Mistras (MG) 10-Q 7 May 21 2021 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2021	May 03, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-34481
Entity Registrant Name	Mistras Group, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3341267
Entity Address, Address Line One	195 Clarksville Road
Entity Address, City or Town	Princeton Junction,
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08550
City Area Code	609
Local Phone Number	716-4000
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	MG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		29,431,913
Entity Central Index Key	0001436126
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 24,177	$ 25,760
Accounts receivable, net	111,960	107,628
Inventories	13,148	13,134
Prepaid expenses and other current assets	20,684	16,066
Total current assets	169,969	162,588
Property, plant and equipment, net	90,238	92,681
Intangible assets, net	66,222	68,642
Goodwill	206,660	206,008
Deferred income taxes	2,064	2,069
Other assets	49,248	51,325
Total assets	584,401	583,313
Current Liabilities
Accounts payable	15,052	14,240
Accrued expenses and other current liabilities	83,629	78,500
Current portion of long-term debt	11,145	10,678
Current portion of finance lease obligations	3,729	3,765
Income taxes payable	2,457	2,664
Total current liabilities	116,012	109,847
Long-term debt, net of current portion	211,161	209,538
Obligations under finance leases, net of current portion	10,635	11,115
Deferred income taxes	9,092	8,236
Other long-term liabilities	45,457	47,358
Total liabilities	392,357	386,094
Commitments and contingencies
Equity
Preferred stock, 10,000,000 shares authorized	0	0
Common stock, $0.01 par value, 200,000,000 shares authorized, 29,346,562 and 29,234,143 shares issued and outstanding	293	292
Additional paid-in capital	235,413	234,638
Accumulated deficit	(27,210)	(21,848)
Accumulated other comprehensive loss	(16,653)	(16,061)
Total Mistras Group, Inc. stockholders’ equity	191,843	197,021
Non-controlling interests	201	198
Total equity	192,044	197,219
Total liabilities and equity	$ 584,401	$ 583,313

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	29,346,562	29,234,143
Common stock, shares outstanding (in shares)	29,346,562	29,234,143

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Statements of Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 153,735	$ 159,465
Cost of revenue	108,243	113,324
Depreciation	5,491	5,497
Gross profit	40,001	40,644
Selling, general and administrative expenses	39,639	41,558
Impairment charges	0	106,062
Legal settlement and litigation charges, net	1,030	0
Research and engineering	727	824
Depreciation and amortization	3,074	3,970
Acquisition-related expense (benefit), net	277	(542)
Loss from operations	(4,746)	(111,228)
Interest expense	3,213	2,789
Loss before benefit for income taxes	(7,959)	(114,017)
Benefit for income taxes	(2,600)	(15,495)
Net Loss	(5,359)	(98,522)
Less: net income (loss) attributable to noncontrolling interests, net of taxes	3	(13)
Net loss attributable to Mistras Group, Inc.	$ (5,362)	$ (98,509)
Loss per common share
Basic (in dollars per share)	$ (0.18)	$ (3.40)
Diluted (in dollars per share)	$ (0.18)	$ (3.40)
Weighted-average common shares outstanding:
Basic (in shares)	29,425	28,963
Diluted (in shares)	29,425	28,963

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Loss	$ (5,359)	$ (98,522)
Other comprehensive loss:
Foreign currency translation adjustments	(592)	(17,015)
Comprehensive loss	(5,951)	(115,537)
Less: net income (loss) attributable to noncontrolling interests, net of taxes	3	(13)
Less: Foreign currency translation adjustments attributable to noncontrolling interests	0	(6)
Comprehensive loss attributable to Mistras Group, Inc.	$ (5,954)	$ (115,518)

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Mistras Group, Inc. Stockholders’ Equity	Common Stock	Additional paid-in capital	Retained earnings (deficit)	Accumulated other comprehensive loss	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2019			28,945
Beginning balance at Dec. 31, 2019	$ 286,022	$ 285,822	$ 289	$ 229,205	$ 77,613	$ (21,285)	$ 200
Increase (Decrease) in Stockholders' Equity
Net Loss	(98,522)	(98,509)			(98,509)		(13)
Other comprehensive loss, net of tax	(17,015)	(17,009)				(17,009)	(6)
Share-based payments	1,425	1,425		1,425
Net settlements of restricted stock units (in shares)			97
Net settlement of restricted stock units	(157)	(157)	$ 1	(158)
Ending balance (in shares) at Mar. 31, 2020			29,042
Ending balance at Mar. 31, 2020	171,753	171,572	$ 290	230,472	(20,896)	(38,294)	181
Beginning balance (in shares) at Dec. 31, 2020			29,234
Beginning balance at Dec. 31, 2020	197,219	197,021	$ 292	234,638	(21,848)	(16,061)	198
Increase (Decrease) in Stockholders' Equity
Net Loss	(5,359)	(5,362)			(5,362)		3
Other comprehensive loss, net of tax	(592)	(592)				(592)
Share-based payments	1,262	1,262		1,262
Net settlements of restricted stock units (in shares)			113
Net settlement of restricted stock units	(486)	(486)	$ 1	(487)
Ending balance (in shares) at Mar. 31, 2021			29,347
Ending balance at Mar. 31, 2021	$ 192,044	$ 191,843	$ 293	$ 235,413	$ (27,210)	$ (16,653)	$ 201

Unaudited Condensed Consolida_4

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities
Net Loss	$ (5,359)	$ (98,522)
Adjustments to reconcile net loss to net cash provided by operating activities
Depreciation and amortization	8,565	9,467
Impairment charges	0	106,062
Deferred income taxes	866	(13,739)
Share-based compensation expense	1,262	1,345
Fair value adjustments to contingent consideration	243	(542)
Foreign currency (gain) loss	455	307
Other	(48)	76
Changes in operating assets and liabilities, net of effect of acquisitions and dispositions
Accounts receivable	(5,417)	7,884
Inventories	(87)	(405)
Prepaid expenses and other assets	(4,944)	(985)
Accounts payable	942	(1,526)
Accrued expenses and other liabilities	6,881	(3,315)
Income taxes payable	(211)	0
Net cash provided by operating activities	3,148	6,107
Cash flows from investing activities
Purchase of property, plant and equipment	(4,003)	(4,301)
Purchase of intangible assets	(350)	(87)
Acquisition of business, net of cash acquired	(411)	0
Proceeds from sale of equipment	588	184
Net cash used in investing activities	(4,176)	(4,204)
Cash flows from financing activities
Repayment of finance lease obligations	(1,069)	(1,167)
Proceeds from borrowings of long-term debt	0	280
Repayment of long-term debt	(2,323)	(1,639)
Proceeds from revolver	23,000	13,500
Repayment of revolver	(17,750)	(8,500)
Payment of financing costs	0	(522)
Payment of contingent consideration for business acquisitions	(938)	(1,303)
Taxes paid related to net share settlement of share-based awards	(485)	(157)
Net cash provided by financing activities	435	492
Effect of exchange rate changes on cash and cash equivalents	(990)	(384)
Net change in cash and cash equivalents	(1,583)	2,011
Cash and cash equivalents at beginning of period	25,760	15,016
Cash and cash equivalents at end of period	24,177	17,027
Supplemental disclosure of cash paid
Interest, net	2,916	2,726
Income taxes, net of refunds	2,877	61
Noncash investing and financing
Equipment acquired through finance lease obligations	$ 643	$ 667

Description of Business_and Bas

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Description of Business Mistras Group, Inc. and subsidiaries (the Company) is a leading “OneSource™” multinational provider of integrated technology-enabled asset protection solutions helping to maximize the safety and operational uptime for civilization's most critical industrial and civil assets. Backed by an innovative, data-driven asset protection portfolio, proprietary technologies, and decades-long legacy of industry leadership, the Company helps clients in the oil and gas, aerospace and defense, power generation, civil infrastructure, and manufacturing industries towards achieving and maintaining operational excellence. By supporting these organizations that help fuel our vehicles and power our society; inspecting components that are trusted for commercial, defense, and space craft; and building real-time monitoring equipment to enable safe travel across bridges, the Company helps the world at large. The Company enhances value for its clients by integrating asset protection throughout supply chains and centralizing integrity data through a suite of Industrial IoT-connected digital software and monitoring solutions. The Company's core capabilities also include non-destructive testing (“NDT”) field inspections enhanced by advanced robotics, laboratory quality control and assurance testing, sensing technologies and NDT equipment, asset and mechanical integrity engineering services, and light mechanical maintenance and access services. The Company serves a global customer base of companies with asset-intensive infrastructure, including companies in the oil and gas, commercial aerospace and defense, fossil and nuclear power, alternative and renewable energy, public infrastructure, chemicals, transportation, primary metals and metalworking, pharmaceutical/biotechnology and food processing industries, and research and engineering institutions. Recent Developments The COVID-19 coronavirus (COVID-19) pandemic has caused significant volatility in domestic and international markets and is expected to continue to result in significant economic disruption. The Company's businesses have been classified as non-healthcare critical infrastructure as defined by the U.S. Centers for Disease Control and Prevention (CDC). As a result, a majority of the Company's customers have been and currently remain open for business. North American facilities have remained, and currently remain operating, with modified staffing in certain locations where appropriate. Similarly, our European facilities have remained, and currently remain operating, with modified staffing in certain locations where appropriate, but at a slower pace than North America. Overall, the Company has taken actions to ensure the health and safety of Company employees and those of its customers and suppliers; maintain business continuity and financial strength and stability; and serve customers as they provide essential products and services to the world. The COVID-19 pandemic, significant volatility in oil prices, and decreased traffic in the aerospace industry have adversely affected the operations of the Company's customers, suppliers and contractors, and as a consequence, the Company's results of operations. These negative factors have also resulted in significant volatility and uncertainty in the markets in which the Company operates. While the Company cannot fully assess the impact that the factors discussed above will have on its operations at this time, there were certain impacts that the Company identified resulting in impairment charges in 2020. See Note 8- Goodwill, Note 9- Intangible Assets and Note 13- Leases for additional information. To respond to the economic downturn resulting from the factors discussed above, in March 2020 the Company initiated a temporary cost reduction and efficiency program. The Company reinstated several of the temporary cost reductions initiatives undertaken during 2020; although, the Company continues to manage and evaluate these actions in responding to the pandemic. The Company is currently unable to predict with certainty the overall impact that the factors discussed above may have on its business, results of operations or liquidity or in other ways which the Company cannot yet determine. The Company will continue to monitor market conditions and respond accordingly. As of March 31, 2021, the cash balance was approximately $24.2 million. Basis of Presentation The Unaudited Condensed Consolidated Financial Statements contained in this report have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") and Securities and Exchange Commission guidance allowing for reduced disclosure for interim periods. In the opinion of management, the Unaudited Condensed Consolidated Financial Statements include all adjustments, which are of a normal recurring nature, necessary for a fair presentation of the results for the interim periods of the years ending December 31, 2021 and December 31, 2020. Certain items included in these statements are based on management’s estimates. Actual results may differ from those estimates. The results of operations for any interim period are not necessarily indicative of the results expected for the year. The accompanying Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the notes to the Audited Consolidated Financial Statements contained in the Company's 2020 Annual Report on Form 10-K ("2020 Annual Report"). Principles of Consolidation The accompanying Unaudited Condensed Consolidated Financial Statements include the accounts of Mistras Group, Inc. as well as its wholly-owned subsidiaries, majority-owned subsidiaries and consolidated variable interest entities (VIE). For subsidiaries in which the Company’s ownership interest is less than 100%, the non-controlling interests are reported in stockholders’ equity in the accompanying Condensed Consolidated Balance Sheets. The non-controlling interests in net results, net of tax, is classified separately in the accompanying Unaudited Condensed Consolidated Statements of Loss. All significant intercompany accounts and transactions have been eliminated in consolidation. The results of operations of companies acquired are included from the date of acquisition. Reclassification Certain amounts in prior periods have been reclassified to conform to the current year presentation. Such reclassifications did not have a material effect on the Company's financial condition or results of operations as previously reported Customers For each of the three months ended March 31, 2021 and 2020, no customer represented 10% or more of the Company's revenue. Significant Accounting Policies The Company’s significant accounting policies are disclosed in Note 1– Summary of Significant Accounting Policies and Practices in the 2020 Annual Report. On an ongoing basis, the Company evaluates its estimates and assumptions, including among other things, those related to revenue recognition, long-lived assets, goodwill and acquisitions. Since the date of the 2020 Annual Report, there have been no material changes to the Company's significant accounting policies. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax credit carry-forwards. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is provided if it is more likely than not that some or all of a deferred income tax asset will not be realized. A current tax liability or asset is recognized for the estimated taxes payable or refundable on tax returns for the current and prior years. US GAAP prescribes a minimum recognition threshold a tax position is required to meet before being recognized in the financial statements. US GAAP also provides guidance on de-recognition, measurement, and classification of amounts relating to uncertain tax positions, accounting for and disclosure of interest and penalties, accounting in interim periods and disclosures required. Interest and penalties related to unrecognized tax positions are recognized as incurred within “provision for income taxes” in the consolidated statements of income. The Company continues to evaluate its deferred tax assets each period to determine if a valuation allowance is required based on whether it is more likely than not that some portion of these deferred tax assets will not be realized. As of March 31, 2021 management concluded that it is more likely than not that a substantial portion of the Company's deferred tax assets will be realized. As part of the Company's analysis, it considered both positive and negative factors that impact profitability and whether those factors would lead to a change in the estimate of the Company's deferred tax assets that may be realized in the future. The Company’s effective income tax rate was approximately 32.7% and 13.6% for the three months ended March 31, 2021 and 2020, respectively. The effective income tax rate benefit for the three months ended March 31, 2021 was higher than the statutory rate due to the capitalization of certain non-US intercompany balances which resulted in a deductible foreign exchange loss in the US. The effective income tax rate for the three months ended March 31, 2020 was lower than the statutory rate primarily due to impairments recorded during the interim period for which no income tax benefits will be realized by the Company. However, this unfavorable impact on the Company's effective income tax rate was partially offset by income tax benefits of the CARES Act. In response to the COVID-19 pandemic, the American Rescue Plan Act was signed into law on March 11, 2021. This act, among other things, provides economic relief provisions to individuals and funding to certain businesses and programs. The Company is currently evaluating the impact of this guidance on its consolidated financial position, results of operations, and cash flows, but does not expect it to have a material impact. Recent Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes”. The ASU removes certain exceptions from the guidance in ASC 740 related to intra-period tax allocations, interim calculations and the recognition of deferred tax liabilities for outside basis differences and clarifies and simplifies several other aspects of accounting for income taxes. Different transition methods apply to the various income tax simplifications. The Company adopted ASU 2019-12 effective January 1, 2021. The impact of adopting this standard was not material to the Company’s consolidated financial position, results of operations, and cash flows. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” The amendments provide optional guidance 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 guidance provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another rate that is expected to be discontinued. The amendments in ASU 2020-04 are effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating applicable contracts and the available expedients provided by the new guidance.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The Company derives the majority of its revenue by providing services on a time and material basis, and are short-term in nature. The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers . Performance Obligations The Company provides highly integrated and bundled inspection services to its customers. The majority of the Company's contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and is, therefore, not distinct. For contracts with multiple performance obligations, the Company allocates the contract’s transaction price to each performance obligation using the Company's best estimate of the standalone selling price of each distinct good or service in the contract. The primary method used to estimate standalone selling price is a relative selling price based on price lists. Contract modifications are not routine in the performance of the Company's contracts. Generally, when contracts are modified, the modification is to account for changes in scope to the goods and services that are provided. In most instances, contract modifications are for goods or services that are distinct, and, therefore, are accounted for as a separate contract. The Company's performance obligations are satisfied over time as work progresses or at a point in time. The majority of the Company's revenue is recognized over time as work progresses for the Company's service deliverables, which includes providing testing, inspection and mechanical services to our customers. Revenue is recognized over time based on time and material incurred to date which best portrays the transfer of control to the customer. The Company also utilizes an available practical expedient that provides for revenue to be recognized in an amount that corresponds directly with the value to the customer of the entity’s performance completed to date. Fixed fee arrangements are determined based on expected labor, material, and overhead to be consumed on fulfillment of such services. For these arrangements, revenue is recognized on a cost-to-cost method tracked on an input basis. The majority of our revenue recognized at a point in time is related to product sales when the customer obtains control of the asset, which is generally upon shipment to the customer. Contract costs include labor, material and overhead. The Company expects any significant remaining performance obligations to be satisfied within one year. Contract Estimates The majority of the Company's revenues are short-term in nature. The Company has many master service agreements (MSAs) that specify an overall framework and contract terms when the Company and customers agree upon services or products to be provided. The actual contracting to provide services or furnish products are triggered by a work order, purchase order, or some similar document issued pursuant to a MSA which sets forth the scope of services and/or identifies the products to be provided. From time-to-time, the Company may enter into long-term contracts, which can range from several months to several years. Revenue on certain contracts is recognized as work is performed based on total costs incurred to date in relation to the total estimated costs for the performance of the contract at completion. This includes contract estimates of costs to be incurred for the performance of the contract. Cost estimation is based upon the professional knowledge and experience of the Company's project managers, engineers and financial professionals. Factors that are considered in estimating the work to be completed include the availability of materials, the effect of any delays in the Company's project performance and the recoverability of any claims. Whenever revisions of estimates, contract costs and/or contract values indicate that the contract costs will exceed estimated revenues, thus creating a loss, a provision for the total estimated loss is recorded in that period. Revenue by Category The following series of tables present the disaggregated revenue: Revenue by industry was as follows: Three Months Ended March 31, 2021 Services International Products Corp/Elim Total Oil & Gas $ 84,684 $ 8,008 $ 56 $ — $ 92,748 Aerospace & Defense 11,823 4,317 35 — 16,175 Industrials 8,819 4,849 327 — 13,995 Power generation & Transmission 5,534 1,978 759 — 8,271 Other Process Industries 7,856 2,912 9 — 10,777 Infrastructure, Research & Engineering 3,169 3,756 1,144 — 8,069 Other 2,413 1,828 658 (1,199) 3,700 Total $ 124,298 $ 27,648 $ 2,988 $ (1,199) $ 153,735 Three Months Ended March 31, 2020 Services International Products Corp/Elim Total Oil & Gas $ 83,299 $ 9,104 $ 95 $ — $ 92,498 Aerospace & Defense 14,652 7,415 147 — 22,214 Industrials 12,867 4,919 488 — 18,274 Power generation & Transmission 5,095 1,697 854 — 7,646 Other Process Industries 6,004 2,120 3 — 8,127 Infrastructure, Research & Engineering 4,517 2,461 560 — 7,538 Other 2,439 1,351 665 (1,287) 3,168 Total $ 128,873 $ 29,067 $ 2,812 $ (1,287) $ 159,465 Revenue per key geographic location was as follows: Three Months Ended March 31, 2021 Services International Products Corp/Elim Total United States $ 104,546 $ 208 $ 1,460 $ (391) $ 105,823 Other Americas 18,878 1,177 67 (63) 20,059 Europe 294 25,894 460 (612) 26,036 Asia-Pacific 580 369 1,001 (133) 1,817 Total $ 124,298 $ 27,648 $ 2,988 $ (1,199) $ 153,735 Three Months Ended March 31, 2020 Services International Products Corp/Elim Total United States 109,581 $ 154 $ 1,559 $ (711) $ 110,583 Other Americas 18,735 1,505 278 (153) 20,365 Europe 108 26,235 340 (379) 26,304 Asia-Pacific 449 1,173 635 (44) 2,213 Total $ 128,873 $ 29,067 $ 2,812 $ (1,287) $ 159,465 Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the Consolidated Balance Sheets. Amounts are generally billed as work progresses in accordance with agreed-upon contractual terms, generally at periodic intervals (e.g., weekly, bi-weekly or monthly). Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. However, the Company sometimes receives advances or deposits from its customers before revenue is recognized, resulting in contract liabilities. These assets and liabilities are aggregated on an individual contract basis and reported on the Consolidated Balance Sheets at the end of each reporting period within accounts receivable, net or accrued expenses and other current liabilities. Revenue recognized during the three months ended March 31, 2021 and 2020 that was included in the contract liability balance at the beginning of such year was $1.9 million and $1.6 million, respectively. Changes in the contract asset and liability balances during these periods were not materially impacted by any other factors. The Company applies a practical expedient to expense incremental costs incurred related to obtaining a contract. The Company’s expenses are expected to be amortized over a period less than one year.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation The Company has share-based incentive awards outstanding to its eligible employees and non-employee directors under two equity incentive plans: (i) the 2009 Long-Term Incentive Plan (the "2009 Plan") and (ii) the 2016 Long-Term Incentive Plan (the "2016 Plan"). No further awards may be granted under the 2009 Plan, although one stock option award granted under the 2009 Plan remains outstanding in accordance with its terms. Awards granted under the 2016 Plan may be in the form of stock options, restricted stock units and other forms of share-based incentives, including performance restricted stock units, stock appreciation rights and deferred stock rights. At the annual shareholders meeting on May 19, 2020, the Company’s shareholders approved an amendment to increase the total number of shares that may be issued under the 2016 Plan by 2.0 million, for a total of 3.7 million shares that may be issued under the 2016 Plan. Stock Options For each of the three months ended March 31, 2021 and 2020, the Company did not recognize any share-based compensation expense related to the stock option award, as the one outstanding stock option award was already fully vested. No unrecognized compensation costs remained related to the stock option award as of March 31, 2021. The following table sets forth a summary of the stock option activity, weighted-average exercise prices and options outstanding as of March 31, 2021 and 2020: Three months ended March 31, 2021 2020 Common Stock Options Weighted Average Exercise Price Common Stock Options Weighted Average Exercise Price Outstanding at beginning of period: 5 $ 22.35 5 $ 22.35 Granted — $ — — $ — Exercised — $ — — $ — Expired or forfeited — $ — — $ — Outstanding at end of period: 5 $ 22.35 5 $ 22.35 Restricted Stock Unit Awards For the three months ended March 31, 2021 and March 31, 2020, the Company recognized share-based compensation expense related to restricted stock unit awards of $0.9 million and $1.1 million, respectively. As of March 31, 2021, there was $8.7 million of unrecognized compensation costs, net of estimated forfeitures, related to restricted stock unit awards, which is expected to be recognized over a remaining weighted-average period of 3.0 years. Upon vesting, restricted stock units are generally net share-settled to cover the required withholding tax and the remaining amount is converted into an equivalent number of shares of common stock. A summary of the vesting activity of restricted stock unit awards, with the respective fair value of the awards, is as follows: Three months ended March 31, 2021 2020 Restricted stock awards vested 111 120 Fair value of awards vested $ 1,189 $ 454 A summary of the fully-vested common stock the Company issued to its six non-employee directors, in connection with its non-employee director compensation plan, is as follows: Three months ended March 31, 2021 2020 Awards issued 25 — Grant date fair value of awards issued $ 258 $ — A summary of the Company's outstanding, non-vested restricted share units is as follows: Three months ended March 31, 2021 2020 Units Weighted Units Weighted Outstanding at beginning of period: 1,076 $ 7.41 559 $ 16.92 Granted 519 $ 10.06 — $ — Released (111) $ 15.90 (120) $ 15.87 Forfeited (10) $ 8.69 (3) $ 16.34 Outstanding at end of period: 1,474 $ 7.70 436 $ 17.21 Performance Restricted Stock Units The Company maintains Performance Restricted Stock Units (PRSUs) that have been granted to select executives and senior officers whose ultimate payout is based on the Company’s performance over a one-year period based on specific metrics approved by the Compensation Committee of the Board of Directors of the Company. For 2020, the Compensation Committee approved the following four metrics: 1. Revenue 2. Adjusted EBITDA defined as net income attributable to the Company plus: interest expense, provision for income taxes, depreciation and amortization, share-based compensation expense and certain acquisition related costs (including transaction due diligence costs and adjustments to the fair value of contingent consideration), foreign exchange (gain) loss and, if applicable, certain special items which are noted). 3. Free Cash Flow as a percentage of revenue 4. Return on Average Book Equity defined as net income divided by average book value of shareholders equity. The free cash flow and return on average book equity criteria are relative metrics, the performance of which are based upon how the Company performs relative to a peer group. For 2021, the Compensation Committee made changes to the Company’s equity incentive compensation plan for its executive officers and approved the new target awards for 2021. For 2021, the three metrics are: 1. Free Cash Flow net cash provided by operating activities less purchases of property, plant, equipment and intangible assets and is subject to adjustments approved by the Compensation Committee. 2. Adjusted EBITDA as defined in the 2020 metric section above. 3. Total Shareholder Return (TSR) measures the total return to shareholders of the Company during 2021 versus the total return to the shareholders of a predefined peer group of companies that provide inspection, testing, certification or similar industrial services. The return will be measured by the year over year percent change in share price. The share prices used to calculate the return are the average share price during the 20-trading day period ending on the initial measurement date (the last 20 trading days of 2020), compared to the average share price during the 20-trading day period ending on the final measurement date (the last 20 trading days of 2021). Any cash dividends or distributions paid in 2021 will be added to calculate the return to shareholders during the year. TSR is considered a market condition for which the fair value of PRSUs with this condition is determined using a Monte Carlo valuation model. Key assumptions in the Monte Carlo valuation model included: a. Expected Volatility. Expected volatility of the Company’s common stock at the date of grant was estimated based on a historical average volatility rate for the approximate 1-year performance period. b. Dividend Yield . The dividend yield assumption was based on historical and anticipated dividend payouts (assumed at zero). c. Risk-Free Interest Rate . The risk-free interest rate assumption was based on observed interest rates consistent with the approximate 1-year performance measurement period. PRSUs are equity-classified and compensation costs are initially measured using the fair value of the underlying stock at the date of grant. Compensation costs related to the PRSUs are subsequently adjusted for changes in the expected outcomes of the performance conditions. Compensation cost related to the PRSUs with a market condition is not reversed if the market condition is not achieved, provided the employee requisite service has been rendered. PRSUs generally vest ratably on each of the first four anniversary dates upon completion of the performance period, for a total requisite service period of up to five years and have no dividend rights. A summary of the Company's PRSU activity is as follows: Three months ended March 31, 2021 2020 Units Weighted Units Weighted Outstanding at beginning of period: 333 $ 8.84 260 $ 16.77 Granted 189 $ 12.59 — $ — Performance condition adjustments (125) $ 3.68 1 $ 13.63 Released (22) $ 13.63 (19) $ 19.46 Forfeited — $ — — $ — Outstanding at end of period: 375 $ 12.18 242 $ 15.42 During the three months ended March 31, 2021 and March 31, 2020, the Compensation Committee approved the final calculation of the award metrics for calendar year 2020 and calendar year 2019, respectively. As a result, the calendar year 2020 PRSUs decreased by approximately 125,000 units (related to not achieving the 2020 Return on Average Book Equity metric) and the calendar year 2019 PRSUs increased by approximately 1,000 units. For the three months ended March 31, 2021 and March 31, 2020, the Company recognized aggregate share-based compensation expense related to the awards described above of approximately $0.1 million and $0.3 million, respectively. At March 31, 2021, there was $2.7 million of total unrecognized compensation costs related to approximately 375,000 non-vested PRSUs, which is expected to be recognized over a remaining weighted-average period of 2.7 years.

Earnings (loss) per Share

Earnings (loss) per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings (loss) per Share	Earnings (loss) per Share Basic earnings (loss) per share is computed by dividing net income by the weighted-average number of shares outstanding during the period. Diluted earnings per share is computed by dividing net income by the sum of (1) the weighted-average number of shares of common stock outstanding during the period, and (2) the dilutive effect of assumed conversion of equity awards using the treasury stock method. With respect to the number of weighted-average shares outstanding (denominator), diluted shares reflects: (i) the exercise of options to acquire common stock to the extent that the options’ exercise prices are less than the average market price of common shares during the period and (ii) the pro forma vesting of restricted stock units. The following table sets forth the computations of basic and diluted earnings per share: Three months ended March 31, 2021 2020 Basic loss per share Numerator: Net loss attributable to Mistras Group, Inc. $ (5,362) $ (98,509) Denominator: Weighted average common shares outstanding 29,425 28,963 Basic loss per share $ (0.18) $ (3.40) Diluted loss per share: Numerator: Net loss attributable to Mistras Group, Inc. $ (5,362) $ (98,509) Denominator: Weighted average common shares outstanding 29,425 28,963 Dilutive effect of stock options outstanding — — Dilutive effect of restricted stock units outstanding (1) — — 29,425 28,963 Diluted loss per share $ (0.18) $ (3.40) _______________ (1) For the three months ended March 31, 2021 and 2020, 509,000 and 99,000 shares, respectively, related to restricted stock were excluded from the calculation of diluted EPS due to the net loss for the period.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Acquisitions	Acquisitions Acquisition-Related Expense In the course of its acquisition activities, the Company incurs costs in connection with due diligence, such as professional fees, and other expenses. Additionally, the Company adjusts the fair value of acquisition-related contingent consideration liabilities on a quarterly basis. These amounts are reported as Acquisition-related expense, net on the Unaudited Condensed Consolidated Statements of Loss and were as follows for the three months ended March 31, 2021 and 2020: Three months ended March 31, 2021 2020 Due diligence, professional fees and other transaction costs $ 34 $ — Adjustments to fair value of contingent consideration liabilities 243 (542) Acquisition-related expense, net $ 277 $ (542)

Accounts Receivable, net

Accounts Receivable, net	3 Months Ended
	Mar. 31, 2021
Receivables [Abstract]
Accounts Receivable, net	Accounts Receivable, net Accounts receivable consisted of the following: March 31, 2021 December 31, 2020 Trade accounts receivable $ 120,190 $ 115,841 Allowance for credit losses (8,230) (8,213) Accounts receivable, net $ 111,960 $ 107,628 The Company had $19.8 million and $11.9 million of unbilled revenue accrued as of March 31, 2021 and December 31, 2020, respectively. These amounts are included in the trade accounts receivable balances above. Unbilled revenue is generally billed in the subsequent quarter to their revenue recognition. The Company was contracted to perform inspections of welds on various pipeline projects in Texas for a customer. As of December 31, 2019, approximately $1.4 million of past due receivables were outstanding from this customer. The Company received notice from the customer in December 2019, alleging that the work performed was not in compliance with the contract. The Company recorded a full reserve for this matter during 2019 and the status of this situation has not changed since 2019. See Note 14- Commitments and Contingencies for additional details.

Property, Plant and Equipment,

Property, Plant and Equipment, net	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, net	Property, Plant and Equipment, net Property, plant and equipment consisted of the following: Useful Life (Years) March 31, 2021 December 31, 2020 Land $ 2,779 $ 2,724 Buildings and improvements 30-40 25,282 25,731 Office furniture and equipment 5-8 20,275 19,902 Machinery and equipment 5-7 236,380 234,331 284,716 282,688 Accumulated depreciation and amortization (194,478) (190,007) Property, plant and equipment, net $ 90,238 $ 92,681 Depreciation and amortization expense for each of the three months ended March 31, 2021 and 2020 was approximately $6.1 million and $6.1 million, respectively.

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Changes in the carrying amount of goodwill by segment is shown below: Services International Products and Systems Total Balance at December 31, 2020 $ 190,112 $ 15,896 $ — $ 206,008 Goodwill acquired during the period 362 — — 362 Foreign currency translation 937 (647) — 290 Balance at March 31, 2021 $ 191,411 $ 15,249 $ — $ 206,660 The Company reviews goodwill for impairment on a reporting unit basis on October 1 of each year and whenever events or changes in circumstances indicate the carrying value of goodwill may not be recoverable. During the first quarter of 2020, the Company’s market capitalization declined significantly compared to the fourth quarter of 2019. Over the same period, the equity value of the Company’s peer group, and the overall U.S. stock market also declined significantly amid market volatility. In addition, oil prices had dropped significantly. These declines were driven in large part by the uncertainty surrounding the COVID-19 pandemic and other macroeconomic events such as the geopolitical tensions between OPEC and Russia. Based on these factors, the Company concluded that multiple triggering events occurred and, accordingly, an interim quantitative goodwill impairment test was performed as of the testing date for each reporting unit as of March 31, 2020 (“testing date”). During the first quarter of 2020, the Company also performed an analysis to determine any impairment of long-lived assets (see Note 9- Intangible Assets ) based on the triggering events noted above. In performing the interim quantitative goodwill impairment test and consistent with prior practice, the Company determined the fair value of each of the reporting units using a combination of the income approach and the market approach by assessing each of these valuation methodologies based upon availability and relevance of comparable company data and determining the appropriate weighting. Under the income approach, the fair value for each of the reporting units was determined based on the present value of estimated future cash flows, discounted at an appropriate risk-adjusted rate. The Company used internal forecasts, updated for recent events, to estimate future cash flows with cash flows beyond the specific operating plans estimated using a terminal value calculation, which incorporates historical and forecasted trends, including an estimate of long-term future growth rates, based on the Company’s most recent views of the long-term outlook for each reporting unit. The internal forecasts include assumptions about future market recovery, including the expected demand for the Company’s goods and services. Due to the inherent uncertainties involved in making estimates and assumptions, actual results may differ from those assumed in the forecasts. The Company derived the discount rates using a capital asset pricing model and analyzing published rates for industries relevant to the reporting units to estimate the cost of equity financing. The Company used discount rates that are commensurate with the risks and uncertainties inherent in the respective businesses and in the internally developed forecasts, updated for recent events. The market approach valuations were derived from metrics of publicly traded companies or historically completed transactions of comparable businesses. The selection of comparable businesses was based on the markets in which the reporting units operate considering risk profiles, size, geography, and diversity of products and services. Based upon the results of the interim quantitative goodwill impairment test during the first quarter of 2020, the Company recorded an aggregate impairment charge of $77.1 million, which consisted of $57.2 million in the services reporting unit within the Services segment, and $19.3 million in the European reporting unit and $0.6 million in the Brazilian reporting unit, both within the International segment. The impairment was calculated based on the difference between the estimated fair value and the carrying value of the reporting units and are included in Impairment charges on the Unaudited Condensed Consolidated Statements of Loss for the three months ended March 31, 2020. Subsequent to March 31, 2020 through March 31, 2021, the Company did not identify any changes in circumstances that would indicate the carrying value of goodwill may not be recoverable. Significant adverse changes in future periods could negatively affect the Company's key assumptions and may result in future goodwill impairment charges which could be material.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2021
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	Intangible Assets The gross amount, accumulated amortization and net carrying amount of intangible assets were as follows: March 31, 2021 December 31, 2020 Useful Life Gross Amount Accumulated Amortization Net Carrying Amount Gross Amount Accumulated Amortization Impairment Net Carrying Amount Customer relationships 5-18 $ 112,982 $ (76,526) $ 36,456 $ 116,101 $ (75,649) $ (2,206) $ 38,246 Software/Technology 3-15 51,657 (24,190) 27,467 77,326 (23,519) (25,874) 27,933 Covenants not to compete 2-5 12,636 (12,252) 384 12,833 (12,162) (212) 459 Other 2-12 10,650 (8,734) 1,915 11,120 (8,614) (502) 2,004 Total $ 187,925 $ (121,702) $ 66,222 $ 217,380 $ (119,944) $ (28,794) $ 68,642 Amortization expense for the three months ended March 31, 2021 and 2020 was approximately $2.5 million and $3.4 million, respectively. As described in Note 8- Goodwill , during the first quarter of 2020, there were negative market indicators that were determined to be triggering events indicating a potential impairment of certain long-lived assets within asset groups in the Services, International, and Products and Systems segments, as well as Corporate. The asset groups are groupings of assets and liabilities determined at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Recoverability testing indicated that certain intangible assets and right of use assets (See Note 13- Leases ) were potentially impaired. For asset groups that required an impairment measurement, similar to the valuations performed to determine the goodwill impairment, the Company used income and market approaches to estimate the fair value of the long-lived assets, which requires significant judgment in evaluation of the useful lives of the assets, economic and industry trends, estimated future cash flows, discount rates, and other factors. The result of the analysis was an aggregate impairment charge of $28.8 million, which consisted of $25.9 million to software/technology, $2.2 million to customer relationships, $0.5 million to other intangibles and $0.2 million to covenants not to compete, all of which are in the Services reporting unit within the Services segment and are included in Impairment charges on the Unaudited Condensed Consolidated Statements of Income (Loss) for three months ended March 31, 2020.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: March 31, 2021 December 31, 2020 Accrued salaries, wages and related employee benefits $ 32,674 $ 30,214 Contingent consideration, current portion 563 1,300 Accrued workers’ compensation and health benefits 4,249 3,948 Deferred revenue 8,658 6,538 Pension accrual 2,519 2,519 Right-of-use liability - Operating 10,201 10,348 Other accrued expenses 24,765 23,633 Total $ 83,629 $ 78,500

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: March 31, 2021 December 31, 2020 Senior credit facility $ 125,132 $ 120,312 Senior secured term loan, net of unamortized debt issuance costs of $0.2 million and 0.3 million, respectively 87,891 89,745 Other 9,283 10,159 Total debt 222,306 220,216 Less: Current portion (11,145) (10,678) Long-term debt, net of current portion $ 211,161 $ 209,538 Senior Credit Facility The Company has a credit agreement with its banking group (as amended, the "Credit Agreement") which provides the Company with a revolving line of credit and a $100 million senior secured term loan A facility. Pursuant to the Amendment described below, the revolving line of credit was reduced from $300 million to $175 million. Both the revolving line of credit and the term loan A facility under the Credit Agreement have a maturity date of December 12, 2023. On May 15, 2020, the Company entered into the Third Amendment (the “Amendment”) to the Credit Agreement. The amendment was needed because the Company determined that as a result of the uncertain impact of the COVID-19 pandemic and the significant drop in oil prices, it would not meet the then existing financial covenants in the Credit Agreement for upcoming quarters. Accordingly, the Amendment modified the financial covenants to provide for: i) elimination of the Funded Debt Leverage Ratio (as defined in the Credit Agreement) for the quarters ended June 30 and September 30, 2020 and increased the Funded Debt Leverage ratio to no greater than 5.25 to 1 beginning for the quarter ending December 31, 2020 and decreasing each successive quarter to no greater than 3.50 to 1 for the quarter ended September 30, 2021, and all quarterly periods thereafter; ii) an elimination of the minimum Fixed Charge Coverage Ratio (as defined in the Credit Agreement) for the quarters ended June 30, September 30 and December 31, 2020), a decrease to 1.0 to 1 for the quarter ending March 31, 2021 and returning to 1.25 to 1 for the quarter ending June 30, 2021 and thereafter; iii) the addition of a minimum EBITDA covenant requiring $3.44 million for the three months ending June 30, 2020, $24.25 million for the six months ending September 30, 2020, and $38.55 million for the nine months ending December 31, 2020, with no requirement thereafter; and iv) the addition of a minimum Liquidity (as defined in the Amendment) covenant of not less than $20.0 million at all times through September 30, 2020 and ceasing thereafter. In addition, the Amendment set a LIBOR floor of 1.0% applicable to all LIBOR loans, and increased the LIBOR margin range to 1.50% to 4.15%, in addition to certain other modifications of the Credit Agreement. The Amendment also requires that the Company promptly prepay the outstanding amount under the revolving credit facility in an amount equal to the difference between (a) the aggregate sum of cash and cash equivalents of the Company and its subsidiaries held in the United States minus (b) $10.0 million if, for a period of two (2) consecutive business days, (i) the outstanding amount under the revolving credit facility exceeds $75.0 million and (ii) the sum of such cash and cash equivalents exceeds $10.0 million. The Amendment reduced the Company's total available loan capacity, amongst other things, and as a result, the Company expensed approximately $0.6 million in capitalized debt issuance costs during the second quarter of 2020, which was included in Selling, general and administrative expenses on the Unaudited Condensed Consolidated Statements of Income Loss. The Credit Agreement provides that the Company may not make any acquisitions prior to June 30, 2021, and thereafter only if the Company's Funded Debt Leverage Ratio is less than 2.50 to 1, and after giving effect to such acquisition, its pro forma Funded Debt Leverage Ratio will not be greater than 3.25 to 1. The Company received an amendment from the lenders to complete an immaterial acquisition during three months ended March 31, 2021. The Credit Agreement also limits the Company’s ability to, among other things, create liens, make investments, incur more indebtedness, merge or consolidate, make dispositions of property, pay dividends and make distributions to stockholders or repurchase its stock, enter into a new line of business, enter into transactions with affiliates and enter into burdensome agreements. Under the Credit Agreement, the Company may borrow up to $100 million in non-U.S. Dollar currencies and use up to $20 million of the credit limit for the issuance of letters of credit. As of March 31, 2021, the Company had borrowings of $213.0 million and a total of $4.3 million of letters of credit outstanding under the Credit Agreement. The Company has capitalized costs associated with debt modifications of $1.0 million as of March 31, 2021, which is included in Other Assets on the Condensed Consolidated Balance Sheets. As of March 31, 2021, the Company was in compliance with the terms of the Credit Agreement and will continuously monitor its compliance with the covenants contained in its Credit Agreement. The Company believes that it is probable that the Company will be able to comply with the financial covenants in the Credit Agreement and that sufficient credit remains available under the Credit Agreement to meet the Company's liquidity needs. However, due to the uncertainties being caused by the COVID-19 pandemic, the significant volatility in oil prices, and volatility in the aerospace production, such matters cannot be predicted with certainty. Other debt The Company's other debt includes local bank financing provided at the local subsidiary level used to support working capital requirements and fund capital expenditures. At March 31, 2021, there was an aggregate of approximately $9.3 million outstanding, payable at various times through 2030. Monthly payments range from $1.0 thousand to $18.0 thousand and interest rates range from 0.4% to 3.5%.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company performs fair value measurements in accordance with the guidance provided by ASC 820, Fair Value Measurements and Disclosures. ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. It also establishes a three level hierarchy that prioritizes the inputs used to measure fair value. Financial instruments measured at fair value on a recurring basis The fair value of contingent consideration liabilities was estimated using a discounted cash flow technique with significant inputs that are not observable in the market and thus represents a Level 3 fair value measurement as defined in ASC 820. The significant inputs in the Level 3 measurement not supported by market activity include the probability assessments of expected future cash flows related to the acquisitions, appropriately discounted considering the uncertainties associated with the obligation, and as calculated in accordance with the terms of the applicable acquisition agreements. The following table represents the changes in the fair value of Level 3 contingent consideration: Three months ended March 31, 2021 2020 Beginning balance $ 1,640 $ 3,216 Acquisitions — — Payments (938) (1,303) Accretion of liability — 11 Revaluation 243 (553) Foreign currency translation — (62) Ending balance $ 945 $ 1,309 Financial instruments not measured at fair value on a recurring basis The Company has evaluated current market conditions and borrower credit quality and has determined that the carrying value of its long-term debt approximates fair value. The fair value of the Company’s notes payable and finance lease obligations approximates their carrying amounts based on anticipated interest rates which management believes would currently be available to the Company for similar issuances of debt.

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	Leases The Company’s Condensed Consolidated Balance Sheets include the following related to operating leases: Leases Classification March 31, 2021 December 31, 2020 Assets ROU assets Other Assets $ 44,580 $ 46,728 Liabilities ROU - current Accrued expenses and other current liabilities $ 10,201 $ 10,348 ROU liability - long-term Other long-term liabilities 35,807 37,689 Total ROU liabilities $ 46,008 $ 48,037 Included within the balance of operating leases is a lease for the Company’s headquarters which is with a related party. The ROU liability for this facility was approximately $3.6 million and $3.8 million as of March 31, 2021 and December 31, 2020, respectively. Total rent payments for this facility were approximately $0.5 million and $0.3 million for the three months ended March 31, 2021 and March 31, 2020, respectively. An agreement was reached with the related party to reduce rental payments by 20% and defer payments for 90 days for the lease of the Company’s headquarters, starting in June 2020 through December 2020 as part of COVID-19 related vendor concessions. The total ROU assets attributable to finance leases were approximately $ 15.2 million 15.8 million As described in Note 9- Intangible Assets , the Company performed an analysis to determine whether there was any impairment of long-lived assets, which included the ROU assets, within the Services, International, and Products and Systems operating segments as well as Corporate. The result of the analysis was a $0.2 million impairment of a ROU asset in an asset group within the Services segment which is included in Impairment charges on the Unaudited Condensed Consolidated Statements of Loss for the three months ended March 31, 2020. The components of lease costs were as follows: Three months ended March 31, Classification 2021 2020 Finance lease expense Amortization of ROU assets Depreciation and amortization $ 1,060 $ 1,228 Interest on lease liabilities Interest expense 192 218 Operating lease expense Cost of revenue; Selling, general & administrative expenses 3,302 3,528 Short-term lease expense Cost of revenue; Selling, general & administrative expenses 6 1 Variable lease expense Cost of revenue; Selling, general & administrative expenses 867 349 Total $ 5,427 $ 5,324 Additional information related to leases was as follows: Three months ended March 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities for finance and operating leases Finance - financing cash flows $ 1,069 $ 1,167 Finance - operating cash flows $ 192 $ 217 Operating - operating cash flows $ 3,322 $ 3,291 ROU assets obtained in the exchange for lease liabilities Finance leases $ 643 $ 667 Operating leases $ 1,004 $ 1,625 Weighted-average remaining lease term (in years) Finance leases 5.6 5.9 Operating leases 5.6 6.1 Weighted-average discount rate Finance leases 5.5 % 5.6 % Operating leases 5.7 % 5.8 % Maturities of lease liabilities as of March 31, 2021 were as follows: Finance Operating Remainder of 2021 4,207 $ 9,392 2022 4,214 10,863 2023 3,321 9,233 2024 2,385 7,045 2025 797 5,091 Thereafter 758 12,141 Total 15,682 53,765 Less: Present value discount 1,318 7,757 Lease liability $ 14,364 $ 46,008
Leases	Leases The Company’s Condensed Consolidated Balance Sheets include the following related to operating leases: Leases Classification March 31, 2021 December 31, 2020 Assets ROU assets Other Assets $ 44,580 $ 46,728 Liabilities ROU - current Accrued expenses and other current liabilities $ 10,201 $ 10,348 ROU liability - long-term Other long-term liabilities 35,807 37,689 Total ROU liabilities $ 46,008 $ 48,037 Included within the balance of operating leases is a lease for the Company’s headquarters which is with a related party. The ROU liability for this facility was approximately $3.6 million and $3.8 million as of March 31, 2021 and December 31, 2020, respectively. Total rent payments for this facility were approximately $0.5 million and $0.3 million for the three months ended March 31, 2021 and March 31, 2020, respectively. An agreement was reached with the related party to reduce rental payments by 20% and defer payments for 90 days for the lease of the Company’s headquarters, starting in June 2020 through December 2020 as part of COVID-19 related vendor concessions. The total ROU assets attributable to finance leases were approximately $ 15.2 million 15.8 million As described in Note 9- Intangible Assets , the Company performed an analysis to determine whether there was any impairment of long-lived assets, which included the ROU assets, within the Services, International, and Products and Systems operating segments as well as Corporate. The result of the analysis was a $0.2 million impairment of a ROU asset in an asset group within the Services segment which is included in Impairment charges on the Unaudited Condensed Consolidated Statements of Loss for the three months ended March 31, 2020. The components of lease costs were as follows: Three months ended March 31, Classification 2021 2020 Finance lease expense Amortization of ROU assets Depreciation and amortization $ 1,060 $ 1,228 Interest on lease liabilities Interest expense 192 218 Operating lease expense Cost of revenue; Selling, general & administrative expenses 3,302 3,528 Short-term lease expense Cost of revenue; Selling, general & administrative expenses 6 1 Variable lease expense Cost of revenue; Selling, general & administrative expenses 867 349 Total $ 5,427 $ 5,324 Additional information related to leases was as follows: Three months ended March 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities for finance and operating leases Finance - financing cash flows $ 1,069 $ 1,167 Finance - operating cash flows $ 192 $ 217 Operating - operating cash flows $ 3,322 $ 3,291 ROU assets obtained in the exchange for lease liabilities Finance leases $ 643 $ 667 Operating leases $ 1,004 $ 1,625 Weighted-average remaining lease term (in years) Finance leases 5.6 5.9 Operating leases 5.6 6.1 Weighted-average discount rate Finance leases 5.5 % 5.6 % Operating leases 5.7 % 5.8 % Maturities of lease liabilities as of March 31, 2021 were as follows: Finance Operating Remainder of 2021 4,207 $ 9,392 2022 4,214 10,863 2023 3,321 9,233 2024 2,385 7,045 2025 797 5,091 Thereafter 758 12,141 Total 15,682 53,765 Less: Present value discount 1,318 7,757 Lease liability $ 14,364 $ 46,008

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings and Government Investigations The Company is subject to periodic lawsuits, investigations and claims that arise in the ordinary course of business. The Company cannot predict with certainty the ultimate resolution of lawsuits, investigations and claims asserted against it. Except possibly for certain of the matters described below, the Company does not believe that any currently pending legal proceeding to which the Company is a party will have a material adverse effect on its business, results of operations, cash flows or financial condition. The costs of defense and amounts that may be recovered against the Company may be covered by insurance for certain matters. Litigation and Commercial Claims The Company was contracted to perform inspections of welds on various pipeline projects in Texas for a customer. As of December 31, 2019, approximately $1.4 million of past due receivables were outstanding from this customer. The customer provided the Company with notice in December 2019, alleging that the Company’s inspection of 66 welds (out of approximately 16,000 welds inspected) were not in compliance with the contract, claimed approximately $7.6 million in damages, and requested that the Company pay these damages and any other damages incurred. The Company has filed a lawsuit in the District Court of Bexar County, Texas, 37th Judicial District, in an action captioned Mistras Group, Inc. v. Epic Y-Grade Pipeline LP, to recover the $1.4 million and other amounts due to the Company. The customer filed a counterclaim, alleging breach of contract and seeking recovery of its alleged damages. The Company believes that any successful claim by the customer regarding the Company’s workmanship will be covered by insurance, subject to payment of a deductible. At this time, the Company is unable to determine whether it has any liability in connection with this matter and if so, the amount or range of any such liability, and accordingly, has not established any accruals for this matter. Accordingly, the Company recorded a reserve in the amount of $1.4 million during the twelve months ended December 31, 2019 for these past due receivables. Two proceedings have been filed in California Superior Court for the County of Los Angeles regarding alleged violations of the California Labor Code. Both cases are captioned Justin Price v. Mistras Group, Inc. , one being a purported class action lawsuit on behalf of current and former Mistras employees in California and the other was filed on behalf of the State of California under the California Private Attorney General Act on the basis of the same alleged violations. Both cases are requesting payment of all damages, including unpaid wages, and various fines and penalties available under California law. On May 4, 2021, the Company agreed to a settlement whereby the Company will pay $2.3 million to resolve the allegations in these proceedings and will be responsible for the employer portion of payroll taxes on the amount of the settlement allocated to wages. The settlement is subject to court approval and will cover claims dating back to June 2016 through July 31, 2021. The Company recorded expense of approximately $1.6 million during the three months ended March 31, 2021 related to this settlement, which is in addition to expense of $0.8 million the Company recorded during the three months ended December 31, 2020. Pension Related Contingencies Certain of Company’s subsidiaries had significant reductions in their unionized workers in 2018. The collective bargaining agreements for these employees required contributions for these employees to national multi-employer pension funds. The reduction in employees resulted a subsidiary incurring a complete withdrawal to one of the pension funds under the Employee Retirement Income Security Act of 1974 ("ERISA"), which was fully satisfied in 2019. The Company has determined that the subsidiary is likely to incur partial or complete withdrawal liability to the other pension fund. The balance of the estimated total amount of this potential liability as of March 31, 2021 is approximately $2.5 million, and the charges related to this liability were incurred in 2018 and 2019. Severance and labor disputes During December 2019, the Company executed an agreement to sell the rights of certain customer "staff leasing" contracts related to its German subsidiary for total consideration of approximately $0.1 million, effective January 1, 2020. No other assets or liabilities other than those employee benefits related to employees working on the customer contracts were included in the sale. As of March 31, 2021, the Company has approximately $0.2 million of accrued estimated severance payment obligations, which takes into account the Company's estimate with respect to the employees that have been or will be transitioned to the German subsidiaries' other customers. The $0.2 million of estimated obligations is net of $0.4 million in payments made and $0.9 million in reversals due to employees being transitioned to customer contracts. The Company is entitled to indemnification on certain labor claims from the sellers of a company acquired by its Brazilian subsidiary. The Company and the seller entered into a settlement agreement for $1.0 million, which provides for payment in two installments, the first for approximately 31% of the settlement and the second for the remaining 69%. The first installment in the amount of $0.3 million was paid by the sellers in December 2020 and the Company recognized that amount as a gain in selling, general and administrative expenses in the same period. The remaining payment for $0.6 million was received in the first quarter of 2021 and the Company recognized that amount as a gain in selling, general and administrative expenses in the same period. Acquisition and disposition related contingencies The Company is liable for contingent consideration in connection with certain of its acquisitions. As of March 31, 2021, total potential acquisition-related contingent consideration ranged from zero to approximately $4.3 million and would be payable upon the achievement of specific performance metrics by certain of the acquired companies over the next 1.5 years. During 2018, the Company sold a subsidiary in the Products and Systems segment. As part of the sale, the Company entered into a three-year agreement to purchase products from the buyer, with a cumulative commitment of $2.3 million, of which $1.1 million is remaining as of March 31, 2021. The agreement is based on third-party pricing and the Company's planned purchase requirements over the three-year purchase period to meet the minimum contractual purchases.

Segment Disclosure

Segment Disclosure	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment Disclosure	Segment Disclosure The Company’s three operating segments are: • Services. This segment provides asset protection solutions predominantly in North America, with the largest concentration in the United States, followed by Canada, consisting primarily of NDT, inspection, mechanical and engineering services that are used to evaluate the safety, structural integrity and reliability of critical energy, industrial and public infrastructure and commercial aerospace components. PCMS software and pipeline related software and data analysis solutions are included in this segment. • International. This segment offers services, products and systems similar to those of the other segments to select markets within Europe, the Middle East, Africa, Asia and South America, but not to customers in China and South Korea, which are served by the Products and Systems segment. • Products and Systems. This segment designs, manufactures, sells, installs and services the Company’s asset protection products and systems, including equipment and instrumentation, predominantly in the United States. Costs incurred for general corporate services, including finance, legal, and certain other costs that are provided to the segments are reported within Corporate and eliminations. Sales to the International segment from the Products and Systems segment and subsequent sales by the International segment of the same items are recorded and reflected in the operating performance of both segments. Additionally, engineering charges and royalty fees charged to the Services and International segments by the Products and Systems segment are reflected in the operating performance of each segment. The accounting policies of the reportable segments are the same as those described in Note 1 - Description of Business and Basis of Presentation . Segment income from operations is one of the primary performance measures used by the chief operating decision maker, to assess the performance of each segment and make resource allocation decisions. Certain general and administrative costs such as human resources, information technology and training are allocated to the segments. Segment income from operations excludes interest and other financial charges and income taxes. Corporate and other assets are comprised principally of cash, deposits, property, plant and equipment, domestic deferred taxes, deferred charges and other assets. Corporate loss from operations consists of administrative charges related to corporate personnel and other charges that cannot be readily identified for allocation to a particular segment. Selected consolidated financial information by segment for the periods shown was as follows: (with intercompany transactions eliminated in Corporate and eliminations) Three months ended March 31, 2021 2020 Revenue Services $ 124,298 $ 128,873 International 27,648 29,067 Products and Systems 2,988 2,812 Corporate and eliminations (1,199) (1,287) $ 153,735 $ 159,465 Three months ended March 31, 2021 2020 Gross profit Services $ 31,076 $ 32,237 International 7,625 8,023 Products and Systems 1,281 368 Corporate and eliminations 19 16 $ 40,001 $ 40,644 Income (loss) from operations by operating segment includes intercompany transactions, which are eliminated in Corporate and eliminations. Three months ended March 31, 2021 2020 Income (loss) from operations Services $ 4,548 $ (81,494) International (820) (20,419) Products and Systems (581) (1,680) Corporate and eliminations (7,893) (7,635) $ (4,746) $ (111,228) Three months ended March 31, 2021 2020 Depreciation and amortization Services $ 6,114 $ 7,075 International 2,210 2,140 Products and Systems 228 253 Corporate and eliminations 13 (1) $ 8,565 $ 9,467 March 31, 2021 December 31, 2020 Intangible assets, net Services $ 57,437 $ 58,917 International 7,851 8,664 Products and Systems 931 1,012 Corporate and eliminations 3 49 $ 66,222 $ 68,642 March 31, 2021 December 31, 2020 Total assets Services $ 432,014 $ 427,636 International 122,184 129,228 Products and Systems 11,664 10,996 Corporate and eliminations 18,539 15,453 $ 584,401 $ 583,313 Refer to Note 2 – Revenue , for revenue by geographic area for the three months ended March 31, 2021 and 2020.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events As described in Note 14- Committments and Contingencies , on May 4, 2021, the Company agreed to a settlement of the two California cases, Justin Price v. Mistras Group, Inc.

Description of Business_and B_2

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Unaudited Condensed Consolidated Financial Statements contained in this report have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") and Securities and Exchange Commission guidance allowing for reduced disclosure for interim periods. In the opinion of management, the Unaudited Condensed Consolidated Financial Statements include all adjustments, which are of a normal recurring nature, necessary for a fair presentation of the results for the interim periods of the years ending December 31, 2021 and December 31, 2020. Certain items included in these statements are based on management’s estimates. Actual results may differ from those estimates. The results of operations for any interim period are not necessarily indicative of the results expected for the year. The accompanying Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the notes to the Audited Consolidated Financial Statements contained in the Company's 2020 Annual Report on Form 10-K ("2020 Annual Report").
Principles of Consolidation	Principles of Consolidation The accompanying Unaudited Condensed Consolidated Financial Statements include the accounts of Mistras Group, Inc. as well as its wholly-owned subsidiaries, majority-owned subsidiaries and consolidated variable interest entities (VIE). For subsidiaries in which the Company’s ownership interest is less than 100%, the non-controlling interests are reported in stockholders’ equity in the accompanying Condensed Consolidated Balance Sheets. The non-controlling interests in net results, net of tax, is classified separately in the accompanying Unaudited Condensed Consolidated Statements of Loss. All significant intercompany accounts and transactions have been eliminated in consolidation. The results of operations of companies acquired are included from the date of acquisition.
Reclassification	Reclassification Certain amounts in prior periods have been reclassified to conform to the current year presentation. Such reclassifications did not have a material effect on the Company's financial condition or results of operations as previously reported
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax credit carry-forwards. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is provided if it is more likely than not that some or all of a deferred income tax asset will not be realized. A current tax liability or asset is recognized for the estimated taxes payable or refundable on tax returns for the current and prior years. US GAAP prescribes a minimum recognition threshold a tax position is required to meet before being recognized in the financial statements. US GAAP also provides guidance on de-recognition, measurement, and classification of amounts relating to uncertain tax positions, accounting for and disclosure of interest and penalties, accounting in interim periods and disclosures required. Interest and penalties related to unrecognized tax positions are recognized as incurred within “provision for income taxes” in the consolidated statements of income. The Company continues to evaluate its deferred tax assets each period to determine if a valuation allowance is required based on whether it is more likely than not that some portion of these deferred tax assets will not be realized. As of March 31, 2021 management concluded that it is more likely than not that a substantial portion of the Company's deferred tax assets will be realized. As part of the Company's analysis, it considered both positive and negative factors that impact profitability and whether those factors would lead to a change in the estimate of the Company's deferred tax assets that may be realized in the future. The Company’s effective income tax rate was approximately 32.7% and 13.6% for the three months ended March 31, 2021 and 2020, respectively. The effective income tax rate benefit for the three months ended March 31, 2021 was higher than the statutory rate due to the capitalization of certain non-US intercompany balances which resulted in a deductible foreign exchange loss in the US. The effective income tax rate for the three months ended March 31, 2020 was lower than the statutory rate primarily due to impairments recorded during the interim period for which no income tax benefits will be realized by the Company. However, this unfavorable impact on the Company's effective income tax rate was partially offset by income tax benefits of the CARES Act. In response to the COVID-19 pandemic, the American Rescue Plan Act was signed into law on March 11, 2021. This act, among other things, provides economic relief provisions to individuals and funding to certain businesses and programs. The Company is currently evaluating the impact of this guidance on its consolidated financial position, results of operations, and cash flows, but does not expect it to have a material impact.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes”. The ASU removes certain exceptions from the guidance in ASC 740 related to intra-period tax allocations, interim calculations and the recognition of deferred tax liabilities for outside basis differences and clarifies and simplifies several other aspects of accounting for income taxes. Different transition methods apply to the various income tax simplifications. The Company adopted ASU 2019-12 effective January 1, 2021. The impact of adopting this standard was not material to the Company’s consolidated financial position, results of operations, and cash flows. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” The amendments provide optional guidance 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 guidance provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another rate that is expected to be discontinued. The amendments in ASU 2020-04 are effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating applicable contracts and the available expedients provided by the new guidance.
Revenue	Revenue The Company derives the majority of its revenue by providing services on a time and material basis, and are short-term in nature. The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers . Performance Obligations The Company provides highly integrated and bundled inspection services to its customers. The majority of the Company's contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and is, therefore, not distinct. For contracts with multiple performance obligations, the Company allocates the contract’s transaction price to each performance obligation using the Company's best estimate of the standalone selling price of each distinct good or service in the contract. The primary method used to estimate standalone selling price is a relative selling price based on price lists. Contract modifications are not routine in the performance of the Company's contracts. Generally, when contracts are modified, the modification is to account for changes in scope to the goods and services that are provided. In most instances, contract modifications are for goods or services that are distinct, and, therefore, are accounted for as a separate contract. The Company's performance obligations are satisfied over time as work progresses or at a point in time. The majority of the Company's revenue is recognized over time as work progresses for the Company's service deliverables, which includes providing testing, inspection and mechanical services to our customers. Revenue is recognized over time based on time and material incurred to date which best portrays the transfer of control to the customer. The Company also utilizes an available practical expedient that provides for revenue to be recognized in an amount that corresponds directly with the value to the customer of the entity’s performance completed to date. Fixed fee arrangements are determined based on expected labor, material, and overhead to be consumed on fulfillment of such services. For these arrangements, revenue is recognized on a cost-to-cost method tracked on an input basis. The majority of our revenue recognized at a point in time is related to product sales when the customer obtains control of the asset, which is generally upon shipment to the customer. Contract costs include labor, material and overhead. The Company expects any significant remaining performance obligations to be satisfied within one year. Contract Estimates The majority of the Company's revenues are short-term in nature. The Company has many master service agreements (MSAs) that specify an overall framework and contract terms when the Company and customers agree upon services or products to be provided. The actual contracting to provide services or furnish products are triggered by a work order, purchase order, or some similar document issued pursuant to a MSA which sets forth the scope of services and/or identifies the products to be provided. From time-to-time, the Company may enter into long-term contracts, which can range from several months to several years. Revenue on certain contracts is recognized as work is performed based on total costs incurred to date in relation to the total estimated costs for the performance of the contract at completion. This includes contract estimates of costs to be incurred for the performance of the contract. Cost estimation is based upon the professional knowledge and experience of the Company's project managers, engineers and financial professionals. Factors that are considered in estimating the work to be completed include the availability of materials, the effect of any delays in the Company's project performance and the recoverability of any claims. Whenever revisions of estimates, contract costs and/or contract values indicate that the contract costs will exceed estimated revenues, thus creating a loss, a provision for the total estimated loss is recorded in that period. Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the Consolidated Balance Sheets. Amounts are generally billed as work progresses in accordance with agreed-upon contractual terms, generally at periodic intervals (e.g., weekly, bi-weekly or monthly). Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. However, the Company sometimes receives advances or deposits from its customers before revenue is recognized, resulting in contract liabilities. These assets and liabilities are aggregated on an individual contract basis and reported on the Consolidated Balance Sheets at the end of each reporting period within accounts receivable, net or accrued expenses and other current liabilities.
Fair Value Measurements	Fair Value Measurements The Company performs fair value measurements in accordance with the guidance provided by ASC 820, Fair Value Measurements and Disclosures. ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. It also establishes a three level hierarchy that prioritizes the inputs used to measure fair value. Financial instruments measured at fair value on a recurring basis The fair value of contingent consideration liabilities was estimated using a discounted cash flow technique with significant inputs that are not observable in the market and thus represents a Level 3 fair value measurement as defined in ASC 820. The significant inputs in the Level 3 measurement not supported by market activity include the probability assessments of expected future cash flows related to the acquisitions, appropriately discounted considering the uncertainties associated with the obligation, and as calculated in accordance with the terms of the applicable acquisition agreements. Financial instruments not measured at fair value on a recurring basis The Company has evaluated current market conditions and borrower credit quality and has determined that the carrying value of its long-term debt approximates fair value. The fair value of the Company’s notes payable and finance lease obligations approximates their carrying amounts based on anticipated interest rates which management believes would currently be available to the Company for similar issuances of debt.
Segment Disclosure	Segment Disclosure The Company’s three operating segments are: • Services. This segment provides asset protection solutions predominantly in North America, with the largest concentration in the United States, followed by Canada, consisting primarily of NDT, inspection, mechanical and engineering services that are used to evaluate the safety, structural integrity and reliability of critical energy, industrial and public infrastructure and commercial aerospace components. PCMS software and pipeline related software and data analysis solutions are included in this segment. • International. This segment offers services, products and systems similar to those of the other segments to select markets within Europe, the Middle East, Africa, Asia and South America, but not to customers in China and South Korea, which are served by the Products and Systems segment. • Products and Systems. This segment designs, manufactures, sells, installs and services the Company’s asset protection products and systems, including equipment and instrumentation, predominantly in the United States. Costs incurred for general corporate services, including finance, legal, and certain other costs that are provided to the segments are reported within Corporate and eliminations. Sales to the International segment from the Products and Systems segment and subsequent sales by the International segment of the same items are recorded and reflected in the operating performance of both segments. Additionally, engineering charges and royalty fees charged to the Services and International segments by the Products and Systems segment are reflected in the operating performance of each segment. The accounting policies of the reportable segments are the same as those described in Note 1 - Description of Business and Basis of Presentation . Segment income from operations is one of the primary performance measures used by the chief operating decision maker, to assess the performance of each segment and make resource allocation decisions. Certain general and administrative costs such as human resources, information technology and training are allocated to the segments. Segment income from operations excludes interest and other financial charges and income taxes. Corporate and other assets are comprised principally of cash, deposits, property, plant and equipment, domestic deferred taxes, deferred charges and other assets. Corporate loss from operations consists of administrative charges related to corporate personnel and other charges that cannot be readily identified for allocation to a particular segment.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregated Revenues	The following series of tables present the disaggregated revenue: Revenue by industry was as follows: Three Months Ended March 31, 2021 Services International Products Corp/Elim Total Oil & Gas $ 84,684 $ 8,008 $ 56 $ — $ 92,748 Aerospace & Defense 11,823 4,317 35 — 16,175 Industrials 8,819 4,849 327 — 13,995 Power generation & Transmission 5,534 1,978 759 — 8,271 Other Process Industries 7,856 2,912 9 — 10,777 Infrastructure, Research & Engineering 3,169 3,756 1,144 — 8,069 Other 2,413 1,828 658 (1,199) 3,700 Total $ 124,298 $ 27,648 $ 2,988 $ (1,199) $ 153,735 Three Months Ended March 31, 2020 Services International Products Corp/Elim Total Oil & Gas $ 83,299 $ 9,104 $ 95 $ — $ 92,498 Aerospace & Defense 14,652 7,415 147 — 22,214 Industrials 12,867 4,919 488 — 18,274 Power generation & Transmission 5,095 1,697 854 — 7,646 Other Process Industries 6,004 2,120 3 — 8,127 Infrastructure, Research & Engineering 4,517 2,461 560 — 7,538 Other 2,439 1,351 665 (1,287) 3,168 Total $ 128,873 $ 29,067 $ 2,812 $ (1,287) $ 159,465 Revenue per key geographic location was as follows: Three Months Ended March 31, 2021 Services International Products Corp/Elim Total United States $ 104,546 $ 208 $ 1,460 $ (391) $ 105,823 Other Americas 18,878 1,177 67 (63) 20,059 Europe 294 25,894 460 (612) 26,036 Asia-Pacific 580 369 1,001 (133) 1,817 Total $ 124,298 $ 27,648 $ 2,988 $ (1,199) $ 153,735 Three Months Ended March 31, 2020 Services International Products Corp/Elim Total United States 109,581 $ 154 $ 1,559 $ (711) $ 110,583 Other Americas 18,735 1,505 278 (153) 20,365 Europe 108 26,235 340 (379) 26,304 Asia-Pacific 449 1,173 635 (44) 2,213 Total $ 128,873 $ 29,067 $ 2,812 $ (1,287) $ 159,465

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Stock Option Activity	The following table sets forth a summary of the stock option activity, weighted-average exercise prices and options outstanding as of March 31, 2021 and 2020: Three months ended March 31, 2021 2020 Common Stock Options Weighted Average Exercise Price Common Stock Options Weighted Average Exercise Price Outstanding at beginning of period: 5 $ 22.35 5 $ 22.35 Granted — $ — — $ — Exercised — $ — — $ — Expired or forfeited — $ — — $ — Outstanding at end of period: 5 $ 22.35 5 $ 22.35
Schedule of Vesting Activity of Restricted Stock Unit Awards	A summary of the vesting activity of restricted stock unit awards, with the respective fair value of the awards, is as follows: Three months ended March 31, 2021 2020 Restricted stock awards vested 111 120 Fair value of awards vested $ 1,189 $ 454
Schedule of Fully-vested Common Stock Issued to Non-employee Directors	A summary of the fully-vested common stock the Company issued to its six non-employee directors, in connection with its non-employee director compensation plan, is as follows: Three months ended March 31, 2021 2020 Awards issued 25 — Grant date fair value of awards issued $ 258 $ —
Schedule of Company's Outstanding, Nonvested Restricted Share Units and Performance Restricted Stock Units	A summary of the Company's outstanding, non-vested restricted share units is as follows: Three months ended March 31, 2021 2020 Units Weighted Units Weighted Outstanding at beginning of period: 1,076 $ 7.41 559 $ 16.92 Granted 519 $ 10.06 — $ — Released (111) $ 15.90 (120) $ 15.87 Forfeited (10) $ 8.69 (3) $ 16.34 Outstanding at end of period: 1,474 $ 7.70 436 $ 17.21 A summary of the Company's PRSU activity is as follows: Three months ended March 31, 2021 2020 Units Weighted Units Weighted Outstanding at beginning of period: 333 $ 8.84 260 $ 16.77 Granted 189 $ 12.59 — $ — Performance condition adjustments (125) $ 3.68 1 $ 13.63 Released (22) $ 13.63 (19) $ 19.46 Forfeited — $ — — $ — Outstanding at end of period: 375 $ 12.18 242 $ 15.42

Earnings (loss) per Share (Tabl

Earnings (loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Computations of Basic and Diluted Earnings (Loss) per Share	The following table sets forth the computations of basic and diluted earnings per share: Three months ended March 31, 2021 2020 Basic loss per share Numerator: Net loss attributable to Mistras Group, Inc. $ (5,362) $ (98,509) Denominator: Weighted average common shares outstanding 29,425 28,963 Basic loss per share $ (0.18) $ (3.40) Diluted loss per share: Numerator: Net loss attributable to Mistras Group, Inc. $ (5,362) $ (98,509) Denominator: Weighted average common shares outstanding 29,425 28,963 Dilutive effect of stock options outstanding — — Dilutive effect of restricted stock units outstanding (1) — — 29,425 28,963 Diluted loss per share $ (0.18) $ (3.40) _______________ (1) For the three months ended March 31, 2021 and 2020, 509,000 and 99,000 shares, respectively, related to restricted stock were excluded from the calculation of diluted EPS due to the net loss for the period.

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Schedule of Acquisition-related Expenses	These amounts are reported as Acquisition-related expense, net on the Unaudited Condensed Consolidated Statements of Loss and were as follows for the three months ended March 31, 2021 and 2020: Three months ended March 31, 2021 2020 Due diligence, professional fees and other transaction costs $ 34 $ — Adjustments to fair value of contingent consideration liabilities 243 (542) Acquisition-related expense, net $ 277 $ (542)

Accounts Receivable, net (Table

Accounts Receivable, net (Tables)	3 Months Ended
	Mar. 31, 2021
Receivables [Abstract]
Schedule of Accounts Receivable, Net	Accounts receivable consisted of the following: March 31, 2021 December 31, 2020 Trade accounts receivable $ 120,190 $ 115,841 Allowance for credit losses (8,230) (8,213) Accounts receivable, net $ 111,960 $ 107,628

Property, Plant and Equipment_2

Property, Plant and Equipment, net (Tables)	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment consisted of the following: Useful Life (Years) March 31, 2021 December 31, 2020 Land $ 2,779 $ 2,724 Buildings and improvements 30-40 25,282 25,731 Office furniture and equipment 5-8 20,275 19,902 Machinery and equipment 5-7 236,380 234,331 284,716 282,688 Accumulated depreciation and amortization (194,478) (190,007) Property, plant and equipment, net $ 90,238 $ 92,681

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	Changes in the carrying amount of goodwill by segment is shown below: Services International Products and Systems Total Balance at December 31, 2020 $ 190,112 $ 15,896 $ — $ 206,008 Goodwill acquired during the period 362 — — 362 Foreign currency translation 937 (647) — 290 Balance at March 31, 2021 $ 191,411 $ 15,249 $ — $ 206,660

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2021
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Schedule of Net Carrying Amount of Intangible Assets	The gross amount, accumulated amortization and net carrying amount of intangible assets were as follows: March 31, 2021 December 31, 2020 Useful Life Gross Amount Accumulated Amortization Net Carrying Amount Gross Amount Accumulated Amortization Impairment Net Carrying Amount Customer relationships 5-18 $ 112,982 $ (76,526) $ 36,456 $ 116,101 $ (75,649) $ (2,206) $ 38,246 Software/Technology 3-15 51,657 (24,190) 27,467 77,326 (23,519) (25,874) 27,933 Covenants not to compete 2-5 12,636 (12,252) 384 12,833 (12,162) (212) 459 Other 2-12 10,650 (8,734) 1,915 11,120 (8,614) (502) 2,004 Total $ 187,925 $ (121,702) $ 66,222 $ 217,380 $ (119,944) $ (28,794) $ 68,642

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: March 31, 2021 December 31, 2020 Accrued salaries, wages and related employee benefits $ 32,674 $ 30,214 Contingent consideration, current portion 563 1,300 Accrued workers’ compensation and health benefits 4,249 3,948 Deferred revenue 8,658 6,538 Pension accrual 2,519 2,519 Right-of-use liability - Operating 10,201 10,348 Other accrued expenses 24,765 23,633 Total $ 83,629 $ 78,500

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consisted of the following: March 31, 2021 December 31, 2020 Senior credit facility $ 125,132 $ 120,312 Senior secured term loan, net of unamortized debt issuance costs of $0.2 million and 0.3 million, respectively 87,891 89,745 Other 9,283 10,159 Total debt 222,306 220,216 Less: Current portion (11,145) (10,678) Long-term debt, net of current portion $ 211,161 $ 209,538

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Changes in Fair Value of Level 3 Contingent Consideration	The following table represents the changes in the fair value of Level 3 contingent consideration: Three months ended March 31, 2021 2020 Beginning balance $ 1,640 $ 3,216 Acquisitions — — Payments (938) (1,303) Accretion of liability — 11 Revaluation 243 (553) Foreign currency translation — (62) Ending balance $ 945 $ 1,309

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Schedule of Supplemental Balance Sheet Information	he Company’s Condensed Consolidated Balance Sheets include the following related to operating leases: Leases Classification March 31, 2021 December 31, 2020 Assets ROU assets Other Assets $ 44,580 $ 46,728 Liabilities ROU - current Accrued expenses and other current liabilities $ 10,201 $ 10,348 ROU liability - long-term Other long-term liabilities 35,807 37,689 Total ROU liabilities $ 46,008 $ 48,037
Schedule of Components of Lease Costs and Other Information Related to Leases	The components of lease costs were as follows: Three months ended March 31, Classification 2021 2020 Finance lease expense Amortization of ROU assets Depreciation and amortization $ 1,060 $ 1,228 Interest on lease liabilities Interest expense 192 218 Operating lease expense Cost of revenue; Selling, general & administrative expenses 3,302 3,528 Short-term lease expense Cost of revenue; Selling, general & administrative expenses 6 1 Variable lease expense Cost of revenue; Selling, general & administrative expenses 867 349 Total $ 5,427 $ 5,324 Additional information related to leases was as follows: Three months ended March 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities for finance and operating leases Finance - financing cash flows $ 1,069 $ 1,167 Finance - operating cash flows $ 192 $ 217 Operating - operating cash flows $ 3,322 $ 3,291 ROU assets obtained in the exchange for lease liabilities Finance leases $ 643 $ 667 Operating leases $ 1,004 $ 1,625 Weighted-average remaining lease term (in years) Finance leases 5.6 5.9 Operating leases 5.6 6.1 Weighted-average discount rate Finance leases 5.5 % 5.6 % Operating leases 5.7 % 5.8 %
Schedule of Maturities of Operating Lease Liabilities	Maturities of lease liabilities as of March 31, 2021 were as follows: Finance Operating Remainder of 2021 4,207 $ 9,392 2022 4,214 10,863 2023 3,321 9,233 2024 2,385 7,045 2025 797 5,091 Thereafter 758 12,141 Total 15,682 53,765 Less: Present value discount 1,318 7,757 Lease liability $ 14,364 $ 46,008
Schedule of Maturities of Finance Lease Liabilities	Maturities of lease liabilities as of March 31, 2021 were as follows: Finance Operating Remainder of 2021 4,207 $ 9,392 2022 4,214 10,863 2023 3,321 9,233 2024 2,385 7,045 2025 797 5,091 Thereafter 758 12,141 Total 15,682 53,765 Less: Present value discount 1,318 7,757 Lease liability $ 14,364 $ 46,008

Segment Disclosure (Tables)

Segment Disclosure (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of Selected Consolidated Financial Information by Segment	Selected consolidated financial information by segment for the periods shown was as follows: (with intercompany transactions eliminated in Corporate and eliminations) Three months ended March 31, 2021 2020 Revenue Services $ 124,298 $ 128,873 International 27,648 29,067 Products and Systems 2,988 2,812 Corporate and eliminations (1,199) (1,287) $ 153,735 $ 159,465 Three months ended March 31, 2021 2020 Gross profit Services $ 31,076 $ 32,237 International 7,625 8,023 Products and Systems 1,281 368 Corporate and eliminations 19 16 $ 40,001 $ 40,644 Income (loss) from operations by operating segment includes intercompany transactions, which are eliminated in Corporate and eliminations. Three months ended March 31, 2021 2020 Income (loss) from operations Services $ 4,548 $ (81,494) International (820) (20,419) Products and Systems (581) (1,680) Corporate and eliminations (7,893) (7,635) $ (4,746) $ (111,228) Three months ended March 31, 2021 2020 Depreciation and amortization Services $ 6,114 $ 7,075 International 2,210 2,140 Products and Systems 228 253 Corporate and eliminations 13 (1) $ 8,565 $ 9,467 March 31, 2021 December 31, 2020 Intangible assets, net Services $ 57,437 $ 58,917 International 7,851 8,664 Products and Systems 931 1,012 Corporate and eliminations 3 49 $ 66,222 $ 68,642 March 31, 2021 December 31, 2020 Total assets Services $ 432,014 $ 427,636 International 122,184 129,228 Products and Systems 11,664 10,996 Corporate and eliminations 18,539 15,453 $ 584,401 $ 583,313

Description of Business_and B_3

Description of Business and Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accounting Policies [Abstract]
Cash balance	$ 24,177		$ 25,760
Effective income tax rate	32.70%	13.60%

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized that was included in contract liability balance at the beginning of the year	$ 1.9	$ 1.6
Revenue, practical expedient, incremental cost of obtaining a contract, maximum period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction period	1 year

Revenue - Disaggregated Revenue

Revenue - Disaggregated Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 153,735	$ 159,465
United States
Disaggregation of Revenue [Line Items]
Revenue	105,823	110,583
Other Americas
Disaggregation of Revenue [Line Items]
Revenue	20,059	20,365
Europe
Disaggregation of Revenue [Line Items]
Revenue	26,036	26,304
Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	1,817	2,213
Oil & Gas
Disaggregation of Revenue [Line Items]
Revenue	92,748	92,498
Aerospace & Defense
Disaggregation of Revenue [Line Items]
Revenue	16,175	22,214
Industrials
Disaggregation of Revenue [Line Items]
Revenue	13,995	18,274
Power generation & Transmission
Disaggregation of Revenue [Line Items]
Revenue	8,271	7,646
Other Process Industries
Disaggregation of Revenue [Line Items]
Revenue	10,777	8,127
Infrastructure, Research & Engineering
Disaggregation of Revenue [Line Items]
Revenue	8,069	7,538
Other
Disaggregation of Revenue [Line Items]
Revenue	3,700	3,168
Operating segments | Services
Disaggregation of Revenue [Line Items]
Revenue	124,298	128,873
Operating segments | Services | United States
Disaggregation of Revenue [Line Items]
Revenue	104,546	109,581
Operating segments | Services | Other Americas
Disaggregation of Revenue [Line Items]
Revenue	18,878	18,735
Operating segments | Services | Europe
Disaggregation of Revenue [Line Items]
Revenue	294	108
Operating segments | Services | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	580	449
Operating segments | Services | Oil & Gas
Disaggregation of Revenue [Line Items]
Revenue	84,684	83,299
Operating segments | Services | Aerospace & Defense
Disaggregation of Revenue [Line Items]
Revenue	11,823	14,652
Operating segments | Services | Industrials
Disaggregation of Revenue [Line Items]
Revenue	8,819	12,867
Operating segments | Services | Power generation & Transmission
Disaggregation of Revenue [Line Items]
Revenue	5,534	5,095
Operating segments | Services | Other Process Industries
Disaggregation of Revenue [Line Items]
Revenue	7,856	6,004
Operating segments | Services | Infrastructure, Research & Engineering
Disaggregation of Revenue [Line Items]
Revenue	3,169	4,517
Operating segments | Services | Other
Disaggregation of Revenue [Line Items]
Revenue	2,413	2,439
Operating segments | International
Disaggregation of Revenue [Line Items]
Revenue	27,648	29,067
Operating segments | International | United States
Disaggregation of Revenue [Line Items]
Revenue	208	154
Operating segments | International | Other Americas
Disaggregation of Revenue [Line Items]
Revenue	1,177	1,505
Operating segments | International | Europe
Disaggregation of Revenue [Line Items]
Revenue	25,894	26,235
Operating segments | International | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	369	1,173
Operating segments | International | Oil & Gas
Disaggregation of Revenue [Line Items]
Revenue	8,008	9,104
Operating segments | International | Aerospace & Defense
Disaggregation of Revenue [Line Items]
Revenue	4,317	7,415
Operating segments | International | Industrials
Disaggregation of Revenue [Line Items]
Revenue	4,849	4,919
Operating segments | International | Power generation & Transmission
Disaggregation of Revenue [Line Items]
Revenue	1,978	1,697
Operating segments | International | Other Process Industries
Disaggregation of Revenue [Line Items]
Revenue	2,912	2,120
Operating segments | International | Infrastructure, Research & Engineering
Disaggregation of Revenue [Line Items]
Revenue	3,756	2,461
Operating segments | International | Other
Disaggregation of Revenue [Line Items]
Revenue	1,828	1,351
Operating segments | Products
Disaggregation of Revenue [Line Items]
Revenue	2,988	2,812
Operating segments | Products | United States
Disaggregation of Revenue [Line Items]
Revenue	1,460	1,559
Operating segments | Products | Other Americas
Disaggregation of Revenue [Line Items]
Revenue	67	278
Operating segments | Products | Europe
Disaggregation of Revenue [Line Items]
Revenue	460	340
Operating segments | Products | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	1,001	635
Operating segments | Products | Oil & Gas
Disaggregation of Revenue [Line Items]
Revenue	56	95
Operating segments | Products | Aerospace & Defense
Disaggregation of Revenue [Line Items]
Revenue	35	147
Operating segments | Products | Industrials
Disaggregation of Revenue [Line Items]
Revenue	327	488
Operating segments | Products | Power generation & Transmission
Disaggregation of Revenue [Line Items]
Revenue	759	854
Operating segments | Products | Other Process Industries
Disaggregation of Revenue [Line Items]
Revenue	9	3
Operating segments | Products | Infrastructure, Research & Engineering
Disaggregation of Revenue [Line Items]
Revenue	1,144	560
Operating segments | Products | Other
Disaggregation of Revenue [Line Items]
Revenue	658	665
Corp/Elim
Disaggregation of Revenue [Line Items]
Revenue	(1,199)	(1,287)
Corp/Elim | United States
Disaggregation of Revenue [Line Items]
Revenue	(391)	(711)
Corp/Elim | Other Americas
Disaggregation of Revenue [Line Items]
Revenue	(63)	(153)
Corp/Elim | Europe
Disaggregation of Revenue [Line Items]
Revenue	(612)	(379)
Corp/Elim | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	(133)	(44)
Corp/Elim | Oil & Gas
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Aerospace & Defense
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Industrials
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Power generation & Transmission
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Other Process Industries
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Infrastructure, Research & Engineering
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corp/Elim | Other
Disaggregation of Revenue [Line Items]
Revenue	$ (1,199)	$ (1,287)

Share-Based Compensation - Equi

Share-Based Compensation - Equity Incentive Plans (Details)	May 19, 2020shares	Mar. 31, 2021planshares	Mar. 31, 2020shares	Dec. 31, 2020shares	Dec. 31, 2019shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans | plan		2
Stock option award granted (in shares)		0	0
Stok option award outstanding (in shares)		5,000	5,000	5,000	5,000
2009 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards that may be granted (in shares)		0
Stock option award granted (in shares)		1
Stok option award outstanding (in shares)		1
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in total number of shares authorized for issuance (in shares)	2,000,000
Total number of shares authorized for issuance (in shares)	3,700,000

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Options (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options fully vested (in shares)	1
Unrecognized compensation costs	$ 0
Common Stock Options
Outstanding at beginning of period (in shares)	5,000	5,000
Granted (in shares)	0	0
Exercised (in shares)	0	0
Expired or forfeited (in shares)	0	0
Outstanding at end of period (in shares)	5,000	5,000
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 22.35	$ 22.35
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	0	0
Expired or forfeited (in dollars per share)	0	0
Outstanding at end of period (in dollars per share)	$ 22.35	$ 22,350
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense	$ 0	$ 0

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Stock Unit Awards - Narrative (Details) - Restricted Stock Unit Awards - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense (benefit)	$ 0.9	$ 1.1
Unrecognized compensation cost, net of estimated forfeitures	$ 8.7
Weighted-average period over which unrecognized compensation cost is expected to be recognized (years)	3 years

Share-Based Compensation - Vest

Share-Based Compensation - Vesting Activity of Restricted Stock Unit Awards (Details) - Restricted Stock Unit Awards - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards vested (in shares)	111	120
Fair value of awards vested	$ 1,189	$ 454

Share-Based Compensation - Full

Share-Based Compensation - Fully-vested Common Stock Issued to Non-employee Directors (Details) - Common Stock - Non-employee Directors shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)directorshares	Mar. 31, 2020USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of non-employee directors to whom fully vested common stock is granted | director	6
Awards issued (in shares) | shares	25	0
Grant date fair value of awards issued | $	$ 258	$ 0

Share-Based Compensation - Re_2

Share-Based Compensation - Restricted Stock Units Awards - Activity (Details) - Restricted Stock Unit Awards - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Restricted Stock Units Awards (Units)
Outstanding at beginning of period (in shares)	1,076	559
Granted (in shares)	519	0
Released (in shares)	(111)	(120)
Forfeited (in shares)	(10)	(3)
Outstanding at end of period (in shares)	1,474	436
Weighted Average Grant-Date Fair Value (in dollars per share)
Outstanding at the beginning of period (in dollars per share)	$ 7.41	$ 16.92
Granted (in dollars per share)	10.06	0
Released (in dollars per share)	15.90	15.87
Forfeited (in dollars per share)	8.69	16.34
Outstanding at end of period (in dollars per share)	$ 7.70	$ 17.21

Share-Based Compensation - Perf

Share-Based Compensation - Performance Restricted Stock Units - Narrative (Details) - PRSUs shares in Thousands, $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2019shares	Mar. 31, 2021USD ($)metricshares	Mar. 31, 2020USD ($)shares	Dec. 31, 2020metricshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance award metrics | metric				4
Number of units increased (decreased) during the period (in shares) | shares	1			(125)
Recognized share-based compensation expense (benefit) | $		$ 0.1	$ 0.3
Unrecognized compensation cost | $		$ 2.7
Nonvested shares outstanding (in shares) | shares	260	375	242	333
Weighted-average period over which unrecognized compensation cost is expected to be recognized (years)		2 years 8 months 12 days
Executive and Senior Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (years)		1 year
Requisite service period		5 years
Executive and Senior Officers | Anniversary 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (ratably on each of the first four anniversary date)		25.00%
Executive and Senior Officers | Anniversary 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (ratably on each of the first four anniversary date)		25.00%
Executive and Senior Officers | Anniversary 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (ratably on each of the first four anniversary date)		25.00%
Executive and Senior Officers | Anniversary 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (ratably on each of the first four anniversary date)		25.00%
Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (years)		1 year
Number of performance award metrics | metric		3
Average share price trading period		20 days		20 days
Last days trading period		20 days		20 days
Dividend yield		0.00%

Share-Based Compensation - Pe_2

Share-Based Compensation - Performance Restricted Stock Units - Activity (Details) - PRSUs - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Performance Restricted Stock (Units)
Outstanding at beginning of period (in shares)	333	260
Granted (in shares)	189	0
Performance condition adjustments (in shares)	(125)	1
Released (in shares)	(22)	(19)
Forfeited (in shares)	0	0
Outstanding at end of period (in shares)	375	242
Weighted Average Grant-Date Fair Value (in dollars per share)
Outstanding at the beginning of period (in dollars per share)	$ 8.84	$ 16.77
Granted (in dollars per share)	12.59	0
Performance condition adjustments (in dollars per share)	3.68	13.63
Released (in dollars per share)	13.63	19.46
Forfeited (in dollars per share)	0	0
Outstanding at end of period (in dollars per share)	$ 12.18	$ 15.42

Earnings (loss) per Share (Deta

Earnings (loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic loss per share
Net loss attributable to Mistras Group, Inc.	$ (5,362)	$ (98,509)
Denominator:
Weighted-average common shares outstanding (in shares)	29,425	28,963
Basic loss per share (in dollars per share)	$ (0.18)	$ (3.40)
Denominator:
Weighted-average common shares outstanding (in shares)	29,425	28,963
Dilutive effect of stock options outstanding (in shares)	0	0
Dilutive effect of restricted stock units outstanding (in shares)	0	0
Weighted average common shares outstanding, diluted (in shares)	29,425	28,963
Diluted loss per share (in dollars per share)	$ (0.18)	$ (3.40)
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares excluded from computation of diluted EPS due to net loss for the period (in shares)	509	99

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Business Combinations [Abstract]
Due diligence, professional fees and other transaction costs	$ 34	$ 0
Adjustments to fair value of contingent consideration liabilities	243	(542)
Acquisition-related expense, net	$ 277	$ (542)

Accounts Receivable, net (Detai

Accounts Receivable, net (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Receivables [Abstract]
Trade accounts receivable	$ 120,190	$ 115,841
Allowance for credit losses	(8,230)	(8,213)
Accounts receivable, net	$ 111,960	$ 107,628

Accounts Receivable, net - Narr

Accounts Receivable, net - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled revenues accrued		$ 19,800	$ 11,900
Past due receivables outstanding		$ 111,960	$ 107,628
Texas Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due receivables outstanding	$ 1,400
Texas Customer | Litigation and Commercial Claims
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due receivables outstanding	1,400
Reserve for past due receivables	$ 1,400

Property, Plant and Equipment_3

Property, Plant and Equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Property, Plant and Equipment, net
Property, plant and equipment, gross	$ 284,716		$ 282,688
Accumulated depreciation and amortization	(194,478)		(190,007)
Property, plant and equipment, net	90,238		92,681
Depreciation and amortization expense	6,100	$ 6,100
Land
Property, Plant and Equipment, net
Property, plant and equipment, gross	2,779		2,724
Buildings and improvements
Property, Plant and Equipment, net
Property, plant and equipment, gross	$ 25,282		25,731
Buildings and improvements | Minimum
Property, Plant and Equipment, net
Useful Life (Years)	30 years
Buildings and improvements | Maximum
Property, Plant and Equipment, net
Useful Life (Years)	40 years
Office furniture and equipment
Property, Plant and Equipment, net
Property, plant and equipment, gross	$ 20,275		19,902
Office furniture and equipment | Minimum
Property, Plant and Equipment, net
Useful Life (Years)	5 years
Office furniture and equipment | Maximum
Property, Plant and Equipment, net
Useful Life (Years)	8 years
Machinery and equipment
Property, Plant and Equipment, net
Property, plant and equipment, gross	$ 236,380		$ 234,331
Machinery and equipment | Minimum
Property, Plant and Equipment, net
Useful Life (Years)	5 years
Machinery and equipment | Maximum
Property, Plant and Equipment, net
Useful Life (Years)	7 years

Goodwill - Changes in Carrying

Goodwill - Changes in Carrying Amount of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Goodwill [Roll Forward]
Balance at December 31, 2020	$ 206,008
Goodwill acquired during the period	362
Foreign currency translation	290
Balance at March 31, 2021	206,660
Services
Goodwill [Roll Forward]
Balance at December 31, 2020	190,112
Goodwill acquired during the period	362
Foreign currency translation	937
Balance at March 31, 2021	191,411
International
Goodwill [Roll Forward]
Balance at December 31, 2020	15,896
Goodwill acquired during the period	0
Foreign currency translation	(647)
Balance at March 31, 2021	15,249
Products and Systems
Goodwill [Roll Forward]
Balance at December 31, 2020	0
Goodwill acquired during the period	0
Foreign currency translation	0
Balance at March 31, 2021	$ 0

Goodwill - Narrative (Details)

Goodwill - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Cumulative goodwill impairment		$ 100.2	$ 100.2
COVID-19
Goodwill [Line Items]
Goodwill impairment charge	$ 77.1
Services
Goodwill [Line Items]
Cumulative goodwill impairment		57.2	57.2
Services | COVID-19
Goodwill [Line Items]
Goodwill impairment charge	57.2
International
Goodwill [Line Items]
Cumulative goodwill impairment		29.8	29.8
European Reporting Unit | COVID-19
Goodwill [Line Items]
Goodwill impairment charge	19.3
Brazilian Reporting Unit | COVID-19
Goodwill [Line Items]
Goodwill impairment charge	$ 0.6
Products and Systems
Goodwill [Line Items]
Cumulative goodwill impairment		$ 13.2	$ 13.2

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 187,925	$ 217,380
Accumulated Amortization	(121,702)	(119,944)
Impairment		(28,794)
Net Carrying Amount	66,222	68,642
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	112,982	116,101
Accumulated Amortization	(76,526)	(75,649)
Impairment		(2,206)
Net Carrying Amount	$ 36,456	38,246
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	5 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	18 years
Software/Technology
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 51,657	77,326
Accumulated Amortization	(24,190)	(23,519)
Impairment		(25,874)
Net Carrying Amount	$ 27,467	27,933
Software/Technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	3 years
Software/Technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	15 years
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 12,636	12,833
Accumulated Amortization	(12,252)	(12,162)
Impairment		(212)
Net Carrying Amount	$ 384	459
Covenants not to compete | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	2 years
Covenants not to compete | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	5 years
Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 10,650	11,120
Accumulated Amortization	(8,734)	(8,614)
Impairment		(502)
Net Carrying Amount	$ 1,915	$ 2,004
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	2 years
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	12 years

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangibles	$ 2.5	$ 3.4
COVID-19 | Services
Finite-Lived Intangible Assets [Line Items]
Impairment of intangibles		28.8
Software/Technology | COVID-19 | Services
Finite-Lived Intangible Assets [Line Items]
Impairment of intangibles		25.9
Customer relationships | COVID-19 | Services
Finite-Lived Intangible Assets [Line Items]
Impairment of intangibles		2.2
Other | COVID-19 | Services
Finite-Lived Intangible Assets [Line Items]
Impairment of intangibles		0.5
Covenants not to compete | COVID-19 | Services
Finite-Lived Intangible Assets [Line Items]
Impairment of intangibles		$ 0.2

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued salaries, wages and related employee benefits	$ 32,674	$ 30,214
Contingent consideration, current portion	563	1,300
Accrued workers’ compensation and health benefits	4,249	3,948
Deferred revenue	8,658	6,538
Pension accrual	2,519	2,519
Right-of-use liability - Operating	10,201	10,348
Other accrued expenses	24,765	23,633
Accrued expenses and other current liabilities	$ 83,629	$ 78,500

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total debt	$ 222,306	$ 220,216
Less: Current portion	(11,145)	(10,678)
Long-term debt, net of current portion	211,161	209,538
Senior credit facility
Debt Instrument [Line Items]
Total debt	125,132	120,312
Senior credit facility | Senior Secured Term Loan
Debt Instrument [Line Items]
Unamortized debt issuance costs	200	300
Total debt	87,891	89,745
Other
Debt Instrument [Line Items]
Total debt	$ 9,283	$ 10,159

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details)	May 15, 2020USD ($)d	Mar. 31, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Debt outstanding		$ 222,306,000		$ 220,216,000
Revolving Credit Facility
Debt Instrument [Line Items]
Capitalized debt issuance costs expensed			$ 600,000
Maximum borrowing capacity in non-U.S. Dollar currencies		100,000,000
Maximum amount available for the issuance of letters of credit		20,000,000
Outstanding borrowings		213,000,000
Outstanding letters of credit		4,300,000
Capitalized costs associated with debt modifications		1,000,000
Debt outstanding		125,132,000		120,312,000
Revolving Credit Facility | Senior Secured Term Loan A Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		100,000,000
Debt outstanding		87,891,000		89,745,000
Revolving Credit Facility | Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 300,000,000
Revolving Credit Facility | Credit Agreement | COVID-19
Debt Instrument [Line Items]
Maximum borrowing capacity		175,000,000
Amount deducted from aggregate cash and cash equivalents held by company and it's subsidiaries if prepayment of credit facility is required	$ 10,000,000
Number of consecutive business days | d	2
Maximum amount outstanding under the revolving credit facility if prepayment of facility is required	$ 75,000,000
Cash and cash equivalents if prepayment of facility is required	$ 10,000,000
Revolving Credit Facility | Credit Agreement | COVID-19 | Maximum
Debt Instrument [Line Items]
Funded debt leverage ratio for acquisitions	2.50
Pro forma funded debt leverage ratio	3.25
Revolving Credit Facility | Credit Agreement | COVID-19 | LIBOR
Debt Instrument [Line Items]
Margin percentage	1.00%
Revolving Credit Facility | Credit Agreement | COVID-19 | LIBOR | Minimum
Debt Instrument [Line Items]
Margin percentage	1.50%
Revolving Credit Facility | Credit Agreement | COVID-19 | LIBOR | Maximum
Debt Instrument [Line Items]
Margin percentage	4.15%
Revolving Credit Facility | Credit Agreement | COVID-19 | Quarter ending December 31, 2020 and decreasing each successive quarter
Debt Instrument [Line Items]
Funded debt leverage ratio	5.25
Revolving Credit Facility | Credit Agreement | COVID-19 | Quarter ending September 30, 2021 and all quarterly periods thereafter
Debt Instrument [Line Items]
Funded debt leverage ratio	3.50
Revolving Credit Facility | Credit Agreement | COVID-19 | Quarter ending March 31, 2021
Debt Instrument [Line Items]
Fixed charge coverage ratio	1
Revolving Credit Facility | Credit Agreement | COVID-19 | Quarter ending June 30, 2021
Debt Instrument [Line Items]
Fixed charge coverage ratio	1.25
Revolving Credit Facility | Credit Agreement | COVID-19 | Three months ending June 30, 2020
Debt Instrument [Line Items]
Debt covenant, minimum EBITDA, amount	$ 3,440,000
Revolving Credit Facility | Credit Agreement | COVID-19 | Six months ending September 30, 2020
Debt Instrument [Line Items]
Debt covenant, minimum EBITDA, amount	24,250,000
Revolving Credit Facility | Credit Agreement | COVID-19 | Nine months ending December 31, 2020
Debt Instrument [Line Items]
Debt covenant, minimum EBITDA, amount	38,550,000
Revolving Credit Facility | Credit Agreement | COVID-19 | At all times through September 30, 2021
Debt Instrument [Line Items]
Debt covenant, minimum EBITDA, amount	$ 20,000,000
Other
Debt Instrument [Line Items]
Debt outstanding		9,283,000		$ 10,159,000
Other | Minimum
Debt Instrument [Line Items]
Debt monthly periodic payments		$ 1,000
Interest rate		0.40%
Other | Maximum
Debt Instrument [Line Items]
Debt monthly periodic payments		$ 18,000
Interest rate		3.50%

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Level 3 - Contingent Consideration - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Beginning balance	$ 1,640	$ 3,216
Acquisitions	0	0
Payments	(938)	(1,303)
Accretion of liability	0	11
Revaluation	243	(553)
Foreign currency translation	0	(62)
Ending balance	$ 945	$ 1,309

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets
ROU assets	$ 44,580	$ 46,728
Liabilities
ROU - current	10,201	10,348
ROU liability - long-term	35,807	37,689
Total ROU liabilities	$ 46,008	$ 48,037
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherNoncurrentAssetsMember	us-gaap:OtherNoncurrentAssetsMember
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		7 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
ROU liabilities	$ 46,008		$ 48,037
Total rent payments	3,322	$ 3,291
ROU finance lease assets	$ 15,200		$ 15,800
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, plant and equipment, net		Property, plant and equipment, net
COVID-19 | Services
Lessee, Lease, Description [Line Items]
Impairment of ROU assets		200
Operating Lease Arrangement | Company's Headquarters
Lessee, Lease, Description [Line Items]
ROU liabilities	$ 3,600		$ 3,800
Total rent payments	$ 500	$ 300
Operating Lease Arrangement | Company's Headquarters | COVID-19
Lessee, Lease, Description [Line Items]
Percentage of reduction of rental payments			20.00%
Deferral period of rental payments			90 days

Leases - Components of Lease Co

Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finance lease expense
Amortization of ROU assets	$ 1,060	$ 1,228
Interest on lease liabilities	192	218
Operating lease expense	3,302	3,528
Short-term lease expense	6	1
Variable lease expense	867	349
Total	$ 5,427	$ 5,324

Leases - Additional Information

Leases - Additional Information Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities for finance and operating leases
Finance - financing cash flows	$ 1,069	$ 1,167
Finance - operating cash flows	192	217
Operating - operating cash flows	3,322	3,291
ROU assets obtained in the exchange for lease liabilities
Finance leases	643	667
Operating leases	$ 1,004	$ 1,625
Weighted-average remaining lease term (in years)
Finance leases	5 years 7 months 6 days	5 years 10 months 24 days
Operating leases	5 years 7 months 6 days	6 years 1 month 6 days
Weighted-average discount rate
Finance leases	5.50%	5.60%
Operating leases	5.70%	5.80%

Leases - Maturity of Lease Liab

Leases - Maturity of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Finance
Remainder of 2021	$ 4,207
2022	4,214
2023	3,321
2024	2,385
2025	797
Thereafter	758
Total	15,682
Less: Present value discount	1,318
Lease liability	14,364
Operating
Remainder of 2021	9,392
2022	10,863
2023	9,233
2024	7,045
2025	5,091
Thereafter	12,141
Total	53,765
Less: Present value discount	7,757
Lease liability	$ 46,008	$ 48,037

Commitments and Contingencies (

Commitments and Contingencies (Details)	May 04, 2021USD ($)	Dec. 31, 2020USD ($)installment	Dec. 31, 2019USD ($)weld	Mar. 31, 2021USD ($)claim	Dec. 31, 2020USD ($)installment	Mar. 31, 2020USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2020USD ($)
Litigation
Accounts receivable, net		$ 107,628,000		$ 111,960,000	$ 107,628,000
Contingency charges				1,030,000		$ 0
Pension accrual		2,519,000		$ 2,519,000	2,519,000
Texas Customer
Litigation
Accounts receivable, net			$ 1,400,000
Litigation and Commercial Claims | Various Pipeline Projects for Texas Customer
Litigation
Amount of damages claimed			7,600,000
Litigation and Commercial Claims | Texas Customer
Litigation
Accounts receivable, net			$ 1,400,000
Number or welds not in compliance | weld			66
Number of welds inspected (over) | weld			16,000
Litigation and Commercial Claims | Texas Customer | Various Pipeline Projects for Texas Customer
Litigation
Amount of damages claimed			$ 1,400,000
Class Action
Litigation
Number of proceedings | claim				2
Contingency charges				$ 1,600,000	$ 800,000
Class Action | Subsequent Event
Litigation
Settlement liability	$ 2,300,000
Class Action on Behalf of Employees
Litigation
Number of proceedings | claim				1
Class Action on Behalf of State of California
Litigation
Number of proceedings | claim				1
Pension Related Contingencies
Litigation
Pension accrual				$ 2,500,000
Severance and Labor Disputes | Foreign Subsidiary | Brazil
Litigation
Settlement amount		$ 1,000,000
Number of settlement installments | installment		2			2
Percentage of settlement installments		0.31		0.69	0.31
Gain on settlement		$ 300,000		$ 600,000
Severance and Labor Disputes | Foreign Subsidiary | Right to Customer Contracts | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Germany
Litigation
Contingency charges				200,000
Consideration received on sale of subsidiary								$ 100,000
Payments of severance obligations				400,000
Reversal of severance obligations				900,000
Acquisition and Disposition Related Contingencies
Litigation
Potential acquisition-related contingent consideration, low end of range				0
Potential acquisition-related contingent consideration, high end of range				$ 4,300,000
Contingent consideration payment period based upon achievement of specific performance metrics				1 year 6 months
Acquisition and Disposition Related Contingencies | Foreign Subsidiaries | Products and Systems | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Litigation
Term of agreement to purchase products from the buyer on sale of subsidiary							3 years
Amount of purchased commitment to buy products from the buyer on sale of subsidiary							$ 2,300,000
Remaining balance under purchase commitment agreement				$ 1,100,000

Segment Disclosure (Details)

Segment Disclosure (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)segment	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	3
Financial information by segment
Revenue	$ 153,735	$ 159,465
Gross profit	40,001	40,644
Income (loss) from operations	(4,746)	(111,228)
Depreciation and amortization	8,565	9,467
Intangible assets, net	66,222		$ 68,642
Total assets	584,401		583,313
Operating segments | Services
Financial information by segment
Revenue	124,298	128,873
Gross profit	31,076	32,237
Income (loss) from operations	4,548	(81,494)
Depreciation and amortization	6,114	7,075
Intangible assets, net	57,437		58,917
Total assets	432,014		427,636
Operating segments | International
Financial information by segment
Revenue	27,648	29,067
Gross profit	7,625	8,023
Income (loss) from operations	(820)	(20,419)
Depreciation and amortization	2,210	2,140
Intangible assets, net	7,851		8,664
Total assets	122,184		129,228
Operating segments | Products and Systems
Financial information by segment
Revenue	2,988	2,812
Gross profit	1,281	368
Income (loss) from operations	(581)	(1,680)
Depreciation and amortization	228	253
Intangible assets, net	931		1,012
Total assets	11,664		10,996
Corporate and eliminations
Financial information by segment
Revenue	(1,199)	(1,287)
Gross profit	19	16
Income (loss) from operations	(7,893)	(7,635)
Depreciation and amortization	13	$ (1)
Intangible assets, net	3		49
Total assets	$ 18,539		$ 15,453

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	May 04, 2021USD ($)claim	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Mar. 31, 2020USD ($)
Subsequent Event [Line Items]
Contingency charges		$ 1,030		$ 0
Class Action
Subsequent Event [Line Items]
Contingency charges		$ 1,600	$ 800
Class Action | Subsequent Event
Subsequent Event [Line Items]
Claims settled | claim	2
Settlement liability	$ 2,300