Name:	mrc_DebtGuarantyAbstract
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The percentage of holdback considered as contingent liability.

No definition available.

Name:	mrc_PercentageOfHoldbackConsideredAsContingentLiability
Namespace Prefix:	mrc_
Data Type:	dtr-types:percentItemType
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Period Type:	instant

The percentage of holdback reduced by stabilization costs.

No definition available.

Name:	mrc_PercentageOfHoldbackReducedByStabilizationCosts
Namespace Prefix:	mrc_
Data Type:	dtr-types:percentItemType
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The percentage of reduced purchase price paid at closing for the general partnership interest.

No definition available.

Name:	mrc_PercentageOfReducedPurchasePriceForGeneralPartnershipInterest
Namespace Prefix:	mrc_
Data Type:	dtr-types:percentItemType
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Period Type:	instant

Amount of written off contingent consideration in noncash financing activities.

No definition available.

Name:	mrc_WrittenOffContingentConsideration
Namespace Prefix:	mrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Amount of liability recognized arising from contingent consideration in a business combination.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126966325&loc=d3e6819-128478

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

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

Amount of cash outflow, made soon after acquisition date of business combination, to settle contingent consideration liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585