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Interest rate Debt Instrument, Interest Rate, Stated Percentage Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Business Combination and Asset Acquisition [Abstract] Total Mistras Group, Inc. stockholders’ equity Equity, Attributable to Parent Consolidation Items [Axis] Consolidation Items [Axis] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Goodwill impairment charges Goodwill, Impairment Loss Restricted Stock Restricted Stock [Member] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Reporting Unit [Axis] Reporting Unit [Axis] Revenue recognized that was included in contract liability balance at the beginning of the year Contract with Customer, Liability, Revenue Recognized Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Less: net income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest, Excluding Foreign Currency Transaction And Translation Gain (Loss) Net Income (Loss) Attributable to Noncontrolling Interest, Excluding Foreign Currency Transaction And Translation Gain (Loss) Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Subsequent Events [Abstract] Subsequent Events [Abstract] Income (loss) before provision (benefit) for income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Number of proceedings Loss Contingency, New Claims Filed, Number Corp/Elim Corporate and eliminations Corporate And Eliminations [Member] Corporate And Eliminations International International [Member] Represents International, a business segment of the entity. 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Intangible assets, net Net Carrying Amount Intangible Assets, Net (Excluding Goodwill) Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Document Fiscal Period Focus Document Fiscal Period Focus Useful Life (Years) Finite-Lived Intangible Asset, Useful Life Target award percentage Share Based Compensation Arrangement by Share Based Payment Award, Target Percentage Share Based Compensation Arrangement by Share Based Payment Award, Target Percentage Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Title Trading Arrangement, Individual Title Share-based compensation expense Share-Based Payment 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to Non-PEO NEO Compensation Footnote [Text Block] Total liabilities and equity Liabilities and Equity Other assets Other Assets, Noncurrent Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Accounting Policies [Abstract] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Reorganization and other costs Restructuring Costs Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Aerospace & Defense Aerospace and Defense [Member] Aerospace and Defense Arrangement Duration Trading Arrangement Duration Entity Address, City or Town Entity Address, City or Town Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Schedule of Selected Consolidated Financial Information by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Document Transition Report Document Transition Report Award Timing Predetermined Award Timing Predetermined [Flag] Termination Date Trading Arrangement Termination Date Common stock, shares authorized (in shares) Common Stock, Shares Authorized Performance period (years) Share Based Compensation Arrangement by Share Based Payment Award, Award Performance Period Represents the performance period of the entity, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Debt Covenant Period [Domain] Debt Covenant Period [Domain] [Domain] for Debt Covenant Period [Axis] Repayment of revolver Repayments of Lines of Credit Number or welds not in compliance Loss Contingency, Number Of Welds Alleged Not In Compliance Loss Contingency, Number Of Welds Alleged Not In Compliance Fair value measurements Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Adjustments to reconcile net loss to net cash provided by operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Liability Class [Axis] Liability Class [Axis] All Trading Arrangements All Trading Arrangements [Member] Accumulated depreciation and amortization Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization All Adjustments to Compensation All Adjustments to Compensation [Member] Award Timing Disclosures [Line Items] Title of Individual [Domain] Title of Individual [Domain] Compensation Amount Outstanding Recovery Compensation Amount Work in progress and finished goods Inventory, Finished Goods and Work in Process, Net of Reserves Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Fair value of awards vested Grant date fair value of awards issued Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Bad debt provision for troubled customers, net of recoveries Accounts Receivable, Credit Loss Expense (Reversal) Additional paid-in capital Additional Paid in Capital Depreciation Cost, Depreciation Executive Officers Executive Officer [Member] Forfeited (in dollars per share) Forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Subsequent Event Type [Axis] Subsequent Event Type [Axis] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Anniversary 3 Share-Based Payment Arrangement, Tranche Three [Member] Income Taxes Income Tax, Policy [Policy Text Block] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Insider Trading Arrangements [Line Items] Consolidated debt ratio (less than) Debt Instrument, Covenant, Consolidated Debt Leverage Ratio, Lowest Available Margin Applicable Debt Instrument, Covenant, Consolidated Debt Leverage Ratio, Lowest Available Margin Applicable Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Entity Registrant Name Entity Registrant Name North America North America Segment [Member] North America Segment Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Award Timing Method Award Timing Method [Text Block] Adjustment to Compensation, Amount Adjustment to Compensation Amount Anniversary 2 Share-Based Payment Arrangement, Tranche Two [Member] Proceeds from sale of equipment Proceeds from Sale of Property, Plant, and Equipment Adjustments to fair value of contingent consideration liabilities Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Non-controlling interests Equity, Attributable to Noncontrolling Interest Document Period End Date Document Period End Date Proceeds from revolver Proceeds from Lines of Credit Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Adoption Date Trading Arrangement Adoption Date Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Oil & Gas Oil & Gas [Member] Oil & Gas Repayment of long-term debt Repayments of Long-Term Debt Obligations under finance leases, net of current portion Finance Lease, Liability, Noncurrent Entity Central Index Key Entity Central Index Key Schedule of Acquisition-related Expense Schedule of Business Combination Acquisition Related Costs [Table Text Block] Tabular disclosure of acquisition-related costs. Financial information by segment Segment Reporting Information [Line Items] Liabilities: Liabilities, Fair Value Disclosure [Abstract] Recognized share-based compensation expense Recognized share-based compensation expense (benefit) Share-Based Payment Arrangement, Expense Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Gross Amount Finite-Lived Intangible Assets, Gross Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Provision for income taxes Income Tax Expense (Benefit) Income Tax Authority [Domain] Income Tax Authority [Domain] Vesting [Axis] Vesting [Axis] Fair Value Measurements Fair Value Disclosures [Text Block] Average share price trading period Share-based Compensation Arrangement by Share-based Payment Award, Average Share Price Trading Period Share-based Compensation Arrangement by Share-based Payment Award, Average Share Price Trading Period Number of operating segments Number of Operating Segments Name Trading Arrangement, Individual Name Class Action on Behalf of State of California Class Action on Behalf Of State Of California [Member] Class Action on Behalf Of State Of California Capitalized unamortized issuance cost Deferred Debt Issuance Cost, Writeoff Schedule of Disaggregated Revenues Disaggregation of Revenue [Table Text Block] Acquisition-related expense, net Acquisition-related expense, net Acquisition Related Costs and Fair Value Adjustments to Initial Purchase Price Allocation This element represents acquisition-related costs incurred in connection with business combinations which costs have been expensed during the period. This also includes adjustments to the fair value of the initial purchase price allocation for acquisitions including, but not limited to, changes in contingent consideration liabilities and other liabilities, accounts receivable, inventory, fixed assets, other assets, and other acquisition-related intangible assets. Acquisition-related costs also include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. Inventory Inventory Disclosure [Text Block] Petrochemical Petrochemical [Member] Petrochemical Revenue Revenue Revenue from Contract with Customer, Excluding Assessed Tax Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Amendment Flag Amendment Flag Intangible Assets Intangible Assets Disclosure [Text Block] Schedule of Accrued Expenses and Other Current Liabilities Schedule of Accrued Liabilities Deferred Revenue and Contingent Consideration Liabilities Current [Table Text Block] Tabular disclosure of (a) other payables; (b) accrued liabilities; (c) deferred revenue; and (d) the fair value of contingent consideration liabilities, due within one year or within the normal operating cycle if longer. Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Acquisition of business, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Interest, net Interest Paid, Excluding Capitalized Interest, Operating Activities Comprehensive Loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Awards issued (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Amount of acquisition requiring written notice Debt Instrument, Covenant, Threshold Business Acquisition, Minimum Amount Debt Instrument, Covenant, Threshold Business Acquisition, Minimum Amount Credit Facility [Domain] Credit Facility [Domain] Number of days, written notice required prior to an acquisition Debt Instrument, Covenant, Number Of Days Before Business Acquisition, Written Notice Required Debt Instrument, Covenant, Number Of Days Before Business Acquisition, Written Notice Required SOFR margin range Debt Instrument, Basis Spread on Variable Rate Useful Life (Years) Property, Plant and Equipment, Useful Life Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Amount of damages claimed Loss Contingency, Damages Sought, Value Goodwill Goodwill Disclosure [Text Block] Long-term debt, net of current portion Long-Term Debt, Excluding Current Maturities Maximum amount available for the issuance of letters of credit Line of Credit Facility Maximum Borrowing Capacity Available for Issuance of Letters of Credit Represents the maximum amount of borrowing capacity under the revolving credit facility that is available for the issuance of letters of credit. Diluted (in shares) Weighted average common shares outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Schedule of Vesting Activity of Restricted Stock Unit Awards Share-Based Compensation Arrangements by Share-Based Payment Award, Restricted Stock Units, Vested and Expected to Vest [Table Text Block] Intangible Assets, Net (Excluding Goodwill) [Abstract] Intangible Assets, Net (Excluding Goodwill) [Abstract] Increase in total number of shares authorized for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Revenue Revenue from Contract with Customer [Text Block] Purchase of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Company Selected Measure Amount Company Selected Measure Amount Performance condition adjustments (in dollars per share) Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Adjustments In Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Adjustments In Period, Weighted Average Grant Date Fair Value Additional paid-in capital Additional Paid-in Capital [Member] Total assets Total assets Assets Name Awards Close in Time to MNPI Disclosures, Individual Name Litigation Loss Contingencies [Line Items] Cover [Abstract] Subsequent Events Subsequent Events [Text Block] Accounts Receivable, net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Share-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Expensed finance costs Amortization of Debt Issuance Costs United States UNITED STATES Other long-term liabilities Other Liabilities, Noncurrent Accrued salaries, wages and related employee benefits Accrued Salaries Wages and Employee Related Benefits Current Carrying value as of the balance sheet date of the obligations incurred through that date and payable for salaries, wages, and related employee benefit. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle, if longer). Vested (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Non-NEOs Non-NEOs [Member] Segment Disclosure Segment Reporting Disclosure [Text Block] Net change in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Secured Debt Secured Debt [Member] Non-PEO NEO Non-PEO NEO [Member] Equity Component [Domain] Equity Component [Domain] Current portion of finance lease obligations Finance Lease, Liability, Current Adjustment to Compensation: Adjustment to Compensation [Axis] Deferred income taxes Deferred Income Tax Noncash Expense (Benefit) The noncash component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities pertaining to continuing operations. Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Prior Credit Agreement Prior Credit Agreement [Member] Prior Credit Agreement Scenario [Axis] Scenario [Axis] Debt Instrument [Line Items] Debt Instrument [Line Items] Basic (in shares) Weighted average common shares outstanding, basic (in shares) Weighted Average Number of Shares Outstanding, Basic Credit Agreement Credit Agreement [Member] Credit Agreement Entity Current Reporting Status Entity Current Reporting Status Capitalized costs associated with debt modifications Unamortized Debt Issuance Expense Income (loss) from operations Income (loss) from operations Operating Income (Loss) Reclassification Reclassification, Comparability Adjustment [Policy Text Block] Release of claim on receivables Litigation Settlement, Release Of Claim Litigation Settlement, Release Of Claim Last days trading period Share-based Compensation Arrangement by Share-based Payment Award, Last Day Trading Period Share-based Compensation Arrangement by Share-based Payment Award, Last Day Trading Period Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Segments [Axis] Segments [Axis] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Statement Statement [Line Items] Other comprehensive loss: Other Comprehensive Income (Loss), Net of Tax [Abstract] Scenario [Domain] Scenario [Domain] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Outstanding borrowings Long-Term Line of Credit Customer relationships Customer Relationships [Member] Equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Maximum borrowing capacity in non-U.S. Dollar currencies Line Of Credit Facility Maximum Borrowing Capacity In Non-U.S. Currencies Represents the maximum borrowing capacity in non-U.S. dollar currencies under the revolving credit facility. Anniversary 1 Share-Based Payment Arrangement, Tranche One [Member] Noncontrolling Interest Noncontrolling Interest [Member]