Description of Business & Basis of Presentation (Details)	3 Months Ended
Feb. 28, 2014 item
Principles of Consolidation
Difference of period between the consolidation of International segment subsidiaries	1 month
Number of months less than the actual number of months from the acquisition date for which results of international segment subsidiaries are included in consolidation	1

Represents the number of months less than the actual period from the acquisition date for which results of the International segment subsidiaries are included in the consolidation.

No definition available.

Name:	mg_NumberOfMonthsLessThanActualPeriodFromAcquisitionForWhichResultsOfInternationalSegmentSubsidiariesAreIncludedInConsolidation
Namespace Prefix:	mg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration