Revenue Recognition - Summary of Activity in Contract Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2018	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Contract Liabilities, Beginning balance	$ 9.2	$ 3.9
Contract Liabilities, Revenue recognized that was included in the contract liability at the beginning of the period	(0.3)	(0.8)
Contract Liabilities, Increases due to billings, excluding amounts recognized as revenue during the period		6.1
Contract Liabilities, Net decrease due to billings, excluding amounts recognized as revenue during the period	(2.1)
Contract Liabilities, Ending balance	$ 6.8	$ 9.2

Contract with customer liability increase due to billings excluding amounts recognized as revenue.

No definition available.

Name:	matr_ContractWithCustomerLiabilityIncreaseDueToBillingsExcludingAmountsRecognizedAsRevenue
Namespace Prefix:	matr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contract with customer liability net decrease due to billings excluding amounts recognized as revenue.

+ References

No definition available.

+ Details

Name:	matr_ContractWithCustomerLiabilityNetDecreaseDueToBillingsExcludingAmountsRecognizedAsRevenue
Namespace Prefix:	matr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130531-203044

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130532-203044

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration