XML 50 R37.htm IDEA: XBRL DOCUMENT v3.3.1.900

SIGNIFICANT ACCOUNTING POLICIES (Detail Textuals 3)	12 Months Ended
	Dec. 31, 2015
Municipal debt obligations | AA- or higher
Schedule of Available-for-sale Securities [Line Items]
Period of maturity debt obligations	less than one year to over 10 years
Municipal debt obligations | A- or higher
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	2017 and 2037
Corporate obligations | A- or higher
Schedule of Available-for-sale Securities [Line Items]
Period of maturity debt obligations	one to five 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

X

- 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

- Definition

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.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_DebtSecurityAxis=us-gaap_MunicipalNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CreditRatingStandardPoorsAxis=mpx_StandardPoorsAAMinusOrHigherRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CreditRatingStandardPoorsAxis=mpx_StandardPoorsAMinusOrHigherRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtSecurityAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: