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Proceeds from issuance of common stock under employee stock purchase plan Proceeds from Stock Plans Expected effective tax rate, year-to-date Expected effective tax rate, year-to-date Expected effective tax rate year-to-date. Income taxes receivable Income Taxes Receivable, Current Gross profit (loss) Gross profit (loss) Gross Profit Revenue from Contract with Customer Revenue from Contract with Customer, Including Assessed Tax Entity Registrant Name Entity Registrant Name Deferred tax remeasurement Deferred tax remeasurement Deferred tax remeasurement due to the enactment of the Tax Cuts and Jobs Act of 2017. The Company's domestic net deferred tax liability balance was remeasured at a lower corporate tax rate, which reduced the net deferred tax liability balance. The downward remeasurement was recorded as a benefit to income tax expense. Translation adjustment Goodwill, Foreign Currency Translation Gain (Loss) Customer Relationships [Member] Customer Relationships [Member] Entity Address, City or Town Entity Address, City or Town Operating lease impairment due to restructuring Operating Lease Impairments Due To Restructuring Operating Lease Impairments Due To Restructuring Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount Total stockholders' equity Balances, beginning Balances, ending Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Intersegment Eliminations [Member] Intersegment Eliminations [Member] Minimum [Member] Minimum [Member] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Common stock, par value Common Stock, Par or Stated Value Per Share Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Amount Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Treasury Stock, Common Treasury Stock, Common [Member] Trading Symbol Trading Symbol Entity File Number Entity File Number Deferred Tax Assets, Foreign Tax Credit Carryforward, After Valuation Allowance Deferred Tax Assets, Foreign Tax Credit Carryforward, After Valuation Allowance Deferred Tax Assets, Foreign Tax Credit Carryforward, After Valuation Allowance Treasury Stock, Common, Shares Treasury Stock, Common, Shares Finite-Lived Intangible Assets, Amortization Expense, Year Four Finite-Lived Intangible Asset, Expected Amortization, Year Four Canada CANADA Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Other income (expense): Other Nonoperating Income (Expense) [Abstract] Restructuring costs incurred mtrx:UnpaidRestructuringCharges Unpaid Restructuring Charges Accrued insurance Accrued Insurance, Current Accounts payable Increase (Decrease) in Accounts Payable Unapproved change orders and claims Construction Contractor, Contract Cost, Subject to Uncertainty, Amount Revenue Revenues Restructuring and Related Cost, Cost Incurred to Date Restructuring and Related Cost, Cost Incurred to Date Income Tax Disclosure Income Tax Disclosure [Text Block] Blended income tax rate Blended income tax rate Blended income tax rate of 28.06% used by the Company for the remainder of Fiscal 2018. The use of this blended rate is stipulated by the Internal Revenue Code in connection with the Tax Cuts and Jobs Act of December 2017, which reduced the federal income tax rate from 35% to 21%. Since the Company has a June 30 fiscal year end, it must use a blend of 21% and 35% for the rest of the current fiscal year. 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Statement [Line Items] Statement [Line Items] CARES Act NOL Carryback Benefit mtrx:MtrxCARESActNOLCarrybackBenefit mtrx:MtrxCARESActNOLCarrybackBenefit Finite-Lived Intangible Assets, Gross Finite-Lived Intangible Assets, Gross Selling, general and administrative expenses Selling, General and Administrative Expense Loss Contingencies [Table] Loss Contingencies [Table] Additional Margin on alternate base rate loans, Minimum Line Of Credit Basis Spread On Alternate Base Rate Minimum Line of credit basis spread on alternate base rate minimum. Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Operating Loss Carryforwards, Limitations on Use Operating Loss Carryforwards, Limitations on Use Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Total Deferred Tax Assets Outstanding in Prior Quarters Total Deferred Tax Assets Generated in the Six Months Ended December 31st, 2021 [Member] Total Deferred Tax Assets Generated in the Six Months Ended December 31st, 2021 Document Transition Report Document Transition Report Local Phone Number Local Phone Number Operating loss Operating Income (Loss) Inventories Increase (Decrease) in Inventories New Accounting Pronouncements, Policy New Accounting Pronouncements, Policy [Policy Text Block] Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Repurchase of common stock for payment of statutory taxes due on equity-based compensation Payments for Repurchase of Other Equity Asset Backed Credit Facility Adjusted Term SOFR Three Month Add On Asset Backed Credit Facility Adjusted Term SOFR Three Month Add On Asset Backed Credit Facility Adjusted Term SOFR Three Month Add On Goodwill Goodwill Net balance at June 30, 2022 Net balance at March 31, 2023 Goodwill Goodwill impairment Goodwill and Intangible Asset Impairment Income Tax Receivable [Domain] Income Tax Receivable [Domain] Income Tax Receivable [Domain] Intangible Assets Including Goodwill Goodwill and Intangible Assets Disclosure [Text Block] Provision (benefit) for federal, state and foreign income taxes Income Tax Expense (Benefit) Geographical [Domain] Geographical [Domain] Deferred Tax Assets, Valuation Allowance Deferred Tax Assets, Valuation Allowance Deferred income taxes Deferred Income Tax Liabilities, Net Goodwill Attributable To Reporting Units At Risk For Impairment Goodwill Attributable To Reporting Units At Risk For Impairment Goodwill Attributable To Reporting Units At Risk For Impairment Income Statement [Abstract] Income Statement [Abstract] Additional Paid-In Capital Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Maximum Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Maximum Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Maximum Transportation equipment Transportation Equipment Gross Transportation Equipment Gross Earnings Per Share, Basic [Abstract] Earnings Per Share, Basic [Abstract] Restricted Cash Restricted Cash, Noncurrent Cost of revenue Cost of Goods and Services Sold Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block] Diluted Diluted weighted average shares (shares) Weighted Average Number of Shares Outstanding, Diluted Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Loss Contingencies [Line Items] Loss Contingencies [Line Items] Line of Credit Facility, Previous Maximum Borrowing Capacity Line of Credit Facility, Previous Maximum Borrowing Capacity Line of Credit Facility, Previous Maximum Borrowing Capacity Common stock—$.01 par value; 60,000,000 shares authorized; 27,888,217 shares issued as of March 31, 2023 and June 30, 2022; 27,037,556 and 26,790,514 shares outstanding as of March 31, 2023 and June 30, 2022, respectively Common Stock, Value, Issued Issuance of deferred shares, shares Deferred Shares Issued Deferred Shares Issued Antidilutive Securities Excluded from the Calculation of Diluted EPS Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Impairment of Intangible Assets, Finite-lived Impairment of Intangible Assets, Finite-Lived Compensating Balance, Amount Compensating Balance, Amount Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning of Period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, End of Period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Foreign currency translation loss (net of tax expense (benefit) of $0 for the three and nine months ended March 31, 2023 and ($16) and $30 for the three and nine months ended March 31, 2022, respectively) Other comprehensive income (loss) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Text Block [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Cumulative impairment loss Goodwill, Impaired, Accumulated Impairment Loss Current liabilities: Liabilities, Current [Abstract] Issuances of common stock Proceeds from Stock Options 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activities Net Cash Provided by (Used in) Investing Activities Finite-Lived Intangible Assets, Remaining Amortization Period Finite-Lived Intangible Assets, Remaining Amortization Period Treasury shares sold to Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Advances under asset-backed credit facility Proceeds from Long-Term Lines of Credit Goodwill, Acquired During Period Goodwill, Acquired During Period Results of Operations Schedule of Segment Reporting Information, by Segment [Table Text Block] Entity Current Reporting Status Entity Current Reporting Status Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Other accrued expenses Other Liabilities, Current Other assets, non-current Other Assets, 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[Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Stock Options [Member] Share-Based Payment Arrangement, Option [Member] Additional Margin On Adjusted Term SOFR Maximum Additional Margin On Adjusted Term SOFR Maximum Additional Margin On Adjusted Term SOFR Maximum Treasury stock, at cost — 850,661 shares as of March 31, 2023, and 1,097,703 shares as of June 30, 2022 Treasury Stock, Value Power Generation Project [Domain] Power Generation Project [Domain] [Domain] for Power Generation Project [Axis] Accounts receivable, allowances Accounts Receivable, Allowance for Credit Loss, Current Fixed-price Contract Fixed-Price Contract [Member] Other Other Nonoperating Income (Expense) Restructuring Costs Restructuring and Related Activities Disclosure [Text Block] Common stock, shares authorized Common Stock, Shares Authorized Tax Credit Carryforward, Valuation Allowance Tax Credit Carryforward, Valuation Allowance Maximum [Member] Maximum [Member] Project [Axis] Power Generation Project [Axis] Power Generation Project [Axis] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Billings on uncompleted contracts in excess of costs and estimated earnings Increase (Decrease) in Contract with Customer, Liability Total current assets Assets, Current Income taxes Income Taxes Paid, Net Deferred income tax Deferred Income Tax Expense Deferred Income Tax Expense Benefit Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability, Revenue Recognized Entity Small Business Entity Small Business Common stock, shares outstanding Shares, Outstanding Net Carrying Amount Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net Prior Year Carryback Income Tax Receivable Prior Year Carryback Income Tax Receivable Prior Year Carryback Income Tax Receivable Asset Backed Credit Facility, Federal Funds Rate Addition Asset Backed Credit Facility, Federal Funds Rate Addition Asset Backed Credit Facility, Federal Funds Rate Addition Increase (Decrease) in Income Taxes Receivable Increase (Decrease) in Income Taxes Receivable Asset Backed Credit Facility Adjusted Term SOFR One Month Add On Asset Backed Credit Facility Adjusted Term SOFR One Month Add On Asset Backed Credit Facility Adjusted Term SOFR One Month Add On Disaggregation of Revenue [Abstract] Disaggregation of Revenue [Abstract] Property, Plant and Equipment Disclosure [Text Block] Property, Plant and Equipment Disclosure [Text Block] Change in net contract balances Change in net contract balances Change in net contract balances from the prior year to the current year. 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Construction Contractor, Receivable, Retainage, after Year One Construction Contractor, Receivable, Retainage, after Year One Issuance of deferred shares Adjustments to Additional Paid in Capital, Other Nonvested Deferred Shares [Member] Nonvested Deferred Shares [Member] Nonvested Deferred Shares [Member] Finite-Lived Intangible Assets, Amortization Expense, Year Two Finite-Lived Intangible Asset, Expected Amortization, Year Two Deferred Tax Liabilities, Net Deferred Tax Liabilities, Net Statement Condensed Consolidated Balance Sheets [Abstract] Statement Condensed Consolidated Balance Sheets [Abstract] Statement Condensed Consolidated Balance Sheets [Abstract] Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Weighted average common shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Contracts Receivable, Claims and Uncertain Amounts Contracts Receivable, Claims and Uncertain Amounts Inventories Inventory, Net Accounts payable Accounts Payable, Current Restructuring costs Restructuring Charges Other assets and liabilities Increase (Decrease) in Other Operating Assets Entity Filer Category Entity Filer Category Issuances of common stock Proceeds from Issuance of Common Stock Basic Weighted average shares outstanding - basic (shares) Weighted Average Number of Shares Outstanding, Basic Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount United States UNITED STATES Commitments and contingencies Commitments and Contingencies Security Exchange Name Security Exchange Name Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Minimum Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Minimum Asset Backed Credit Facility Fixed Charge Coverage Ratio Requirement, Minimum Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Stockholders' equity Stockholders' Equity before Treasury Stock Claim On Power Generation Project [Member] Claim On Power Generation Project [Member] Claim On Power Generation Project [Member] Other Repayments of Other Debt Cover [Abstract] Cover [Abstract] Property, Plant and Equipment, Gross [Abstract] Property, Plant and Equipment, Gross [Abstract] Goodwill impairment Goodwill, Impairment Loss Deferred Tax Assets, Tax Credit Carryforwards, Foreign Deferred Tax Assets, Tax Credit Carryforwards, Foreign Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Prior federal income tax rate Prior federal income tax rate Federal income tax rate prior to the Tax Cuts and Jobs Act. Revenue from Contract with Customer [Text Block] Revenue from Contract with Customer [Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Utility and Power Infrastructure Utility and Power Infrastructure [Member] Utility and Power Infrastructure. Costs and estimated earnings in excess of billings on uncompleted contracts Increase (Decrease) in Contract with Customer, Asset Treasury shares purchased to satisfy tax withholding obligations Other Treasury Share Purchases Other treasury share purchases. Disclosure Customer Contracts Additional Information [Abstract] Disclosure Customer Contracts Additional Information [Abstract] Disclosure - Customer Contracts - Additional Information [Abstract] Goodwill, Written off Related to Sale of Business Unit Goodwill, Written off Related to Sale of Business Unit Total liabilities and stockholders’ equity Liabilities and Equity Accelerated amortization of deferred debt amendment fees Amortization of Debt Issuance Costs Goodwill [Roll Forward] Goodwill [Roll Forward] Repayments of advances under senior secured revolving credit