111) (766,690) Net underbilling (overbilling) $ 3,255 $ (14,126) (in thousands) September 30, 2021 December 31, 2020 Costs in excess of billings and estimated earnings $ 39,772 $ 31,894 Billings in excess of costs and estimated earnings (36,517) (46,020) Net underbilling (overbilling) $ 3,255 $ (14,126) Revisions in Contract Estimates For the three and nine months ended September 30, 2021 and 2020, the Company recorded revisions in its contract estimates for certain GCR and ODR projects. For the three months ended September 30, 2021, total net gross profit write-ups were $1.2 million compared total net gross profit write-downs of $0.8 million for the three months ended September 30, 2020. For projects having a material gross profit impact of $0.25 million or more for the three months ended September 30, 2021, this resulted in material gross profit write-downs on three GCR segment projects of $1.4 million. Of the material GCR segment write-downs, one project was within the New England region for $0.6 million, and two projects were within the Southern California region for a total of $0.8 million. The Company also recorded material gross profit write-ups on three GCR segment projects of $1.2 million. Of the material GCR segment write-ups, one project was within the New England region for $0.6 million and two were within the Florida region for a total of $0.6 million. For the three months ended September 30, 2020, the Company recorded material revisions in its contract estimates on five GCR projects which resulted in gross profit write-downs of $2.4 million. Three of these projects were within the Southern California region for a total of $1.8 million. The Company also recorded a $0.4 million material project revision resulting in a gross profit write-up on one GCR project within the Southern California region for the three months ended September 30, 2020. For the nine months ended September 30, 2021 and 2020, total net gross profit write-downs were $1.3 million and $4.2 million, respectively. For projects having a material gross profit impact of $0.25 million or more, the Company recorded gross profit write-downs on nine GCR segment projects of $5.3 million and one ODR project for $0.3 million. Of the material GCR segment write-downs, three projects were within the Southern California region for a total of $1.8 million, two projects were within the Michigan region for a total of $1.3 million, two projects were within the Eastern Pennsylvania region for a total of $1.2 million, one project was within the New England region for $0.7 million, and one project was within the Mid-Atlantic region for $0.3 million. The Company also materially wrote-down one ODR segment project within the Eastern Pennsylvania region for $0.3 million. The Company also recorded material GCR segment gross profit write-ups of $2.9 million on seven GCR segment projects. Of the material GCR segment write-ups, two projects were within the Florida region for a total of $0.9 million, one project was within the Michigan region for $0.7 million, two projects were within the Ohio region for a total of $0.6 million, one project was within the New England region for $0.4 million and one project was within the Mid-Atlantic region for $0.3 million. For the nine months ended September 30, 2020, the Company recorded eleven material gross profit write-downs and three gross profit write-ups on material GCR projects, resulting in aggregate revisions of $7.5 million and $1.6 million, respectively. 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 September 30, 2021, the aggregate amount of the transaction prices allocated to the remaining performance obligations of the Company's GCR and ODR segment contracts were $345.5 million and $52.8 million, respectively. The Company estimates that 25% and 37% of its GCR and ODR remaining performance obligations as of September 30, 2021, respectively, will be recognized as revenue during the remainder of 2021. 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 contracts can be canceled for convenience at any time by the Company or the customer without considerable cost incurred by the customer.

Goodwill and Intangibles

Goodwill and Intangibles	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles Goodwill Goodwill was $6.1 million as of September 30, 2021 and December 31, 2020 and is entirely associated with the Company's ODR segment. The Company tests its goodwill and indefinite-lived intangible assets 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. 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 during the three months ended September 30, 2021. 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. Intangible Assets Intangible assets are comprised of the following: (in thousands) Gross Accumulated Net intangible September 30, 2021 (1) Amortized intangible assets: Customer relationships – ODR $ 4,710 $ (3,396) $ 1,314 Favorable leasehold interests (2) 190 (78) 112 Total amortized intangible assets 4,900 (3,474) 1,426 Unamortized intangible assets: Trade name 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 14,860 $ (3,474) $ 11,386 (in thousands) Gross Accumulated Net intangible December 31, 2020 (1) Amortized intangible assets: Customer relationships – ODR $ 4,710 $ (3,112) $ 1,598 Favorable leasehold interests 530 (407) 123 Total amortized intangible assets 5,240 (3,519) 1,721 Unamortized intangible assets: Trade name 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-Construction 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. (2) 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. 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. Favorable leasehold interest-related intangible assets are amortized on a straight-line basis over the remaining lease terms. Total amortization expense for the Company's definite-lived intangible assets was $0.1 million and $0.3 million for the three and nine months ended September 30, 2021, respectively, and $0.1 million and $0.5 million for the three and nine months ended September 30, 2020, respectively. The Company has previously 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. 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 revenues. 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 three and nine months ended September 30, 2021 and 2020.

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Debt Long-term debt consists of the following obligations as of: (in thousands) September 30, 2021 December 31, 2020 2019 Refinancing Term Loan - term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022 $ — $ 39,000 2019 Revolving Credit Facility — — Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in March 2021) plus interest through February 2026 26,500 — Wintrust Revolving Loan — — Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.70% to 6.45% through 2025 5,338 6,459 Total debt 31,838 45,459 Less - Current portion of long-term debt (8,460) (6,536) Less - Unamortized discount and debt issuance costs (284) (2,410) Long-term debt $ 23,094 $ 36,513 On February 24, 2021 (the “2021 Refinancing Date”), the Company refinanced its 2019 Refinancing Term Loan (defined below) and 2019 Revolving Credit Facility (defined below) 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 (defined below) 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 - 2019 Term Loans On April 12, 2019 (the “Refinancing Closing Date”), LFS entered into a financing agreement (as amended, 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, as origination agent (“CB”). 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”). On November 14, 2019, the Company entered into an amendment to the 2019 Refinancing Agreement which, among other things, amended the interest rate and certain covenants in the 2019 Refinancing Agreement. Prior to its refinancing in February 2021, the 2019 Refinancing Agreement would have matured in April 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 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 interest rate on borrowings under the 2019 Refinancing Agreement was, at the option of LFS and its subsidiaries, either LIBOR (with a 2.00% floor) plus 11.00% or a base rate (with a 3.00% minimum) plus 10.00%. At the 2021 Refinancing Date and September 30, 2020, the interest rate in effect on the 2019 Refinancing Term Loan was 13.00%. 2019 Refinancing Agreement - CB Warrants In connection with the 2019 Refinancing Agreement, on the 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 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 Refinancing Closing Date through the 2021 Refinancing Date, 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 does 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 in the 2019 Refinancing Agreement was evaluated as an embedded derivative liability and bifurcated from the 2019 Term Loans as it represented a non-credit related embedded feature that provides 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 Refinancing Closing Date. The Company estimated these fair values by using the Black-Scholes-Merton option pricing model and a probability-weighted discounted cash flow approach. See Note 7 for further discussion on the fair value measurements associated with the CB Warrants. 2019 ABL Credit Agreement On the 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 November 14, 2019, the Company entered into an amendment to the 2019 ABL Credit Agreement (as amended, 2019 ABL Credit Amendment Number One and Waiver), which amended certain provisions under the 2019 ABL Credit Agreement. The interest rate on borrowings under the 2019 ABL Credit Agreement was, at the option of LFS and its subsidiaries, 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 the 2021 Refinancing Date and September 30, 2020, the interest rate in effect on the 2019 ABL Credit Agreement was 5.25%. As of the 2021 Refinancing Date and December 31, 2020, the Company had irrevocable letters of credit in the amount of $3.4 million with its lender to secure obligations under its self-insurance program. Prior to its refinancing in February 2021, the 2019 ABL Agreement would have matured in April 2022. 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 “2021 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 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 bears interest, at the 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 “Senior Leverage Ratio”). The Wintrust Term Loan bears 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 is 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. The Wintrust Revolving Loan will mature and become due and payable by LFS on February 24, 2026. The 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 Wintrust Loans shall be jointly and severally guaranteed by each Wintrust Guarantor. The 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 Credit Agreement. The 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 2.25 to 1.00 through December 31, 2021, and stepping down to 2.00 to 1.00 at all times thereafter, (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 March 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 September 30, 2021, the Company was in compliance with all financial maintenance covenants as required by the Wintrust Loans. The following is a summary of the additional margin and commitment fees payable on the available Wintrust Term Loan and Wintrust Revolving Loan credit commitment: Level Senior Leverage Ratio Additional Margin for Additional Margin for Additional Margin for Eurodollar Term loans Additional Margin for Eurodollar Revolving loans Commitment Fee I Greater than 1.00 to 1.00 1.00 % 0.50 % 4.00 % 3.50 % 0.25 % II Less than or equal to 1.00 to 1.00 0.25 % — % 3.50 % 3.00 % 0.25 % At September 30, 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%.

Equity

Equity	9 Months Ended
	Sep. 30, 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”). September 30, 2021 December 31, 2020 Public Warrants (1)(6) — 2,300,000 Private Warrants (2)(6) — 99,000 $15 Exercise Price Sponsor 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 share 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. On May 24, 2020, the Board of Directors approved further amendments to the Company's initial Omnibus Incentive Plan (“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 extend 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 extend 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 13 for a discussion of the Company's management incentive plans for restricted stock units (“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 not less than 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 1 and July 1 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. In January 2021 and July 2021, the Company issued 8,928 and 16,140 shares of its common stock, respectively, to participants in the ESPP who contributed to the plan through the December 31, 2020 and June 30, 2021 offering periods, respectively. For the nine months ended September 30, 2020, the Company issued a total of 39,753 shares of its common stock to participants in the ESPP who contributed to the plan during the offering period ending June 30, 2020. As of September 30, 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 in connection with the exercise of the over-allotment option.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
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. As discussed in Note 5, prior to its termination as a result of the 2021 Refinancing, 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 Condensed Consolidated Balance Sheets. 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 September 30, 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 three and nine months ended September 30, 2020, the Company recorded other expense of $1.4 million and $1.3 million to reflect the change in the CB Warrants liability. The carrying values of cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to the short maturity of the instruments; as such, their fair values are Level 1 fair value measurements. The carrying values of borrowings under the 2019 Refinancing Term Loan (prior to its termination), the Wintrust Term Loan, the 2019 Revolving Credit Facility (prior to its termination) and the Wintrust Revolving Loan approximate fair value due to the variable rates on such debt. As of February 24, 2021 and December 31, 2020, the Company determined that the fair value of the 2019 Revolving Term Loan was $39.0 million. As of September 30, 2021, the Company determined that the fair value of the Wintrust Term Loan was $26.5 million. Such fair values were determined using discounted estimated future cash flows using Level 3 inputs.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings per Share	Earnings per ShareThe following table sets forth the computation of the basic and diluted earnings per share attributable to the Company's common shareholders for the three and nine months ended September 30, 2021 and 2020: Three months ended September 30, Nine Months Ended (in thousands, except per share amounts) 2021 2020 2021 2020 EPS numerator: Net income $ 3,986 $ 2,525 $ 2,436 $ 5,420 EPS denominator: Weighted average shares outstanding – basic 10,266 7,890 9,916 7,845 Impact of dilutive securities 226 217 229 125 Weighted average shares outstanding – diluted 10,492 8,107 10,145 7,970 EPS: Basic $ 0.39 $ 0.32 $ 0.25 $ 0.69 Diluted (1) $ 0.38 $ 0.31 $ 0.24 $ 0.68 (1) Diluted EPS assumes the dilutive effect of outstanding common stock warrants and RSUs using the treasury stock method . 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: Three months ended September 30, Nine Months Ended 2021 2020 2021 2020 Out-of-the-money warrants (see Note 6) (1) 1,885,202 4,576,799 3,571,833 4,576,799 Service-based RSUs (See Note 13) 290 — 155 538 Performance and market-based RSUs (2) 36,305 — 8,707 — Employee Stock Purchase Plan — 8,375 — 4,375 Total 1,921,797 4,585,174 3,580,695 4,581,712 (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 three and nine months ended September 30, 2021 and 2020, certain PRSU and MRSU awards (each defined in Note 13) 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.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is taxed as a C corporation. For interim periods, the provision for income taxes (including federal, state, local and foreign taxes) is calculated based on the estimated annual effective tax rate, adjusted for certain discrete items for the full fiscal year. Cumulative adjustments to the Company's estimate are recorded in the interim period in which a change in the estimated annual effective rate is determined. Each quarter the Company updates its estimate of the annual effective tax rate, and if its estimated tax rate changes, the Company makes a cumulative adjustment. The Company had an effective tax rate of 28.8% and 25.7% for the three and nine months ended September 30, 2021, respectively. For the three and nine months ended September 30, 2020, the Company had an effective tax rate of 27.8% and 21.1%, respectively. No valuation allowance was required as of September 30, 2021 or December 31, 2020. 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

Operating Segments

Operating Segments	9 Months Ended
	Sep. 30, 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 CODM evaluates performance based on income from operations of the respective segments 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 activity 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 and depreciation expense. All of the Company’s identifiable assets are located in the United States, which is where the Company is domiciled. Interest expense is not allocated to segments because of the corporate management of debt service including interest. Condensed consolidated segment information for the three and nine months ended September 30, 2021 and 2020 were as follows: Three months ended September 30, Nine Months Ended (in thousands) 2021 2020 2021 2020 Statement of Operations Data: Revenue: GCR $ 89,950 $ 130,498 $ 262,304 $ 345,921 ODR 39,227 33,358 101,236 91,892 Total revenue 129,177 163,856 363,540 437,813 Gross profit: GCR 12,754 14,848 31,034 38,043 ODR 11,709 9,323 29,348 24,687 Total gross profit 24,463 24,171 60,382 62,730 Selling, general and administrative: GCR 9,586 10,501 27,770 28,700 ODR 8,013 6,240 22,893 18,157 Corporate 703 304 2,016 739 Total selling, general and administrative 18,302 17,045 52,679 47,596 Amortization of intangibles 87 109 295 526 Operating income $ 6,074 $ 7,017 $ 7,408 $ 14,608 Less unallocated amounts: Interest expense, net (424) (2,154) (2,140) (6,449) Loss on early debt extinguishment — — (1,961) — (Loss) gain on disposition of property and equipment (49) 3 (41) 18 (Loss) gain on change in fair value of warrant liability — (1,371) 14 (1,312) Total unallocated amounts (473) (3,522) (4,128) (7,743) Income before income taxes $ 5,601 $ 3,495 $ 3,280 $ 6,865 Other Data: Depreciation and amortization: GCR $ 1,035 $ 1,046 $ 3,091 $ 3,108 ODR 267 340 967 1,001 Corporate 87 109 295 526 Total other data $ 1,389 $ 1,495 $ 4,353 $ 4,635 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.

