XML 26 R27.htm IDEA: XBRL DOCUMENT v3.20.1

MARKETABLE SECURITIES (Tables)

3 Months Ended

Mar. 31, 2020

MARKETABLE SECURITIES

Schedule of net realized (losses) gains and reclassification of net realized (losses) gains from other comprehensive income

​

​	​	​	​	​	​	​
​	​	Three months ended
​	​	March 31,
(in thousands)		2020			2019
Net realized gain	​	$	—	​	$	4
Reclassification of net realized gains from other comprehensive income	​	$	—	​	$	4

X

- Definition

Tabular disclosure of net realized gains and the reclassification of net realized gains from other comprehensive income.

+ References

No definition available.

+ Details

Name:	mpx_ScheduleOfNetRealizedGainLossAndReclassificationTableTextBlock
Namespace Prefix:	mpx_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

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