Uncompleted Contracts - Gross and Net Amounts of Uncompleted Contracts (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Jun. 30, 2014
Disclosure Customer Contracts Additional Information [Abstract]
Costs incurred and estimated earnings recognized on uncompleted contracts	$ 1,649,633	$ 1,435,242
Billings on uncompleted contracts	1,707,674mtrx_UncompletedContractsBillings	1,470,674mtrx_UncompletedContractsBillings
Total	(58,041)mtrx_UncompletedContractsNet	(35,432)mtrx_UncompletedContractsNet
Shown on balance sheet as:
Costs and estimated earnings in excess of billings on uncompleted contracts	69,573	73,008
Billings on uncompleted contracts in excess of costs and estimated earnings	127,614us-gaap_BillingsInExcessOfCost	108,440us-gaap_BillingsInExcessOfCost
Total	$ (58,041)	$ (35,432)

Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57807-111642

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57795-111642

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c)(3))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 912

-SubTopic 310

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6471842&loc=d3e55302-109406

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c(2), c(3), c(4)

-Article 5

Name:	us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrPrograms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant