Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Revenue Recognition
Unamortized discounts and loan origination fees	$ 28,812		$ 29,392
Upfront loan origination and closing fees received	1,873	$ 1,031
Investment in LLC equity interest in SLF
Revenue Recognition
Return of capital distributions	$ 14	$ 0

Unamortized amount of discount and loan origination fees on debt investments, as of the balance sheet date.

No definition available.

Name:	mcip_DebtInvestmentsUnamortizedDiscountsAndLoanOriginationFees
Namespace Prefix:	mcip_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from upfront loan origination and closing fees on debt investments.

+ References

No definition available.

+ Details

Name:	mcip_ProceedsFromUpfrontLoanOriginationAndClosingFeesOnDebtInvestments
Namespace Prefix:	mcip_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of distribution received from equity method investee for return of investment, classified as investing activities. Excludes distribution for return on investment, classified as operating activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21D
-URI https://asc.fasb.org/extlink&oid=126954810&loc=SL94080555-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_InvestmentTypeAxis=mcip_InvestmentInEquityOfMrccSeniorLoanFundILlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: