Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation (Details)

v2.4.1.9
Basis of Presentation (Details) (USD $)
3 Months Ended 9 Months Ended
Mar. 31, 2015
Mar. 31, 2015
segment
Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]      
Impairment on AFS securities $ 168,000us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities $ 168,000us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities $ 0us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities
Number of reportable segments   3us-gaap_NumberOfReportableSegments  
Utah CO2 LLC      
Schedule of Equity Method Investments [Line Items]      
Majority interest percentage 51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_UtahCO2LLCMember
51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_UtahCO2LLCMember
 
Central Petroleum Limited      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage 11.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_CentralPetroleumLimitedMember
11.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_CentralPetroleumLimitedMember
 
Two separate third parties | Utah CO2 LLC      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage 49.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= mpet_TwoSeparateThirdPartiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_UtahCO2LLCMember
49.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= mpet_TwoSeparateThirdPartiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= mpet_UtahCO2LLCMember