Summary of Significant Accounting Policies - Revenue Recognition (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2025 USD ($) borrower	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) borrower
Accounting Policies [Abstract]
Return of capital distributions	$ 251	$ 0
Unamortized discounts and loan origination fees	61,844		$ 60,656
Upfront loan origination and closing fees received	$ 13,541	$ 8,894
Number of borrowers with loan or preferred equity securities \| borrower	13		11
Fair value of the company's investments on non-accrual status	$ 45,197		$ 28,676

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

No definition available.

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Period Type:	instant

- Definition

Represents the number of borrowers on with loan or preferred equity securities.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	mcip_
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Balance Type:	debit
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- References

No definition available.

+ Details

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- Definition

This item represents the aggregate fair value of loans held as assets that are in nonaccrual status for which the fair value option has been elected, if the entity's policy is to recognize interest income separately from other changes in fair value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-28

+ Details

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- 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/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 21D
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-21D

+ Details

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