Business, Product and Geographical Area Information and Concentration of Risk, Narrative (Details) - productionfacilities	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information
Percentage of employees covered by collective bargaining agreements	62.00%		62.00%
Percentage of employees covered by collective bargaining agreements expiring within one year	1.00%		1.00%
Domestic
Segment Reporting Information
Number of production facilities			12
Foreign
Segment Reporting Information
Number of production facilities			1
Customer Concentration Risk | Largest Customer | Sales Revenue, Net
Segment Reporting Information
Concentration percentages (percent)	26.00%	27.00%	25.00%	27.00%
Customer Concentration Risk | Largest Customer | Accounts Receivable
Segment Reporting Information
Concentration percentages (percent)			23.00%		31.00%
Customer Concentration Risk | Second Largest Customer | Sales Revenue, Net
Segment Reporting Information
Concentration percentages (percent)	14.00%	11.00%	14.00%	12.00%
Customer Concentration Risk | Second Largest Customer | Accounts Receivable
Segment Reporting Information
Concentration percentages (percent)			13.00%		11.00%