Business, Product and Geographical Area Information and Concentration of Risk - Schedules of Concentration of Risk, by Risk Factor (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Export sales | Net sales
Concentration Risk
Concentration risk, percentage	15.00%	18.00%	19.00%
Supplier concentration risk | Aluminum | Top five major suppliers
Concentration Risk
Concentration risk, percentage	81.00%	85.00%	84.00%
Supplier concentration risk | Aluminum | Largest supplier
Concentration Risk
Concentration risk, percentage	22.00%	36.00%	32.00%
Supplier concentration risk | Aluminum | Second and third largest suppliers
Concentration Risk
Concentration risk, percentage	38.00%	33.00%	32.00%
Largest Customer [Member] | Customer Concentration Risk [Member] | Trade receivables
Concentration Risk
Concentration risk, percentage	31.00%	22.00%
Second Largest Customer [Member] | Customer Concentration Risk [Member] | Trade receivables
Concentration Risk
Concentration risk, percentage	11.00%	14.00%