v3.22.2

CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - USD ($) | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) |  |
Net investment gain (loss), net of tax | $ 159,000 | $ 662,691

X
- Definition The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence. + References No definition available. + Details
Name: | mcvt_GainLossOnEquityInvestments
Namespace Prefix: | mcvt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_StatementOfStockholdersEquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration