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Long-Term Debt and Notes Payable - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
1 Months Ended 12 Months Ended 6 Months Ended
Apr. 30, 2014
Dec. 31, 2014
Jun. 30, 2014
Dec. 31, 2013
Debt Instrument [Line Items]        
Letter of credit, first lien $ 950.0us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity      
Senior Notes [Member]        
Debt Instrument [Line Items]        
Issue of second-lien seven-year senior secured notes 500.0us-gaap_NotesIssued1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
500.0us-gaap_NotesIssued1
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
   
Tangible equity units, aggregate principal amount 47.5us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
40.5us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
   
Unsecured bilateral letters of credit [Member]        
Debt Instrument [Line Items]        
Letter of credit outstanding borrowings       96.9us-gaap_LineOfCredit
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Letter of Credit Facility [Member]        
Debt Instrument [Line Items]        
Letter of credit, first lien 400.0us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LetterOfCreditMember
     
Line of credit aggregate borrowing capacity   100.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LetterOfCreditMember
   
Term Loan [Member]        
Debt Instrument [Line Items]        
Letter of credit, first lien 300.0us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= mdr_TermLoanMember
     
Tangible Equity Units [Member]        
Debt Instrument [Line Items]        
Issue of tangible equity units 287.5mdr_TangibleShareholderEquity
/ us-gaap_CreditFacilityAxis
= mdr_TangibleEquityUnitsMember
     
Revolving Credit Facility [Member]        
Debt Instrument [Line Items]        
Unamortized issuance fees recognized as expenses     28.0us-gaap_InterestExpenseBorrowings
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
 
Line of credit aggregate borrowing capacity   950.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
   
Letter of credit outstanding borrowings   $ 214.3us-gaap_LineOfCredit
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember