NON-OPERATING REAL PROPERTY (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2013 Item	Dec. 31, 2012
NON-OPERATING REAL PROPERTY
Adjustments to the carrying value of non-operating real properties		$ 0
Number of developments that occurred subsequent to independent appraisals that would indicate that impairment recognition is necessary	0

Represents the number of developments that occurred subsequent to the independent appraisals indicating that impairment recognition is necessary.

No definition available.

Name:	mntg_NumberOfDevelopmentsSubsequentToIndependentAppraisalsIndicatingImpairment
Namespace Prefix:	mntg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration