Employee Benefit Plans (Details) - USD ($)	12 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Multiemployer Pension Plans
Total contributions made	$ 46,011	$ 54,990	$ 30,369
Contributions to other multiemployer plans	$ 16,054	$ 22,282	11,639
Joint Pension Fund Local Union One Six Four Ibew [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-6031199/001
Pension Protection Act Zone Status	Yellow	Yellow
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 2,635	$ 3,026	2,955
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2017
Boilermaker-Blacksmith National Pension Trust [Member]
Multiemployer Plans [Line Items]
Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date, Description	Described below (1)
Multiemployer Pension Plans
EIN/Pension Plan Number	48-6168020/001
Pension Protection Act Zone Status	Yellow	Yellow
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 7,658	$ 8,330	3,271
Surcharge Imposed	No
Joint Pension Fund Local Union Number One Zero Two [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-1615726/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 3,063	$ 2,395	2,381
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	Jun. 01, 2018
IBEW Local Four Five Six Pension Plan [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-6238995/001
Pension Protection Act Zone Status	Green	Yellow
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 1,168	$ 788	940
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2017
Local 351 IBEW Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-3417366/001
Multiemployer Plans, Certified Zone Status, Description	Described below (2)	Described below (2)
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 5,018	$ 2,608	2,218
Multiemployer Plan, Surcharge	Described below (2)
Expiration Date of Collective-Bargaining Agreement	Sep. 27, 2016
Steamfitters Local Union Number Four Two Zero Pension Plan [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	23-2004424/001
Pension Protection Act Zone Status	Red	Red
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 1,265	$ 937	1,677
Surcharge Imposed	Yes
Expiration Date of Collective-Bargaining Agreement	Apr. 30, 2017
IBEW Local Union Nine Eight Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	23-1990722/001
Pension Protection Act Zone Status	Yellow	Yellow
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 1,653	$ 2,768	1,380
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	Apr. 29, 2017
Indiana Laborers Pension Fund [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	35-6027150/001
Pension Protection Act Zone Status	Yellow	Red
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 2,320	$ 2,519	1,268
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2017
Ironworkers Mid-America Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	36-6488227/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 2,248	$ 2,605	1,156
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2019
Plumbers and Pipefitters Local Union Seven Four Pension Fund [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	51-6015925/001
Pension Protection Act Zone Status	Yellow	Yellow
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 552	$ 4,473	535
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	Jun. 15, 2017
Pipefitters Retirement Fund Local Five Nine Seven [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	62-6105084/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 2,377	$ 2,259	$ 949
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2017

Contributions to other multiemployer plans.

No definition available.

Name:	mtrx_ContributionsToOtherMultiemployerPlans
Namespace Prefix:	mtrx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Multiemployer Plan, Surcharge

+ References

No definition available.

+ Details

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

- Definition

Multiemployer Plans, Certified Zone Status, Description

+ References

No definition available.

+ Details

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

- Definition

Multiemployer plans number.

+ References

No definition available.

+ Details

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

- Definition

Amount of contributions made to multiemployer plans by the 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Indicate the multiemployer plan's certified zone status as currently required by the Pension Protection Act of 2006 or a subsequent amendment thereof. The zone status categories are red (critical status), orange (seriously endangered), yellow (endangered), and green (none of the above). The acceptable values are "red", "orange", "yellow", "green", "other", and "NA". 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

Name:	us-gaap_MultiemployerPlansCertifiedZoneStatus
Namespace Prefix:	us-gaap_
Data Type:	us-types:zoneStatusItemType
Balance Type:	na
Period Type:	duration

- Definition

Expiration date of the collective bargaining arrangement requiring contributions to the multiemployer plan, in CCYY-MM-DD format. 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

Name:	us-gaap_MultiemployerPlansCollectiveBargainingArrangementExpirationDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the significant collective-bargaining arrangements within the range of expiration dates for collective-bargaining arrangements requiring contributions to a multiemployer plan as well as other information to help investors understand the significance of the collective-bargaining agreements and when they expire. 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

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

- Definition

Indicate whether a funding improvement plan or rehabilitation plan has been implemented or is pending for 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. The acceptable values are "no", "pending", "implemented", "other", and "NA".

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (f)(1)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

Name:	us-gaap_MultiemployerPlansFundingImprovementPlanAndRehabilitationPlan
Namespace Prefix:	us-gaap_
Data Type:	us-types:fundingImprovementAndRehabilitationPlanItemType
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

No definition available.

+ Details

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

- Definition

Indicate whether the employer paid a surcharge to the 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. The acceptable values are "no", "yes", and "NA".

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (f)(2)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_LocalThreeFiveOneIbewPensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_IBEWLocalUnionNineEightPensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_IndianaLaborersPensionFundDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_IronworkersMidAmericaPensionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_PlumbersandPipefittersLocalUnionSevenFourPensionFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=mtrx_PipefittersRetirementFundLocalFiveNineSevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: