v3.7.0.1
Debt - Additional Information - Credit Facilities (Detail)
€ in Millions
1 Months Ended 12 Months Ended
May 08, 2015
USD ($)
Dec. 12, 2014
Oct. 31, 2014
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
May 08, 2015
EUR (€)
Debt Instrument [Line Items]                
Payments on long-term debt         $ 13,200,000 $ 1,391,800,000 $ 1,952,000,000  
Fees paid to third parties           100,000 $ 45,400,000  
Term Loan Facility [Member]                
Debt Instrument [Line Items]                
Payments on long-term debt           10,000,000    
Amended Senior Credit Facility [Member]                
Debt Instrument [Line Items]                
Term loan facility | €               € 225.0
Fees paid to third parties $ 1,800,000              
Fees paid to third parties expensed         $ 1,600,000      
Amended Senior Credit Facility [Member] | United States of America, Dollars [Member]                
Debt Instrument [Line Items]                
Interest Rate, Effective Percentage         3.75%      
Interest Rate Terms         LIBOR, bearing a 1.00% floor, plus an applicable margin of 2.75%      
Term loan facility $ 1,072,600,000              
Percentage Of Term Loan Amount On Equal Quarterly Installments         0.25%      
Amended Senior Credit Facility [Member] | Euro Member Countries, Euro [Member]                
Debt Instrument [Line Items]                
Interest Rate, Effective Percentage         3.75%      
Interest Rate Terms         EURIBOR, bearing a 1.00% floor, plus an applicable margin of 2.75%      
Percentage Of Term Loan Amount On Equal Quarterly Installments         0.25%      
Original issuance discount of foreign currency denominated tranche, Percentage 0.50%             0.50%
Original issuance discount of foreign currency denominated tranche, Value $ 1,300,000              
Amended Senior Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]                
Debt Instrument [Line Items]                
Interest bearing rate, Floor 1.00%             1.00%
Interest bearing marginal rate to floor 2.75%             2.75%
Amended Senior Credit Facility [Member] | Eurodollar [Member]                
Debt Instrument [Line Items]                
Interest bearing rate, Floor 1.00%             1.00%
Interest bearing marginal rate to floor 2.75%             2.75%
Refinanced Term Loan Facility                
Debt Instrument [Line Items]                
Payments on long-term debt           $ 45,000,000    
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Covenant Description         The agreement governing the Senior Credit Facilities contains certain covenants that, among other things, require MPG Holdco to maintain a leverage ratio once revolver borrowings and letters of credit exceed 35% of aggregate revolving credit commitments as defined under the terms of the Senior Credit Facilities and to comply with customary affirmative and negative covenants.      
Maximum percentage of aggregate revolving credit commitments required under leverage ratio         35.00%      
Mandatory prepayment of term loan due in 2016         $ 0      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Maximum                
Debt Instrument [Line Items]                
Dividends payable         $ 30,000,000      
Debt instruments, covenants dividend restriction as percentage of cash proceeds from public offering common stock         6.00%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Term Loan Facility [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Face Amount     $ 1,350,000,000          
Maturity Year     2021          
Interest Rate, Effective Percentage             4.25%  
Frequency of Periodic Payment         quarterly installments      
Payments on long-term debt       $ 3,375,000        
Interest Rate Terms         Interest on the Term Loan Facility accrued at a rate equal to the London Interbank Offered Rate (“LIBOR”) rate (bearing a LIBOR floor of 1.00%) plus an applicable margin of 3.25% or a base rate that is the higher of the Federal Funds Rate (plus 0.50%), the U.S. prime rate as published in The Wall Street Journal, or LIBOR (plus 1.00%), plus an applicable margin of 2.25%, at Holdco’s option. Prior to the Company’s initial public offering on December 12, 2014, the applicable margin was 3.50% for LIBOR rate loans and 2.50% for base rate loans. The interest rate in effect as of December 31, 2014 was 4.25%.      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Term Loan Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]                
Debt Instrument [Line Items]                
Interest bearing rate, Floor         1.00%      
Interest bearing marginal rate to floor   3.50%     3.25%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Term Loan Facility [Member] | Federal Funds Rate [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor   2.50%     0.50%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Term Loan Facility [Member] | LIBOR Plus [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         1.00%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Term Loan Facility [Member] | Base Rate [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         2.25%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member]                
Debt Instrument [Line Items]                
Maturity Year     2019          
Line of Credit Facility, Maximum Borrowing Capacity     $ 250,000,000          
Line of Credit Facility, Expiration Period         5 years      
Line of credit         $ 0      
Current Borrowing Capacity         $ 236,800,000      
Line of Credit Facility, Interest Rate Description         Interest on the Revolving Credit Facility is accrued at a rate equal to the LIBOR rate plus an applicable margin of 3.25% or a base rate that is the higher of the Federal Funds Rate (plus 0.50%), the U.S. prime rate as published in The Wall Street Journal, or LIBOR (plus 1.00%), plus an applicable margin of 2.25%, at Holdco’s option. The applicable margin is based on a leverage ratio grid.      
Line of Credit Facility, Commitment Fee Description         Holdco pays fees with respect to the Revolving Credit Facility, including (i) an unused commitment fee of 0.50% or 0.375% based on a leverage ratio, (ii) fixed fees with respect to letters of credit of 3.25% per annum on the stated amount of each letter of credit outstanding during each month and (iii) customary administrative fees.      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | Minimum                
Debt Instrument [Line Items]                
Unused commitment fee, percentage         0.50%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | Maximum                
Debt Instrument [Line Items]                
Unused commitment fee, percentage         0.375%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         3.25%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | Federal Funds Rate [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         0.50%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | LIBOR Plus [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         1.00%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Revolving Credit Facility [Member] | Base Rate [Member]                
Debt Instrument [Line Items]                
Interest bearing marginal rate to floor         2.25%      
MPG Holdco I Inc. [Member] | Senior Credit Facilities [Member] | Letter of Credit [Member]                
Debt Instrument [Line Items]                
Unused commitment fee, percentage         3.25%