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Derivative Financial Instruments - Additional Information (Detail)
6 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
Dec. 31, 2018
$ / shares
Dec. 31, 2017
$ / shares
Derivatives, Fair Value [Line Items]      
Derivative instruments objectives We use derivatives to partially offset our exposure to foreign currency, interest rate, aluminum and other commodity price risk. We may enter into forward contracts, option contracts, swaps, collars or other derivative instruments to offset some of the risk on expected future cash flows and on certain existing assets and liabilities.    
Maximum length of time, foreign currency cash flow hedge 48 months    
Par or stated value per share | $ / shares $ 0.01 $ 0.01 $ 0.01
Convertible Preferred Stock, Redemption Value | $ $ 300,000,000    
Price Volatility [Member]      
Derivatives, Fair Value [Line Items]      
Dividend yield rate 0.550    
Expected Dividend Rate [Member]      
Derivatives, Fair Value [Line Items]      
Dividend yield rate 0.104    
Minimum [Member] | Expected Term [Member]      
Derivatives, Fair Value [Line Items]      
Valuation scenario term 2 years 6 months    
Minimum [Member] | Risk Free Interest Rate [Member]      
Derivatives, Fair Value [Line Items]      
Dividend yield rate 0.017    
Maximum [Member] | Expected Term [Member]      
Derivatives, Fair Value [Line Items]      
Valuation scenario term 6 years 2 months 15 days    
Maximum [Member] | Risk Free Interest Rate [Member]      
Derivatives, Fair Value [Line Items]      
Dividend yield rate 0.018    
Embedded derivative liability [Member]      
Derivatives, Fair Value [Line Items]      
Redemption per share | $ / shares $ 56.32    
Par or stated value per share | $ / shares $ 19.05    
Debt instrument face value | $ $ 150,000,000    
Convertible Preferred Stock, Redemption Value | $ $ 300,000,000    
Risky bond rate 20.90%