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MARKETABLE SECURITIES - Gross unrealized gains (losses) on marketable securities (Details 1) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2015 | Dec. 31, 2014
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Schedule of Available-for-sale Securities [Line Items] |  |
Gross unrealized Gains | $ 119 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI | $ 122 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI
Gross unrealized (Losses) | (12)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI | (37)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI
Municipal Obligations |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Gross unrealized Gains | 99 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_MunicipalNotesMember | 121 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_MunicipalNotesMember
Gross unrealized (Losses) | (10)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_MunicipalNotesMember | (31)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_MunicipalNotesMember
Corporate obligations |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Gross unrealized Gains | 20 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_CorporateDebtSecuritiesMember | 1 mpx_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_CorporateDebtSecuritiesMember
Gross unrealized (Losses) | $ (2)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_CorporateDebtSecuritiesMember | $ (6)mpx_AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInAOCI / us-gaap_DebtSecurityAxis = us-gaap_CorporateDebtSecuritiesMember

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- Definition Amount of accumulated pre-tax unrealized gains on investments in available-for-sale securities that are recognized in Accumulated Other Comprehensive Income (AOCI). + References No definition available. + Details
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Balance Type: | credit
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- Definition Amount of accumulated pre-tax unrealized loss before deducting unrealized gain on investments in available- for-sale securities recognized in Accumulated Other Comprehensive Income (AOCI). + References No definition available. + Details
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- Details
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- Details
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- Details
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