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MARKETABLE SECURITIES (Detail Textuals) | 6 Months Ended
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Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items] |
Period of current marketable securities | less than 12 months
Period of non-current marketable securities | greater than 12 months
Maturity term of non-current marketable securities | 2015 and 2041
Municipal Obligations | A3 or higher |
Schedule of Available-for-sale Securities [Line Items] |
Period of maturity of debt obligations | less than one year to over 10 years
Corporate Obligations | A3 or higher |
Schedule of Available-for-sale Securities [Line Items] |
Period of maturity of debt obligations | one to four years

X
- Definition Describe the approximate maturity term of non-current marketable securities. + References No definition available. + Details
Name: | mpx_MaturityPeriodOfNonCurrentMarketableSecurities
Namespace Prefix: | mpx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition This element represents period of current marketable securities. + References No definition available. + Details
Name: | mpx_PeriodOfCurrentMarketableSecurities
Namespace Prefix: | mpx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the maturity period of marketable securities. + References No definition available. + Details
Name: | mpx_PeriodOfMaturityOfMarketableSecurities
Namespace Prefix: | mpx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Describe the approximate term of the non-current marketable securities. + References No definition available. + Details
Name: | mpx_PeriodOfNonCurrentMarketableSecurities
Namespace Prefix: | mpx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration