Related Party Transactions, Associated Capital Group (Details) - Associated Capital Group [Member] - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Related Party Transactions [Abstract]
Management fee percentage	20.00%
Management fees		$ 0
Payment made under sublease agreement	$ 26,131	$ 27,113

The amount paid by the organization under sublease agreement.

No definition available.

Name:	mghl_PaymentMadeUnderSubleaseAgreement
Namespace Prefix:	mghl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration