Name:	mpx_DefinedBenefitPlanPercentageForNearTermBenefitPayments
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Percentage of investment for long term growth under the defined benefit plan. Percentage of investment for long term growth under the defined benefit plan.

No definition available.

Name:	mpx_DefinedBenefitPlanPercentageOfInvestmentForLongTermGrowth
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Data Type:	num:percentItemType
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This element represents the amount of trading gains (losses) of plan assets under the defined benefit plan.

No definition available.

Name:	mpx_DefinedBenefitPlanTradingGainsLosses
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This element represents the amount of variable life insurance policies included under the company-owned life insurance.

No definition available.

Name:	mpx_VariableLifeInsurancePoliciesInvestmentAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
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The pretax total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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Period Type:	instant

Amount of contributions made by the employer to defined benefit plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
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Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

Name:	us-gaap_DefinedBenefitPlanFundedStatusOfPlan
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Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

Name:	us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

This item represents the amount that could be realized under a life insurance contract or contracts owned by the Entity as of the date of the statement of financial position. Such Entity-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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The cash inflow for proceeds from life insurance policies for which the entity is the beneficiary.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Data Type:	xbrli:monetaryItemType
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The tax effect of gains and losses from events or transactions meeting the criteria of unusual in nature and infrequent in occurrence, thereby meeting the criteria to be classified as an extraordinary item.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Name:	us-gaap_TaxEffectOfExtraordinaryItem
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