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Segment Reporting - Summary of Percentage of Revenues from Major Customers (Detail) - Net sales
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Ford      
Revenue, Major Customer [Line Items]      
Concentration risk percentage 18.30% 21.00% 22.50%
General Motors      
Revenue, Major Customer [Line Items]      
Concentration risk percentage 18.00% 20.90% 20.00%
BMW      
Revenue, Major Customer [Line Items]      
Concentration risk percentage 8.10% 10.10% 10.50%