v2.4.1.9

BUSINESS INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Business information
Total revenues	$ 99,412us-gaap_InvestmentBankingRevenue	$ 114,517us-gaap_InvestmentBankingRevenue
Total assets	334,934us-gaap_Assets		464,249us-gaap_Assets
Client | Revenue
Business information
Number of clients	1mc_NumberOfClients / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueServicesNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember	1mc_NumberOfClients / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueServicesNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember
United States
Business information
Total revenues	69,431us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = country_US	97,905us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = country_US
Total assets	273,413us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US		378,573us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US
Europe
Business information
Total revenues	25,422us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = us-gaap_EuropeMember	10,549us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = us-gaap_EuropeMember
Total assets	31,622us-gaap_Assets / us-gaap_StatementGeographicalAxis = us-gaap_EuropeMember		52,975us-gaap_Assets / us-gaap_StatementGeographicalAxis = us-gaap_EuropeMember
Rest of world
Business information
Total revenues	4,559us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = mc_RestOfWorldMember	6,063us-gaap_InvestmentBankingRevenue / us-gaap_StatementGeographicalAxis = mc_RestOfWorldMember
Total assets	$ 29,899us-gaap_Assets / us-gaap_StatementGeographicalAxis = mc_RestOfWorldMember		$ 32,701us-gaap_Assets / us-gaap_StatementGeographicalAxis = mc_RestOfWorldMember

X

- Definition

Represents the number of clients.

+ References

No definition available.

+ Details

Name:	mc_NumberOfClients
Namespace Prefix:	mc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

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



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 18

-Article 5

+ Details

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

X

- Definition

Includes (1) underwriting revenue (the spread between the resale price received and the cost of the securities and related expenses) generated through the purchasing, distributing and reselling of new issues of securities (alternatively, could be a secondary offering of a large block of previously issued securities); and (2) fees earned for mergers, acquisitions, divestitures, restructurings, and other types of financial advisory services.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13(b),(d))

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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

X

- Details

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

X

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementGeographicalAxis=mc_RestOfWorldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementGeographicalAxis=us-gaap_EuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: