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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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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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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
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Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

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Data Type:	num:percentItemType
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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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

Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

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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.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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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
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of cash inflow for proceeds from settlement of corporate-owned life insurance policy, classified as investing activities. Includes, but is not limited to, bank-owned life insurance policy.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Name:	us-gaap_ProceedsFromLifeInsurancePolicies
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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
-Publisher FASB
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Name:	us-gaap_TaxEffectOfExtraordinaryItem
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Namespace Prefix:
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Namespace Prefix:
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