Segment Information Summarized Financial Information by Reportable Segments (Footnote) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Feb. 01, 2017
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	$ 52,801	$ 0
Jiangxi Jiangli New Materials Science and Technology Co. Ltd.
Segment Reporting Information [Line Items]
Inventory markup	23,000
Sales de Magnesio Ltda.
Segment Reporting Information [Line Items]
Percentage of Equity Interests Acquired			50.00%
Cost of goods sold
Segment Reporting Information [Line Items]
Restructuring and other, net	2,900
Cost of goods sold | Jiangxi Jiangli New Materials Science and Technology Co. Ltd.
Segment Reporting Information [Line Items]
Utilization of inventory markup	10,600
Selling, general and administrative expenses
Segment Reporting Information [Line Items]
Restructuring and other, net	4,200
Research and development expenses
Segment Reporting Information [Line Items]
Restructuring and other, net	5,800
Other (expenses) income, net
Segment Reporting Information [Line Items]
Asset retirement obligation charges	3,200
Loss on sale of properties	$ 2,100