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Equity - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
 0 Months Ended 3 Months Ended 0 Months Ended
Feb. 14, 2014
Mar. 31, 2015
Apr. 20, 2015
Dec. 31, 2014
Equity [Line Items]        
Owners Equity   29,655,804us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding   29,166,112us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding
Limited partnership interest   98.80%us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest    
Distribution to unitholders, payment date Feb. 13, 2015      
Distributions        
Equity [Line Items]        
Cash distribution     $ 0.125us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		  
Cash distribution on annualized basis     $ 0.50mcep_DistributionMadeToLimitedPartnerDistributionsPaidPerUnitAnnualizedBasis
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		  
Distribution to unitholders, payment date     May 14, 2015  
Distribution to unitholders, record date     May 07, 2015  
Distribution to holders     $ 3.7us-gaap_DistributionMadeToLimitedPartnerCashDistributionsDeclared
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember