Employee Benefit Plans (Details) - USD ($)	12 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Multiemployer Plans [Line Items]
Contributions to other multiemployer plans	$ 3,969,000	$ 3,110,000	$ 3,449,000
Total contributions made	$ 23,556,000	$ 16,818,000	15,369,000
Boilermaker-Blacksmith National Pension Trust [Member]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	48-6168020/001
Multiemployer Plans, Underfunded Status, Description	Red	Yellow
FIP/RP Status Pending or Implemented	Implemented
Multiemployer Plan, Employer Contribution, Cost	$ 5,284,000	$ 5,208,000	4,003,000
Surcharge Imposed	Yes
National Electrical Benefit Fund, Local 488 and 126 [Member]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	53-0181657/001
Multiemployer Plans, Underfunded Status, Description	Described below (1)	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 3,437,000	$ 2,973,000	1,865,000
Surcharge Imposed	No
Joint Pension Fund Local Union One Six Four Ibew [Domain]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	22-6031199/001
Multiemployer Plans, Underfunded Status, Description	Green	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 1,724,000	$ 1,514,000	1,958,000
Surcharge Imposed	No
Joint Pension Fund Local Union Number 102 IBEW [Member] [Domain]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	22-1615726/001
Multiemployer Plans, Underfunded Status, Description	Green	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 1,143,000	$ 906,000	1,341,000
Surcharge Imposed	No
IBEW Local 456 Pension Plan [Member] [Domain]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	22-6238995/001
Multiemployer Plans, Underfunded Status, Description	Green	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 1,180,000	$ 734,000	595,000
Surcharge Imposed	No
Local 351 IBEW Pension Plan [Member]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	22-3417366/001
Multiemployer Plans, Underfunded Status, Description	Described below (1)	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 1,033,000	$ 395,000	479,000
Surcharge Imposed	No
Steamfitters Local Union Number 420 Pension Plan [Member] [Domain]
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	23-2004424/001
Multiemployer Plans, Underfunded Status, Description	Red	Yellow
FIP/RP Status Pending or Implemented	Implemented
Multiemployer Plan, Employer Contribution, Cost	$ 656,000	$ 498,000	442,000
Surcharge Imposed	Yes
IBEW Local 654 Pension Plan
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	23-6538183/001
Multiemployer Plans, Underfunded Status, Description	Green	Green
FIP/RP Status Pending or Implemented	NA
Multiemployer Plan, Employer Contribution, Cost	$ 1,242,000	$ 857,000	818,000
Surcharge Imposed	No
Pipefitters Local Four Six Zero Pension Plan
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	51-6108443/001
Multiemployer Plans, Underfunded Status, Description	Described below (1)	Green
FIP/RP Status Pending or Implemented		NA
Multiemployer Plan, Employer Contribution, Cost	$ 2,479,000	$ 111,000	0
Surcharge Imposed	No
Pipefitters Local 342 Pension Plan
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	94-3190386/001
Multiemployer Plans, Underfunded Status, Description	Green	Green
FIP/RP Status Pending or Implemented		NA
Multiemployer Plan, Employer Contribution, Cost	$ 498,000	$ 345,000	101,000
Surcharge Imposed	No
IBEW Local 98 Pension Plan
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	23-6583334/001
Multiemployer Plans, Underfunded Status, Description	Yellow	Red
FIP/RP Status Pending or Implemented		Implemented
Multiemployer Plan, Employer Contribution, Cost	$ 484,000	$ 143,000	318,000
Surcharge Imposed	No
Laborers Local 220 Pension Plan
Multiemployer Plans [Line Items]
EIN/Pension Plan Number	43-6159056/001
Multiemployer Plans, Underfunded Status, Description	Described below (1)	Green
FIP/RP Status Pending or Implemented		NA
Multiemployer Plan, Employer Contribution, Cost	$ 427,000	$ 24,000	$ 0
Surcharge Imposed	No

Multiemployer plans number.

No definition available.

Name:	mtrx_MultiemployerPlansNumber
Namespace Prefix:	mtrx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cost for employer contribution to multiemployer plan. Multiemployer plan includes, but is not limited to, pension plan determined to be individually significant and insignificant and other postretirement benefit plan.

+ References

+ Details

Name:	us-gaap_MultiemployerPlanEmployerContributionCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for employer contribution to multiemployer pension plan determined to be individually insignificant.

+ References

+ Details

Name:	us-gaap_MultiemployerPlanPensionInsignificantEmployerContributionCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for employer contribution to multiemployer pension plan determined to be individually significant.

+ References

+ Details

Name:	us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Indicates whether funding improvement plan or rehabilitation plan was implemented or pending for multiemployer pension plan, determined to be individually significant. Acceptable values are "No", "Pending", "Implemented", "Other", and "NA".

+ References

+ Details

Name:	us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList
Namespace Prefix:	us-gaap_
Data Type:	us-types:fundingImprovementAndRehabilitationPlanItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates whether employer paid surcharge to multiemployer pension plan determined to be individually significant. Acceptable values are "No", "Yes" and "NA".

+ References

+ Details

Name:	us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList
Namespace Prefix:	us-gaap_
Data Type:	us-types:surchargeItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480547/715-80-55-8

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-6

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-6

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-11

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-11

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 35
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480606/715-80-35-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-11

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-9

Reference 19: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-6

+ Details

Name:	us-gaap_MultiemployerPlansLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the extent to which the employer could be responsible for obligations of the multiemployer plan, including benefits earned by employees during employment with another employer. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (b)
-SubTopic 80
-Topic 715
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-7

+ Details

Name:	us-gaap_MultiemployerPlansUnderfundedStatusDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_BoilermakerBlacksmithNationalPensionTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_NationalElectricalBenefitFundLocal488And126Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_JointPensionFundLocalUnionOneSixFourIbewMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_JointPensionFundLocalUnionNumberOneZeroTwoMemberDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_IBEWLocalFourFiveSixPensionPlanMemberDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_LocalThreeFiveOneIbewPensionPlanDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_SteamfittersLocalUnionNumberFourTwoZeroPensionPlanMemberDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_IBEWLocal654PensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_PipefittersLocal460PensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_PipefittersLocal342PensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_IBEWLocal98PensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mtrx_LaborersLocal220PensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: