Commitments and Contingencies - Schedule of Future Minimum Rental Payments Required Under Operating Leases in Place (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Sublease Income
Remainder of 2023	$ (204)
2024	(816)
2025	(408)
Total Payments	(1,428)
Operating Leases
Remainder of 2023	5,516
2024	25,248
2025	22,833
2026	21,614
2027	20,631
Thereafter	181,963
Total Payments	277,805
Less: Tenant improvement allowances	(1,346)
Less: Present value adjustment	(59,597)
Operating Lease, Liability	$ 216,862	$ 192,762

Lessee operating lease liability payments due after year four.

No definition available.

Name:	mc_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lessee operating leases liability tenant improvement allowances.

+ References

No definition available.

+ Details

Name:	mc_LesseeOperatingLeasesLiabilityTenantImprovementAllowances
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lessee operating sublease future income.

+ References

No definition available.

+ Details

Name:	mc_LesseeOperatingSubleaseFutureIncome
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lessee operating sublease future income due year two.

+ References

No definition available.

+ Details

Name:	mc_LesseeOperatingSubleaseFutureIncomeDueYearTwo
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lessee operating sublease future income next twelve months.

+ References

No definition available.

+ Details

Name:	mc_LesseeOperatingSubleaseFutureIncomeNextTwelveMonths
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lessee operating sublease future income remainder of fiscal year.

+ References

No definition available.

+ Details

Name:	mc_LesseeOperatingSubleaseFutureIncomeRemainderOfFiscalYear
Namespace Prefix:	mc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Sublease income.

+ References

No definition available.

+ Details

Name:	mc_SubleaseIncomeDueAbstract
Namespace Prefix:	mc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147478964/842-20-50-6

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease having initial or remaining lease term in excess of one year to be paid in remainder of current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147478964/842-20-50-6

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479041/842-20-45-1

+ Details

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