Leases

Leases	9 Months Ended
	Sep. 30, 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 condensed consolidated balance sheets. 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. The following table summarizes the lease amounts included in the Company's condensed consolidated balance sheets: (in thousands) Classification on the Condensed Consolidated Balance Sheets September 30, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 15,802 $ 18,751 Finance Property and equipment, net (b) 5,116 6,242 Total lease assets $ 20,918 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,061 $ 3,929 Finance Current portion of long-term debt 2,460 2,536 Noncurrent Operating Long-term operating lease liabilities 12,495 15,459 Finance Long-term debt 2,878 3,923 Total lease liabilities $ 21,894 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.0 million at September 30, 2021 and $11.9 million at December 31, 2020. (b) Finance lease assets are recorded net of accumulated amortization of $5.8 million at September 30, 2021 and $5.3 million at December 31, 2020. The following table summarizes the lease costs included in the Company's condensed consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020: Three Months Ended Nine Months Ended (in thousands) Classification on the Condensed Consolidated Statement of Operations 2021 2020 2021 2020 Operating lease cost Cost of revenue (a) $ 716 $ 882 $ 2,088 $ 2,658 Operating lease cost Selling, general and administrative (a) 553 355 1,724 1,110 Finance lease cost Amortization Cost of revenue (b) 644 684 1,971 2,001 Interest Interest expense, net (b) 72 89 236 269 Total lease cost $ 1,985 $ 2,010 $ 6,019 $ 6,038 (a) Operating lease costs recorded in cost of sales includes $0.2 million and $0.4 million of variable lease costs for the three and nine months ended September 30, 2021, respectively, and $0.2 million and $0.5 million for the three and nine months ended September 30, 2020, respectively. In addition, $0.1 million and $0.3 million of variable leases costs are included in Selling, general and administrative for the three and nine months ended September 30, 2021, respectively, and zero and $0.2 million for the three and nine months ended September 30, 2020 respectively. These variable costs consist of the Company's proportionate share of operating expenses, real estate taxes and utilities. (b) Finance lease costs recorded in cost of revenue include variable lease costs of $0.7 million and $2.0 million for the three and nine months ended September 30, 2021 , respectively, and $0.6 million and $1.8 million for the three and nine months ended September 30, 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 for the three and nine months ended September 30, 2021 and 2020 . Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of September 30, 2021 were as follows: Year ending (in thousands): Finance Operating Remainder of 2021 $ 718 $ 1,242 2022 2,539 4,624 2023 1,544 3,516 2024 733 2,917 2025 169 2,409 Thereafter — 4,043 Total minimum lease payments $ 5,703 $ 18,751 Amounts representing interest (365) Present value of net minimum lease payments $ 5,338 The following is a summary of the lease terms and discount rates: September 30, 2021 December 31, 2020 Weighted average lease term (in years): Operating 4.99 5.48 Finance 2.48 2.78 Weighted average discount rate: Operating 4.84 % 4.83 % Finance 5.37 % 5.50 % The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Nine months ended September 30, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,696 $ 3,963 Operating cash flows from finance leases 236 269 Financing cash flows from finance leases 1,966 1,966 Right-of-use assets exchanged for lease liabilities: Operating leases $ 156 924 Finance leases 846 2,399 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 47 586 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — (64)
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 condensed consolidated balance sheets. 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. The following table summarizes the lease amounts included in the Company's condensed consolidated balance sheets: (in thousands) Classification on the Condensed Consolidated Balance Sheets September 30, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 15,802 $ 18,751 Finance Property and equipment, net (b) 5,116 6,242 Total lease assets $ 20,918 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,061 $ 3,929 Finance Current portion of long-term debt 2,460 2,536 Noncurrent Operating Long-term operating lease liabilities 12,495 15,459 Finance Long-term debt 2,878 3,923 Total lease liabilities $ 21,894 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.0 million at September 30, 2021 and $11.9 million at December 31, 2020. (b) Finance lease assets are recorded net of accumulated amortization of $5.8 million at September 30, 2021 and $5.3 million at December 31, 2020. The following table summarizes the lease costs included in the Company's condensed consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020: Three Months Ended Nine Months Ended (in thousands) Classification on the Condensed Consolidated Statement of Operations 2021 2020 2021 2020 Operating lease cost Cost of revenue (a) $ 716 $ 882 $ 2,088 $ 2,658 Operating lease cost Selling, general and administrative (a) 553 355 1,724 1,110 Finance lease cost Amortization Cost of revenue (b) 644 684 1,971 2,001 Interest Interest expense, net (b) 72 89 236 269 Total lease cost $ 1,985 $ 2,010 $ 6,019 $ 6,038 (a) Operating lease costs recorded in cost of sales includes $0.2 million and $0.4 million of variable lease costs for the three and nine months ended September 30, 2021, respectively, and $0.2 million and $0.5 million for the three and nine months ended September 30, 2020, respectively. In addition, $0.1 million and $0.3 million of variable leases costs are included in Selling, general and administrative for the three and nine months ended September 30, 2021, respectively, and zero and $0.2 million for the three and nine months ended September 30, 2020 respectively. These variable costs consist of the Company's proportionate share of operating expenses, real estate taxes and utilities. (b) Finance lease costs recorded in cost of revenue include variable lease costs of $0.7 million and $2.0 million for the three and nine months ended September 30, 2021 , respectively, and $0.6 million and $1.8 million for the three and nine months ended September 30, 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 for the three and nine months ended September 30, 2021 and 2020 . Future minimum commitments for finance and operating leases that have non-cancelable lease terms in excess of one year as of September 30, 2021 were as follows: Year ending (in thousands): Finance Operating Remainder of 2021 $ 718 $ 1,242 2022 2,539 4,624 2023 1,544 3,516 2024 733 2,917 2025 169 2,409 Thereafter — 4,043 Total minimum lease payments $ 5,703 $ 18,751 Amounts representing interest (365) Present value of net minimum lease payments $ 5,338 The following is a summary of the lease terms and discount rates: September 30, 2021 December 31, 2020 Weighted average lease term (in years): Operating 4.99 5.48 Finance 2.48 2.78 Weighted average discount rate: Operating 4.84 % 4.83 % Finance 5.37 % 5.50 % The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Nine months ended September 30, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,696 $ 3,963 Operating cash flows from finance leases 236 269 Financing cash flows from finance leases 1,966 1,966 Right-of-use assets exchanged for lease liabilities: Operating leases $ 156 924 Finance leases 846 2,399 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 47 586 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — (64)

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 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 condensed consolidated financial statements. In the opinion of the Company’s management, 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, filed a Demand for Arbitration in the state of Michigan against the Company's wholly-owned subsidiary, Limbach Company LLC. The demand seeks 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. 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., filed a complaint against Limbach Holdings, Inc. in Superior Court of the State of California for the County of Los Angeles against Limbach Holdings, Inc. 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. Trial is currently expected to take place in February 2022. As of September 30, 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, as well as seeks to enforce payment obligations under payment and stop notice release bonds. The Company disputes the allegations and intends to vigorously defend the suit, which is currently set for trial in May of 2022. As of September 30, 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. 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 September 30, 2021, the Company had approximately $230.7 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 September 30, 2021 and December 31, 2020 are as follows: (in thousands) September 30, December 31, Current liability — workers’ compensation and general liability $ 94 $ 197 Current liability — medical and dental 540 764 Non-current liability 776 890 Total liability shown in Accrued expenses and other current liabilities $ 1,410 $ 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.

Management Incentive Plans

Management Incentive Plans	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Management Incentive Plans	Management Incentive Plans The 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 provides that the Company may grant options, stock appreciation rights, restricted shares, restricted stock units, 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 further amendment and restatement of the Omnibus Incentive Plan upon approval of the Company's stockholders on June 16, 2021, the Company has reserved a total of 2,250,000 shares of its common stock for issuance under the Omnibus Incentive Plan. See Note 6 for a further description of the Omnibus Incentive 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 During the first nine months of 2021, the Company granted 123,407 service-based RSUs to its executives, certain employees, and non-employee directors under the Omnibus Incentive Plan. The following table summarizes the Company's service-based RSU activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 285,799 $ 6.32 Granted 123,407 12.17 Vested (112,784) 6.76 Forfeited (2,333) 8.27 Unvested at September 30, 2021 294,089 $ 8.59 Performance-Based Awards During the first nine months of 2021, the Company granted 185,367 performance-based RSUs (“PRSUs”) to its executives and certain employees under the Omnibus Incentive Plan. The Company will recognize stock-based compensation expense for these awards over the vesting period based on the projected probability of achievement of certain 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. For the three and nine months ended September 30, 2021, the Company recognized $0.2 million and $0.6 million, respectively, of stock-based compensation expense related to outstanding PRSUs. For the three and nine months ended September 30, 2020, the Company recognized $0.1 million of stock-based compensation expense related to outstanding PRSUs, respectively. The following table summarizes the Company's PRSU activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 99,500 $ 4.23 Granted 185,367 12.26 Vested — — Forfeited (4,167) 8.92 Unvested at September 30, 2021 280,700 $ 9.46 Market-Based Awards On September 4, 2020, the Compensation Committee (the “Committee”) of the Board of Directors of the Company approved amendments to certain restricted stock units 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 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 the Company's market-based RSU (“MRSUs”) activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 102,500 $ 8.26 Granted — — Vested — — Forfeited — — Unvested at September 30, 2021 102,500 $ 8.26 Total recognized stock-based compensation expense amounted to $0.7 million and $2.0 million for the three and nine months ended September 30, 2021, respectively, and $0.3 million and $0.7 million for the three and nine months ended September 30, 2020, respectively. The aggregate fair value as of the vest date of RSUs that vested during the nine months ended September 30, 2021 and 2020 was $1.4 million and $0.6 million, respectively. Total unrecognized stock-based compensation expense related to unvested RSUs which are probable of vesting was $2.9 million at September 30, 2021. These costs are expected to be recognized over a weighted average period of 1.87 years.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation 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, and Harper Limbach Construction LLC for all periods presented. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) for interim financial information and with the requirements of Form 10-Q and Rule 8-03 of Regulation S-X for smaller reporting companies. Consequently, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading. Readers of this report should refer to the consolidated financial statements and the notes thereto included in the Company's most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 25, 2021.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheets, Condensed Consolidated Statements of Operations, Condensed Consolidated Statements of Stockholders’ Equity and Condensed Consolidated Statements of Cash Flows for the periods presented are unaudited. Also, within the notes to the condensed consolidated financial statements, the Company has included unaudited information for these interim periods. These unaudited interim condensed consolidated financial statements have been prepared in accordance with GAAP. In the Company's opinion, the accompanying unaudited condensed consolidated financial statements contain all normal and recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2021, its results of operations and its cash flows for the three and nine months ended September 30, 2021. The results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021. The Condensed Consolidated Balance Sheet as of December 31, 2020 was derived from the Company's audited financial statements included in its Annual Report on Form 10-K filed with the SEC on March 25, 2021, but is presented as condensed and does not contain all of the footnote disclosures from the annual financial statements.
Recently Adopted Accounting Standards and Recent Accounting Pronouncements	Recently Adopted Accounting Standards 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 condensed 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 condensed 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 condensed consolidated financial statements. Management has identified that its credit agreement utilizes LIBOR as a benchmark rate. Management will continue to evaluate the impact of adopting reference rate reform as the LIBOR benchmark rate within the credit agreement is phased out. 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 condensed consolidated financial statements.
Revenue from Contract with Customers	Revenue from Contracts with Customers The 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. 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. Billings in excess of costs and estimated earnings 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 condensed 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. 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.
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.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Components of Contract Asset and Liability Balances	Contract assets include costs in excess of billings and estimated earnings and amounts due under retainage provisions. The components of the contract asset balances as of the respective dates were as follows: (in thousands) September 30, 2021 December 31, 2020 Change Contract assets Costs in excess of billings and estimated earnings $ 39,772 $ 31,894 $ 7,878 Retainage receivable 32,421 35,204 (2,783) Total contract assets $ 72,193 $ 67,098 $ 5,095 Contract liabilities include billings in excess of costs and estimated earnings and provisions for losses. The components of the contract liability balances as of the respective dates were as follows: (in thousands) September 30, 2021 December 31, 2020 Change Contract liabilities Billings in excess of costs and estimated earnings $ 36,517 $ 46,020 $ (9,503) Provisions for losses 486 628 (142) Total contract liabilities $ 37,003 $ 46,648 $ (9,645)
Schedule of Contracts In Progress	The net overbilling position for contracts in process consist of the following: (in thousands) September 30, 2021 December 31, 2020 Revenue earned on uncompleted contracts $ 718,366 $ 752,564 Less: Billings to date (715,111) (766,690) Net underbilling (overbilling) $ 3,255 $ (14,126) (in thousands) September 30, 2021 December 31, 2020 Costs in excess of billings and estimated earnings $ 39,772 $ 31,894 Billings in excess of costs and estimated earnings (36,517) (46,020) Net underbilling (overbilling) $ 3,255 $ (14,126)

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets are comprised of the following: (in thousands) Gross Accumulated Net intangible September 30, 2021 (1) Amortized intangible assets: Customer relationships – ODR $ 4,710 $ (3,396) $ 1,314 Favorable leasehold interests (2) 190 (78) 112 Total amortized intangible assets 4,900 (3,474) 1,426 Unamortized intangible assets: Trade name 9,960 — 9,960 Total unamortized intangible assets 9,960 — 9,960 Total amortized and unamortized assets, excluding goodwill $ 14,860 $ (3,474) $ 11,386 (in thousands) Gross Accumulated Net intangible December 31, 2020 (1) Amortized intangible assets: Customer relationships – ODR $ 4,710 $ (3,112) $ 1,598 Favorable leasehold interests 530 (407) 123 Total amortized intangible assets 5,240 (3,519) 1,721 Unamortized intangible assets: Trade name 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-Construction 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. (2) 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.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	Long-term debt consists of the following obligations as of: (in thousands) September 30, 2021 December 31, 2020 2019 Refinancing Term Loan - term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022 $ — $ 39,000 2019 Revolving Credit Facility — — Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in March 2021) plus interest through February 2026 26,500 — Wintrust Revolving Loan — — Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.70% to 6.45% through 2025 5,338 6,459 Total debt 31,838 45,459 Less - Current portion of long-term debt (8,460) (6,536) Less - Unamortized discount and debt issuance costs (284) (2,410) Long-term debt $ 23,094 $ 36,513
Schedule of Additional Margin and Commitment Fees Payable	The following is a summary of the additional margin and commitment fees payable on the available Wintrust Term Loan and Wintrust Revolving Loan credit commitment: Level Senior Leverage Ratio Additional Margin for Additional Margin for Additional Margin for Eurodollar Term loans Additional Margin for Eurodollar Revolving loans Commitment Fee I Greater than 1.00 to 1.00 1.00 % 0.50 % 4.00 % 3.50 % 0.25 % II Less than or equal to 1.00 to 1.00 0.25 % — % 3.50 % 3.00 % 0.25 %

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Outstanding Warrants	September 30, 2021 December 31, 2020 Public Warrants (1)(6) — 2,300,000 Private Warrants (2)(6) — 99,000 $15 Exercise Price Sponsor 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 share 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.

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 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 shareholders for the three and nine months ended September 30, 2021 and 2020: Three months ended September 30, Nine Months Ended (in thousands, except per share amounts) 2021 2020 2021 2020 EPS numerator: Net income $ 3,986 $ 2,525 $ 2,436 $ 5,420 EPS denominator: Weighted average shares outstanding – basic 10,266 7,890 9,916 7,845 Impact of dilutive securities 226 217 229 125 Weighted average shares outstanding – diluted 10,492 8,107 10,145 7,970 EPS: Basic $ 0.39 $ 0.32 $ 0.25 $ 0.69 Diluted (1) $ 0.38 $ 0.31 $ 0.24 $ 0.68 (1) Diluted EPS assumes the dilutive effect of outstanding common stock warrants and RSUs using the treasury stock method .
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: Three months ended September 30, Nine Months Ended 2021 2020 2021 2020 Out-of-the-money warrants (see Note 6) (1) 1,885,202 4,576,799 3,571,833 4,576,799 Service-based RSUs (See Note 13) 290 — 155 538 Performance and market-based RSUs (2) 36,305 — 8,707 — Employee Stock Purchase Plan — 8,375 — 4,375 Total 1,921,797 4,585,174 3,580,695 4,581,712 (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 three and nine months ended September 30, 2021 and 2020, certain PRSU and MRSU awards (each defined in Note 13) 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.

Operating Segments (Tables)

Operating Segments (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Condensed Consolidated Segment Information	Condensed consolidated segment information for the three and nine months ended September 30, 2021 and 2020 were as follows: Three months ended September 30, Nine Months Ended (in thousands) 2021 2020 2021 2020 Statement of Operations Data: Revenue: GCR $ 89,950 $ 130,498 $ 262,304 $ 345,921 ODR 39,227 33,358 101,236 91,892 Total revenue 129,177 163,856 363,540 437,813 Gross profit: GCR 12,754 14,848 31,034 38,043 ODR 11,709 9,323 29,348 24,687 Total gross profit 24,463 24,171 60,382 62,730 Selling, general and administrative: GCR 9,586 10,501 27,770 28,700 ODR 8,013 6,240 22,893 18,157 Corporate 703 304 2,016 739 Total selling, general and administrative 18,302 17,045 52,679 47,596 Amortization of intangibles 87 109 295 526 Operating income $ 6,074 $ 7,017 $ 7,408 $ 14,608 Less unallocated amounts: Interest expense, net (424) (2,154) (2,140) (6,449) Loss on early debt extinguishment — — (1,961) — (Loss) gain on disposition of property and equipment (49) 3 (41) 18 (Loss) gain on change in fair value of warrant liability — (1,371) 14 (1,312) Total unallocated amounts (473) (3,522) (4,128) (7,743) Income before income taxes $ 5,601 $ 3,495 $ 3,280 $ 6,865 Other Data: Depreciation and amortization: GCR $ 1,035 $ 1,046 $ 3,091 $ 3,108 ODR 267 340 967 1,001 Corporate 87 109 295 526 Total other data $ 1,389 $ 1,495 $ 4,353 $ 4,635

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Supplemental Balance Sheets Information	The following table summarizes the lease amounts included in the Company's condensed consolidated balance sheets: (in thousands) Classification on the Condensed Consolidated Balance Sheets September 30, 2021 December 31, 2020 Assets Operating Operating lease right-of-use assets (a) $ 15,802 $ 18,751 Finance Property and equipment, net (b) 5,116 6,242 Total lease assets $ 20,918 $ 24,993 Liabilities Current Operating Current operating lease liabilities $ 4,061 $ 3,929 Finance Current portion of long-term debt 2,460 2,536 Noncurrent Operating Long-term operating lease liabilities 12,495 15,459 Finance Long-term debt 2,878 3,923 Total lease liabilities $ 21,894 $ 25,847 (a) Operating lease assets are recorded net of accumulated amortization of $15.0 million at September 30, 2021 and $11.9 million at December 31, 2020. (b) Finance lease assets are recorded net of accumulated amortization of $5.8 million at September 30, 2021 and $5.3 million at December 31, 2020.
Summary of Lease Costs, Lease Terms and Discount Rates	The following table summarizes the lease costs included in the Company's condensed consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020: Three Months Ended Nine Months Ended (in thousands) Classification on the Condensed Consolidated Statement of Operations 2021 2020 2021 2020 Operating lease cost Cost of revenue (a) $ 716 $ 882 $ 2,088 $ 2,658 Operating lease cost Selling, general and administrative (a) 553 355 1,724 1,110 Finance lease cost Amortization Cost of revenue (b) 644 684 1,971 2,001 Interest Interest expense, net (b) 72 89 236 269 Total lease cost $ 1,985 $ 2,010 $ 6,019 $ 6,038 (a) Operating lease costs recorded in cost of sales includes $0.2 million and $0.4 million of variable lease costs for the three and nine months ended September 30, 2021, respectively, and $0.2 million and $0.5 million for the three and nine months ended September 30, 2020, respectively. In addition, $0.1 million and $0.3 million of variable leases costs are included in Selling, general and administrative for the three and nine months ended September 30, 2021, respectively, and zero and $0.2 million for the three and nine months ended September 30, 2020 respectively. These variable costs consist of the Company's proportionate share of operating expenses, real estate taxes and utilities. (b) Finance lease costs recorded in cost of revenue include variable lease costs of $0.7 million and $2.0 million for the three and nine months ended September 30, 2021 , respectively, and $0.6 million and $1.8 million for the three and nine months ended September 30, 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 for the three and nine months ended September 30, 2021 and 2020 . The following is a summary of the lease terms and discount rates: September 30, 2021 December 31, 2020 Weighted average lease term (in years): Operating 4.99 5.48 Finance 2.48 2.78 Weighted average discount rate: Operating 4.84 % 4.83 % Finance 5.37 % 5.50 %
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 September 30, 2021 were as follows: Year ending (in thousands): Finance Operating Remainder of 2021 $ 718 $ 1,242 2022 2,539 4,624 2023 1,544 3,516 2024 733 2,917 2025 169 2,409 Thereafter — 4,043 Total minimum lease payments $ 5,703 $ 18,751 Amounts representing interest (365) Present value of net minimum lease payments $ 5,338
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 September 30, 2021 were as follows: Year ending (in thousands): Finance Operating Remainder of 2021 $ 718 $ 1,242 2022 2,539 4,624 2023 1,544 3,516 2024 733 2,917 2025 169 2,409 Thereafter — 4,043 Total minimum lease payments $ 5,703 $ 18,751 Amounts representing interest (365) Present value of net minimum lease payments $ 5,338
Leases Supplemental Cash Flow Information	The following is a summary of other information and supplemental cash flow information related to finance and operating leases: Nine months ended September 30, (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,696 $ 3,963 Operating cash flows from finance leases 236 269 Financing cash flows from finance leases 1,966 1,966 Right-of-use assets exchanged for lease liabilities: Operating leases $ 156 924 Finance leases 846 2,399 Right-of-use assets disposed or adjusted modifying operating leases liabilities $ 47 586 Right-of-use assets disposed or adjusted modifying finance leases liabilities $ — (64)

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Components of Self-Insurance	The components of the self-insurance liability as of September 30, 2021 and December 31, 2020 are as follows: (in thousands) September 30, December 31, Current liability — workers’ compensation and general liability $ 94 $ 197 Current liability — medical and dental 540 764 Non-current liability 776 890 Total liability shown in Accrued expenses and other current liabilities $ 1,410 $ 1,851 Restricted cash $ 113 $ 113

Management Incentive Plans (Tab

Management Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2021
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested Restricted Stock Units Activity	The following table summarizes the Company's service-based RSU activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 285,799 $ 6.32 Granted 123,407 12.17 Vested (112,784) 6.76 Forfeited (2,333) 8.27 Unvested at September 30, 2021 294,089 $ 8.59
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested Restricted Stock Units Activity	The following table summarizes the Company's PRSU activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 99,500 $ 4.23 Granted 185,367 12.26 Vested — — Forfeited (4,167) 8.92 Unvested at September 30, 2021 280,700 $ 9.46
MRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested Restricted Stock Units Activity	The following table summarizes the Company's market-based RSU (“MRSUs”) activity for the nine months ended September 30, 2021: Awards Weighted-Average Unvested at December 31, 2020 102,500 $ 8.26 Granted — — Vested — — Forfeited — — Unvested at September 30, 2021 102,500 $ 8.26

Business and Organization (Deta

Business and Organization (Details)	9 Months Ended
	Sep. 30, 2021approachsegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | segment	2
Number distinct approaches to customer base | approach	2
Service period	2 years

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Components of Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Contract assets
Costs in excess of billings and estimated earnings	$ 39,772		$ 31,894
Retainage receivable	32,421		35,204
Total contract assets	72,193		67,098
Change in costs in excess of billings and estimated earnings	7,878
Change in retainage receivable	(2,783)
Change in contract assets	5,095	$ (8,612)
Contract liabilities
Billings in excess of costs and estimated earnings	36,517		46,020
Provisions for losses	486		628
Total contract liabilities	37,003		$ 46,648
Change in billings in excess of costs and estimated earnings	(9,503)
Change in provisions for losses	(142)
Change in contract liabilities	$ (9,645)	$ 18,715

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)project	Sep. 30, 2020USD ($)project	Sep. 30, 2021USD ($)project	Sep. 30, 2020USD ($)project	Dec. 31, 2020USD ($)
Property, Plant and Equipment [Line Items]
Duration period of contracts with customers			six months to two years
Percentage completed of certain milestones			10.00%
Net realizable value of unapproved orders	$ 39,200		$ 39,200		$ 33,600
Gross profit write downs	1,200	$ 800	1,300	$ 4,200
Revision amount for gross profit impact on contract estimates (more than)	250		250
GCR
Property, Plant and Equipment [Line Items]
Gross profit write downs	$ 1,400	$ 2,400	$ 5,300	$ 7,500
Number of projects subject to gross profit write downs | project	3	5	9	11
Number of projects subject to gross profit write ups | project	3			3
Gross profit write ups	$ 1,200		$ 2,900	$ 1,600
GCR | New England Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs	$ 600		$ 700
Number of projects subject to gross profit write downs | project	1		1
Number of projects subject to gross profit write ups | project	1		1
Gross profit write ups	$ 600		$ 400
GCR | Southern California Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs	$ 800	$ 1,800	$ 1,800
Number of projects subject to gross profit write downs | project	2	3	3
Number of projects subject to gross profit write ups | project		1	7
Gross profit write ups		$ 400
GCR | Florida Region Project
Property, Plant and Equipment [Line Items]
Number of projects subject to gross profit write ups | project	2		2
Gross profit write ups	$ 600		$ 900
GCR | Michigan Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs			$ 1,300
Number of projects subject to gross profit write downs | project			2
Number of projects subject to gross profit write ups | project			1
Gross profit write ups			$ 700
GCR | Eastern Pennsylvania Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs			$ 1,200
Number of projects subject to gross profit write downs | project			2
GCR | Mid-Atlantic Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs			$ 300
Number of projects subject to gross profit write downs | project			1
Number of projects subject to gross profit write ups | project			1
Gross profit write ups			$ 300
GCR | Ohio Region Project
Property, Plant and Equipment [Line Items]
Number of projects subject to gross profit write ups | project			2
Gross profit write ups			$ 600
ODR
Property, Plant and Equipment [Line Items]
Gross profit write downs			$ 300
Number of projects subject to gross profit write downs | project			1
ODR | Eastern Pennsylvania Region Project
Property, Plant and Equipment [Line Items]
Gross profit write downs			$ 300
Number of projects subject to gross profit write downs | project			1

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contracts In Progress (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue earned on uncompleted contracts	$ 718,366	$ 752,564
Less: Billings to date	(715,111)	(766,690)
Net underbilling (overbilling)	3,255	(14,126)
Costs in excess of billings and estimated earnings	39,772	31,894
Billings in excess of costs and estimated earnings	$ (36,517)	$ (46,020)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Remaining Performance Obligations (Details) $ in Millions	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligations, expected timing of satisfaction, period	24 months
GCR
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, amount	$ 345.5
GCR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligations, percentage	25.00%
Revenue, remaining performance obligations, expected timing of satisfaction, period	3 months
GCR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligations, percentage	56.00%
Revenue, remaining performance obligations, expected timing of satisfaction, period	1 year 9 months
ODR
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, amount	$ 52.8
ODR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligations, percentage	37.00%
Revenue, remaining performance obligations, expected timing of satisfaction, period	3 months
ODR | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligations, percentage	38.00%
Revenue, remaining performance obligations, expected timing of satisfaction, period	1 year 9 months

Goodwill and Intangibles - Narr

Goodwill and Intangibles - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 6,129,000		$ 6,129,000		$ 6,129,000
Impairment of goodwill	0	$ 0	0	$ 0
Amortization of intangibles	87,000	109,000	295,000	526,000
Impairment of intangible assets (excluding goodwill)	0	$ 0	0	$ 0
Trade name
Goodwill [Line Items]
Amount of excess of fair value over carrying amount of indefinite-lived intangible assets	$ 1,000,000		$ 1,000,000
Percentage of fair value in excess of carrying amount of indefinite-lived intangibles assets	0.10		0.10
OD Reporting Unit
Goodwill [Line Items]
Amount of fair value in excess of carrying amount of reporting unit	$ 33,300,000		$ 33,300,000
Percentage of fair value in excess of carrying amount of reporting unit	169.00%		169.00%
Impairment of goodwill	$ 0		$ 0

Goodwill and Intangibles - Inta

Goodwill and Intangibles - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Amortized intangible assets:
Gross carrying amount		$ 4,900	$ 5,240
Accumulated amortization		(3,474)	(3,519)
Net intangible assets, excluding goodwill		1,426	1,721
Unamortized intangible assets:
Gross carrying amount		9,960	9,960
Net intangible assets, excluding goodwill		9,960	9,960
Gross carrying amount		14,860	15,200
Accumulated amortization		(3,474)	(3,519)
Total amortized and unamortized assets, excluding goodwill		11,386	11,681
Trade name
Unamortized intangible assets:
Gross carrying amount		9,960	9,960
Net intangible assets, excluding goodwill		9,960	9,960
Customer Relationships | ODR
Amortized intangible assets:
Gross carrying amount		4,710	4,710
Accumulated amortization		(3,396)	(3,112)
Net intangible assets, excluding goodwill		1,314	1,598
Unamortized intangible assets:
Accumulated amortization		(3,396)	(3,112)
Favorable Leasehold Interests
Amortized intangible assets:
Gross carrying amount		190	530
Accumulated amortization		(78)	(407)
Net intangible assets, excluding goodwill		112	123
Unamortized intangible assets:
Accumulated amortization		$ (78)	(407)
Reduction in gross carrying amount and accumulated amortization of intangibles due to lease termination	$ 300
Backlog – Construction
Amortized intangible assets:
Gross carrying amount			4,800
Accumulated amortization			(4,800)
Unamortized intangible assets:
Accumulated amortization			$ (4,800)

Debt - Long-Term Debt (Details)

Debt - Long-Term Debt (Details) - USD ($) $ in Thousands	Feb. 24, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Finance leases – collateralized by vehicles, payable in monthly installments of principal, plus interest ranging from 4.70% to 6.45% through 2025		$ 5,338		$ 5,338		$ 6,459
Total debt		31,838		31,838		45,459
Less - Current portion of long-term debt		(8,460)		(8,460)		(6,536)
Less - Unamortized discount and debt issuance costs		(284)		(284)		(2,410)
Long-term debt		23,094		23,094		36,513
Loss on early debt extinguishment		$ 0	$ 0	1,961	$ 0
Prepayment penalty and other costs associated with early debt extinguishment				$ 1,376	$ 0
Minimum
Debt Instrument [Line Items]
Finance lease, discount rate		4.70%		4.70%
Maximum
Debt Instrument [Line Items]
Finance lease, discount rate		6.45%		6.45%
2019 Refinancing Agreement
Debt Instrument [Line Items]
Loss on early debt extinguishment	$ 2,000
Write off of debt issuance and discount costs	2,600
Reversal or warrant liability	2,000
Prepayment penalty and other costs associated with early debt extinguishment	$ 1,400
Secured Debt | 2019 Refinancing Term Loan - term loan payable in quarterly installments of principal, (commencing in September 2020) plus interest through April 2022
Debt Instrument [Line Items]
Long term debt		$ 0		$ 0		39,000
Secured Debt | Wintrust Term Loan - term loan payable in quarterly installments of principal, (commencing in March 2021) plus interest through February 2026
Debt Instrument [Line Items]
Long term debt		26,500		26,500		0
Revolving Credit Facility | 2019 Revolving Credit Facility
Debt Instrument [Line Items]
Long term debt		0		0		0
Revolving Credit Facility | Wintrust Revolving Loan
Debt Instrument [Line Items]
Long term debt		$ 0		$ 0		$ 0

Debt - 2019 Refinancing Agreeme

Debt - 2019 Refinancing Agreement - 2019 Term Loans (Details) - 2019 Refinancing Agreement - USD ($)	Apr. 12, 2019	Feb. 24, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Debt issued	$ 40,000,000
Debt installment payments	$ 1,000,000
Unused line fee percentage	2.00%
Make-whole premium prepayment period	19 months
Make-whole provision applicable to interest period	18 months
Debt effective interest rate		13.00%	13.00%
LIBOR Rate
Debt Instrument [Line Items]
Basis spread on variable rate	11.00%
LIBOR Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	10.00%
Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on 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	Sep. 30, 2021	Feb. 24, 2021	Dec. 31, 2020
2019 Refinancing Term Loan - CB Warrants
Debt Instrument [Line Items]
Class of warrant or right, number of securities called by each warrant or right (in shares)	263,314		0
Exercise price of warrants (in usd per share)	$ 7.63
Percentage of number of shares	2.00%
Debt outstanding			$ 0
2019 Refinancing Agreement
Debt Instrument [Line Items]
Warrants tem	5 years
Warrants liability	$ 900,000	$ 0	$ 2,000,000	$ 2,000,000
Derivative liability	$ 400,000

Debt - 2019 ABL Credit Agreemen

Debt - 2019 ABL Credit Agreement (Details) - 2019 Refinancing Revolving Credit Facility - USD ($)	Nov. 14, 2019	Feb. 24, 2021	Dec. 31, 2020	Sep. 30, 2020	Apr. 12, 2019
Debt Instrument [Line Items]
Debt effective interest rate		5.25%		5.25%
Letters of credit		$ 3,400,000	$ 3,400,000
LIBOR Rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
LIBOR Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
LIBOR Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	3.50%
Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					$ 15,000,000

Debt - Wintrust Term and Revolv

Debt - Wintrust Term and Revolving Loans (Details)	Feb. 24, 2021USD ($)covenant	Sep. 30, 2021USD ($)
Wintrust Loans
Debt Instrument [Line Items]
Aggregate amount of unfinanced capital expenditures during any fiscal year	$ 0
Limit annual percentage of unfinanced capital expenditures	50.00%
Letters of credit		$ 3,400,000
Wintrust Loans | Through December 31, 2021
Debt Instrument [Line Items]
Number of financial covenants | covenant	3
Leverage ratio	225.00%
Wintrust Loans | All times thereafter
Debt Instrument [Line Items]
Leverage ratio	200.00%
Wintrust Loans | As of the last day of each fiscal quarter commencing with the fiscal quarter ending March 31, 2021
Debt Instrument [Line Items]
Leverage ratio	120.00%
Wintrust Loans | Maximum
Debt Instrument [Line Items]
Aggregate amount of unfinanced capital expenditures during any fiscal year	$ 4,000,000
Wintrust Term Loan
Debt Instrument [Line Items]
Debt effective interest rate		4.25%
Wintrust Revolving Loan
Debt Instrument [Line Items]
Debt effective interest rate		3.75%
Secured Debt | Wintrust Term Loan
Debt Instrument [Line Items]
Debt issued	30,000,000
Debt installment payments	$ 500,000
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR Rate
Debt Instrument [Line Items]
Step-down adjustment on basis spread on variable rate	0.50%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | LIBOR Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	4.00%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate
Debt Instrument [Line Items]
Step-down adjustment on basis spread on variable rate	0.75%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
Line of Credit | Revolving Credit Facility | Wintrust Term Loan | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 25,000,000
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | LIBOR Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | LIBOR Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	3.50%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate
Debt Instrument [Line Items]
Step-down adjustment on basis spread on variable rate	0.50%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
Line of Credit | Revolving Credit Facility | Wintrust Revolving Loan | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Line of Credit | Sublimit for Letters of Credit | Wintrust Revolving Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 5,000,000

Debt - Additional Margin and Co

Debt - Additional Margin and Commitment Fees Payable (Details)	9 Months Ended
	Sep. 30, 2021
Level I
Debt Instrument [Line Items]
Senior Leverage Ratio	100.00%
Commitment Fee	0.25%
Level I | Prime Rate | Wintrust Term Loan
Debt Instrument [Line Items]
Additional Margin for Loans	1.00%
Level I | Prime Rate | Wintrust Revolving Loan
Debt Instrument [Line Items]
Additional Margin for Loans	0.50%
Level I | Eurodollar | Wintrust Term Loan
Debt Instrument [Line Items]
Additional Margin for Loans	4.00%
Level I | Eurodollar | Wintrust Revolving Loan
Debt Instrument [Line Items]
Additional Margin for Loans	3.50%
Level II
Debt Instrument [Line Items]
Senior Leverage Ratio	100.00%
Commitment Fee	0.25%
Level II | Prime Rate | Wintrust Term Loan
Debt Instrument [Line Items]
Additional Margin for Loans	0.25%
Level II | Prime Rate | Wintrust Revolving Loan
Debt Instrument [Line Items]
Additional Margin for Loans	0.00%
Level II | Eurodollar | Wintrust Term Loan
Debt Instrument [Line Items]
Additional Margin for Loans	3.50%
Level II | Eurodollar | Wintrust Revolving Loan
Debt Instrument [Line Items]
Additional Margin for Loans	3.00%

Equity - Narrative (Details)

Equity - Narrative (Details) - USD ($)	Mar. 09, 2021	Feb. 18, 2021	Feb. 12, 2021	May 24, 2020	Jan. 01, 2020	Jul. 31, 2021	Jan. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020
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
Preferred stock, shares authorized (in shares)									1,000,000
Preferred stock, par or stated value per share (in usd per shares)									$ 0.0001
2021 Public Offering
Class of Stock [Line Items]
Number of shares sold (in shares)			1,783,500
Share price (in usd per share)			$ 12
Proceeds from sale of shares, net of underwriters discounts and commissions			$ 19,800,000
Over-allotment Option
Class of Stock [Line Items]
Number of shares sold (in shares)			267,525
Share 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 2019
Class of Stock [Line Items]
Number of additional shares authorized under share-based compensation plan (in shares)	600,000			500,000
Common stock, capital shares reserved for future issuance (in shares)	2,250,000			1,650,000
ESPP | Employee Stock
Class of Stock [Line Items]
Purchase price of common stock, percent of market price (no less than)					85.00%
Maximum employee subscription percentage					10.00%
Maximum contribution amount					$ 5,000
Offering period					6 months
Discount percentage from market price, beginning of purchase period					15.00%
Award vesting period					6 months
Number of shares authorized (in shares)					500,000
Shares issued (in shares)						16,140	8,928	39,753
Shares remaining available for future issuance (in shares)									444,107
$15 Exercise Price Sponsor Warrants
Class of Stock [Line Items]
Exercise price of warrants (in usd per share)									$ 15	$ 15

Equity - Outstanding Warrants (

Equity - Outstanding Warrants (Details) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	1,229,643	4,576,799
Public Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	0	2,300,000
Class of warrant or right, number of securities called by each warrant or right (in shares)	0.50	0.50
Class of warrant or right, rights for half share (in usd per share)	$ 5.75	$ 5.75
Exercise price of warrants (in usd per share)	$ 11.50	$ 11.50
Private Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	0	99,000
Class of warrant or right, number of securities called by each warrant or right (in shares)	0.50	0.50
Class of warrant or right, rights for half share (in usd per share)	$ 5.75	$ 5.75
Exercise price of warrants (in usd per share)	$ 11.50	$ 11.50
$15 Exercise Price Sponsor Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	600,000	600,000
Class of warrant or right, number of securities called by each warrant or right (in shares)	1	1
Exercise price of warrants (in usd per share)	$ 15	$ 15
Merger Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	629,643	631,119
Class of warrant or right, number of securities called by each warrant or right (in shares)	1	1
Exercise price of warrants (in usd per share)	$ 12.50	$ 12.50
Additional Merger Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)	0	946,680
Class of warrant or right, number of securities called by each warrant or right (in shares)	1	1
Exercise price of warrants (in usd per share)	$ 11.50	$ 11.50

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($)	2 Months Ended	3 Months Ended		9 Months Ended
	Feb. 24, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Apr. 12, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
(Gain) loss on change in fair value of warrant liability		$ 0	$ 1,371,000	$ (14,000)	$ 1,312,000
2019 Refinancing Agreement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrants liability	$ 2,000,000	0		0		$ 2,000,000	$ 900,000
(Gain) loss on change in fair value of warrant liability	(100,000)		$ 1,400,000		$ 1,300,000
Wintrust Revolving Loan | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 39,000,000					$ 39,000,000
Wintrust Term Loan | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt		$ 26,500,000		$ 26,500,000

Earnings per Share - Schedule o

Earnings per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
EPS numerator:
Net income	$ 3,986	$ 732	$ (2,282)	$ 2,525	$ 2,947	$ (52)	$ 2,436	$ 5,420
EPS denominator:
Weighted average shares outstanding - basic (in shares)	10,266,486			7,890,074			9,915,966	7,844,587
Impact of dilutive securities (in shares)	226,000			217,000			229,000	125,000
Weighted average shares outstanding - diluted (in shares)	10,491,863			8,107,149			10,145,470	7,969,857
EPS:
Basic (in usd per share)	$ 0.39			$ 0.32			$ 0.25	$ 0.69
Diluted (in usd per share)	$ 0.38			$ 0.31			$ 0.24	$ 0.68

Earnings per Share - Schedule_2

Earnings per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 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)	1,921,797	4,585,174	3,580,695	4,581,712
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)	1,885,202	4,576,799	3,571,833	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)	290	0	155	538
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)	36,305	0	8,707	0
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	8,375	0	4,375

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Effective tax rate	28.80%	27.80%	25.70%	21.10%
Valuation allowance	$ 0		$ 0		$ 0
Unrecognized tax benefits	$ 0		$ 0		$ 0

Operating Segments - Narrative

Operating Segments - Narrative (Details)	9 Months Ended
	Sep. 30, 2021approachsegment
Segment Reporting Information [Line Items]
Number of operating segments	2
Number distinct approaches to customer base | approach	2
GCR
Segment Reporting Information [Line Items]
Number of reportable segments	1
ODR
Segment Reporting Information [Line Items]
Number of reportable segments	1

Operating Segments - Condensed

Operating Segments - Condensed Consolidated Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenue	$ 129,177	$ 163,856	$ 363,540	$ 437,813
Gross profit	24,463	24,171	60,382	62,730
Selling, general and administrative	18,302	17,045	52,679	47,596
Amortization of intangibles	87	109	295	526
Operating income	6,074	7,017	7,408	14,608
Interest expense, net	(424)	(2,154)	(2,140)	(6,449)
Loss on early debt extinguishment	0	0	(1,961)	0
(Loss) gain on disposition of property and equipment	(49)	3	(41)	18
(Loss) gain on change in fair value of warrant liability	0	(1,371)	14	(1,312)
Total unallocated amounts	(473)	(3,522)	(4,128)	(7,743)
Income before income taxes	5,601	3,495	3,280	6,865
Depreciation and amortization	1,389	1,495	4,353	4,635
Operating Segments | GCR
Segment Reporting Information [Line Items]
Revenue	89,950	130,498	262,304	345,921
Gross profit	12,754	14,848	31,034	38,043
Selling, general and administrative	9,586	10,501	27,770	28,700
Depreciation and amortization	1,035	1,046	3,091	3,108
Operating Segments | ODR
Segment Reporting Information [Line Items]
Revenue	39,227	33,358	101,236	91,892
Gross profit	11,709	9,323	29,348	24,687
Selling, general and administrative	8,013	6,240	22,893	18,157
Depreciation and amortization	267	340	967	1,001
Corporate
Segment Reporting Information [Line Items]
Selling, general and administrative	703	304	2,016	739
Depreciation and amortization	$ 87	$ 109	$ 295	$ 526

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheets Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 15,802	$ 18,751
Property, plant and equipment, net	5,116	6,242
Lease right-of-use assets	20,918	24,993
Current operating lease liabilities	4,061	3,929
Current portion of long-term debt	2,460	2,536
Long-term operating lease liabilities	12,495	15,459
Long-term debt	2,878	3,923
Total lease liabilities	21,894	25,847
Operating lease, accumulated amortization	15,000	11,900
Finance lease, accumulated amortization	$ 5,800	$ 5,300

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Finance lease cost, amortization	$ 644,000	$ 684,000	$ 1,971,000	$ 2,001,000
Finance lease cost, interest expense	72,000	89,000	236,000	269,000
Total lease cost	1,985,000	2,010,000	6,019,000	6,038,000
Cost of revenue
Lessee, Lease, Description [Line Items]
Operating lease cost	716,000	882,000	2,088,000	2,658,000
Cost of revenue | Operating Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	200,000	200,000	400,000	500,000
Cost of revenue | Finance Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	700,000	600,000	2,000,000	1,800,000
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Operating lease cost	553,000	355,000	1,724,000	1,110,000
Selling, general and administrative expenses | Operating Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	100,000	0	300,000	200,000
Selling, general and administrative expenses | Finance Lease
Lessee, Lease, Description [Line Items]
Variable lease costs	$ 0	$ 0	$ 0	$ 0

Leases - Future Minimum Lease C

Leases - Future Minimum Lease Commitment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finance Leases
Remainder of 2021	$ 718
2022	2,539
2023	1,544
2024	733
2025	169
Thereafter	0
Total minimum lease payments	5,703
Amounts representing interest	(365)
Present value of net minimum lease payments	5,338	$ 6,459
Operating Leases
Remainder of 2021	1,242
2022	4,624
2023	3,516
2024	2,917
2025	2,409
Thereafter	4,043
Total minimum lease payments	$ 18,751

Leases - Summary of Lease Terms

Leases - Summary of Lease Terms and Discount Rates (Details)	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating leases, weighted average remaining lease term	4 years 11 months 26 days	5 years 5 months 23 days
Finance leases, weighted average remaining lease term	2 years 5 months 23 days	2 years 9 months 10 days
Operating leases, weighted average remaining discount rate	4.84%	4.83%
Finance leases, weighted average remaining discount rate	5.37%	5.50%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating cash flows from operating leases	$ 3,696	$ 3,963
Operating cash flows from finance leases	236	269
Financing cash flows from finance leases	1,966	1,966
Right of use assets obtained in exchange for new operating lease liabilities	156	924
Right of use assets obtained in exchange for new finance lease liabilities	846	2,399
Right-of-use assets disposed or adjusted modifying operating leases liabilities	47	586
Right-of-use assets disposed or adjusted modifying finance leases liabilities	$ 0	$ (64)

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	Apr. 17, 2020	Jan. 23, 2020	Nov. 13, 2019	Sep. 30, 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]
Debt outstanding				230,700,000
Lanzo Trenchless Technologies vs. Limbach Company LLC | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, damages sought, value			$ 400,000
Bernards Bros vs. Limbach Holdings, Inc. | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, damages sought, value		$ 3,000,000
LA Excavating, Inc. vs. Limbach Company LP | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 1,000,000
Loss contingency recorded				$ 0

Commitments and Contingencies_2

Commitments and Contingencies - Components of Self-Insurance Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Current liability — workers’ compensation and general liability	$ 94	$ 197
Current liability — medical and dental	540	764
Non-current liability	776	890
Total liability shown in Accrued expenses and other current liabilities	1,410	1,851
Restricted cash	$ 113	$ 113

Management Incentive Plans - Na

Management Incentive Plans - Narrative (Details) - USD ($) $ in Thousands	Sep. 04, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 09, 2021	May 24, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation				$ 2,016	$ 739
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				123,407
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				185,367
MRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				0
Unrecognized share-based costs	$ 200
Weighted average period to recognize share-based costs	1 year 3 months 3 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation		$ 700	$ 300	$ 2,000	700
Unrecognized share-based costs		2,900		$ 2,900
Weighted average period to recognize share-based costs				1 year 10 months 13 days
Fair value of awards vested				$ 1,400	600
Omnibus Incentive Plan 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)						2,250,000	1,650,000
Omnibus Incentive Plan 2019 | PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				185,367
Recognized stock-based compensation		$ 200	$ 100	$ 600	$ 100

Management Incentive Plans - RS

Management Incentive Plans - RSUs Activity (Details) - RSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Awards
Unvested at December 31, 2020 (in shares) | shares	285,799
Granted, awards (in shares) | shares	123,407
Vested, awards (in shares) | shares	(112,784)
Forfeited, awards (in shares) | shares	(2,333)
Unvested at September 30, 2021 (in shares) | shares	294,089
Weighted-Average Grant Date Fair Value
Unvested at December 31, 2020 (usd per share) | $ / shares	$ 6.32
Granted, weighted-average grant date fair values (usd per share) | $ / shares	12.17
Vested, weighted-average grant date fair values (usd per share) | $ / shares	6.76
Forfeited, weighted-average grant date fair values (usd per share) | $ / shares	8.27
Unvested at September 30, 2021 (usd per share) | $ / shares	$ 8.59

Management Incentive Plans - PR

Management Incentive Plans - PRSUs Activity (Details) - PRSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Awards
Unvested at December 31, 2020 (in shares) | shares	99,500
Granted, awards (in shares) | shares	185,367
Vested, awards (in shares) | shares	0
Forfeited, awards (in shares) | shares	(4,167)
Unvested at September 30, 2021 (in shares) | shares	280,700
Weighted-Average Grant Date Fair Value
Unvested at December 31, 2020 (usd per share) | $ / shares	$ 4.23
Granted, weighted-average grant date fair values (usd per share) | $ / shares	12.26
Vested, weighted-average grant date fair values (usd per share) | $ / shares	0
Forfeited, weighted-average grant date fair values (usd per share) | $ / shares	8.92
Unvested at September 30, 2021 (usd per share) | $ / shares	$ 9.46

Management Incentive Plans - MR

Management Incentive Plans - MRSUs Activity (Details) - MRSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Awards
Unvested at December 31, 2020 (in shares) | shares	102,500
Granted, awards (in shares) | shares	0
Vested, awards (in shares) | shares	0
Forfeited, awards (in shares) | shares	0
Unvested at September 30, 2021 (in shares) | shares	102,500
Weighted-Average Grant Date Fair Value
Unvested at December 31, 2020 (usd per share) | $ / shares	$ 8.26
Granted, weighted-average grant date fair values (usd per share) | $ / shares	0
Vested, weighted-average grant date fair values (usd per share) | $ / shares	0
Forfeited, weighted-average grant date fair values (usd per share) | $ / shares	0
Unvested at September 30, 2021 (usd per share) | $ / shares	$ 8.26