Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Significant Unobservable Inputs to Level 3) (Details)

v2.4.1.9
Fair Value Measurements (Significant Unobservable Inputs to Level 3) (Details)
 6 Months Ended 12 Months Ended
Dec. 31, 2014
Jun. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Rolling gross production average 60 days  
Discounted cash flow model | Contingent consideration payable | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Discount rate 8.00%us-gaap_FairValueInputsDiscountRate
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByLiabilityClassAxis
= mpet_ContingentConsiderationMember
/ us-gaap_ValuationTechniqueAxis
= us-gaap_MarketApproachValuationTechniqueMember 		8.00%us-gaap_FairValueInputsDiscountRate
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByLiabilityClassAxis
= mpet_ContingentConsiderationMember
/ us-gaap_ValuationTechniqueAxis
= us-gaap_MarketApproachValuationTechniqueMember