Related Party Transactions, Transactions with Associated Capital Group (Details) - Associated Capital Group [Member] - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related Party Transactions [Abstract]
Management fee percentage	20.00%		20.00%
Management fees	$ 0	$ 0	$ 0	$ 0
Expenses incurred under sublease agreement	$ 4,988	$ 26,211	$ 57,231	$ 79,535

The amount of expenses incurred by the organization under sublease agreement.

No definition available.

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