facility Repayments of Long-Term Lines of Credit Restructuring costs by type [Abstract] Restructuring costs by type [Abstract] Restructuring costs by type [Abstract] Dilutive stock options Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Earnings Per Share, Diluted [Abstract] Earnings Per Share, Diluted [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Current Fiscal Year End Date Current Fiscal Year End Date Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Other intangible assets, net of accumulated amortization Total intangible assets, net carrying amount Intangible Assets, Net (Excluding Goodwill) Diluted loss per common share Diluted EPS (US$ per share) Earnings Per Share, Diluted Effective Income Tax Rate Reconciliation, Deduction, Other, Amount Effective Income Tax Rate Reconciliation, Deduction, Other, Amount Gain on sale of property, plant and equipment Gain (Loss) on Disposition of Property Plant Equipment Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Consolidation Items [Axis] Consolidation Items [Axis] Total current liabilities Liabilities, Current Other current assets Other Assets, Current Gross revenues Gross revenues Gross revenues before intersegment eliminations Intellectual Property [Member] Intellectual Property [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Entity Address, Address Line One Entity Address, Address Line One Project Unapproved Change Orders and Claims [Table] Power Generation Project Unapproved Change Orders and Claims [Table] Power Generation Project Unapproved Change Orders and Claims [Table] Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of Intangible Assets, Indefinite-Lived (Excluding Goodwill) Class of Stock [Domain] Class of Stock [Domain] Line of Credit Facility, Remaining Borrowing Capacity Line of Credit Facility, Remaining Borrowing Capacity Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Interest expense Interest Expense Time-and-materials Contract Time-and-Materials Contract [Member] Additional Margin On Adjusted Term SOFR Minimum Additional Margin On Adjusted Term SOFR Minimum Additional Margin On Adjusted Term SOFR Minimum Entity Tax Identification Number Entity Tax Identification Number Restriction of deductibility of certain executive compensation Restriction of deductibility of certain executive compensation Restriction of deductibility of certain executive compensation in excess of $1.0 million. Description of one of the major changes in connection with the Tax Cuts and Jobs Act of December 2017. Alternate Base Rate Margin Alternate Base Rate Margin Alternate Base Rate Margin Revenue from External Customers by Contract Type Disaggregation of Revenue [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Corporate Unallocated Corporate Costs [Member] Unallocated Corporate Costs. Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Costs and estimated earnings in excess of billings on uncompleted contracts Contract with Customer, Asset, after Allowance for Credit Loss, Current Net decrease in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Beginning equity balances, as adjusted Beginning equity balances, as adjusted Beginning equity balances as adjusted for the effects of retrospective impacts of the adoption of a new accounting standard. Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Restructuring and Related Costs [Table Text Block] Restructuring and Related Costs [Table Text Block] Loss on Contracts Loss on Contracts Finite-Lived Intangible Assets, Amortization Expense, Year Five Finite-Lived Intangible Asset, Expected Amortization, Year Five Entity Central Index Key Entity Central Index Key Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Interest income Investment Income, Interest Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Line of Credit Facility, Expiration Date Line of Credit Facility, Expiration Date Other Information Pertaining to Income Taxes Other Information Pertaining to Income Taxes City Area Code City Area Code Assets Assets [Abstract] Construction Contractor, Receivable, Retainage, Year One Construction Contractor, Receivable, Retainage, Year One Expected Remaining Amortization Expense [Abstract] Expected Remaining Amortization Expense [Abstract] Expected Remaining Amortization Expense [Abstract] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Other liabilities Other Liabilities, Noncurrent Investments, Owned, Federal Income Tax Note [Line Items] Investments, Owned, Federal Income Tax Note [Line Items] Other treasury shares purchases, shares Other Treasury Shares Acquired Other treasury shares acquired. Capital expenditures Payments to Acquire Property, Plant, and Equipment Construction equipment Machinery and Equipment, Gross Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Finite-Lived Intangible Assets, Amortization Expense, Next Year Finite-Lived Intangible Asset, Expected Amortization, Year One Computation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Interest Rate at Period End Disclosure Text Block [Abstract]