Loans Held for Investment (“HFI”) and Loans Held for Sale (“HFS”) (Composition of Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans Held for Investment (“HFI”) and Loans Held for Sale (“HFS”)
UPB	$ 68,050	$ 68,050
Cost basis adjustments, net	(751)	(751)
Loans HFI, net	$ 67,299	$ 67,299

Cost basis adjustments to loans receivable, including deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and any other cost basis adjustments.

No definition available.

Name:	mmac_LoansReceivableCostBasisAdjustmentsNet
Namespace Prefix:	mmac_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant