Segment and Geographic Area Information Summarized Financial Information by Reportable Segments (Footnote) (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Feb. 01, 2017	Dec. 18, 2014	Dec. 08, 2014
Segment Reporting Information [Line Items]
Restructuring and other	$ 5,877	$ 3,838	$ 17,056
Gain on sale of property	(14,411)	0	0
Loss on early extinguishment of debt	4,829	0	52,801
Multiemployer plan, period contributions	1,400	1,500	1,500
Asset retirement obligation charges	3,600
Non-operating pension and OPEB items	26,970	5,285	(16,125)
Charitable contribution		15,000
Utilization of inventory markup			23,095
Repayments of long-term debt	175,215	0	778,209
Repayment of debt premium			45,200
Cost of goods sold
Segment Reporting Information [Line Items]
Restructuring and other		100	2,900
Non-routine Chilean labor costs	700	8,800
Write-off of fixed assets		4,900
Reversal of a liability from an abandoned project			1,300
Research and development expenses
Segment Reporting Information [Line Items]
Restructuring and other			5,700
Selling, general and administrative expenses
Segment Reporting Information [Line Items]
Restructuring and other	5,900	3,700	8,400
Gain on sale of property	(3,300)
Write-off of uncollectable accounts receivable	900
Settlement of terminated agreements	1,000
Revision of tax indemnification expense	800
Charitable contribution		1,200
Gain related to a refund form Chilean authorities		1,500
Reversal of purchase accounting accrual			1,000
Other expenses, net
Segment Reporting Information [Line Items]
Gain on sale of property	(11,100)		(8,700)
Revision of tax indemnification expense	9,800	19,700	3,700
Unrecoverable vendor costs	3,100
Asset retirement obligation charges	3,600		3,200
Revision of previously recorded expenses of a disposed business		5,500
Reversal of a liability from previous business		1,500	1,100
Settlement of a legal claim			1,000
Reversal of a liability from previous acquisition			10,600
Jiangxi Jiangli New Materials Science and Technology Co. Ltd. | Cost of goods sold
Segment Reporting Information [Line Items]
Utilization of inventory markup			23,100
Sales de Magnesio Ltda.
Segment Reporting Information [Line Items]
Percentage of equity interests acquired					50.00%
Financial Improvement Plan | Selling, general and administrative expenses
Segment Reporting Information [Line Items]
Multiemployer plan, period contributions	$ 1,800	$ 2,300	$ 3,300
Jordan Bromine Company Limited
Segment Reporting Information [Line Items]
Ownership percentage	50.00%
Jordan Bromine Company Limited | Other expenses, net
Segment Reporting Information [Line Items]
Non-operating pension and OPEB items	$ 1,200
Windfield Holdings
Segment Reporting Information [Line Items]
Ownership percentage	49.00%	49.00%	49.00%	49.00%
3.00% Senior Notes
Segment Reporting Information [Line Items]
Debt instrument, interest rate			3.00%	3.00%
1.875% Senior Notes
Segment Reporting Information [Line Items]
Debt instrument, interest rate	1.875%	1.875%	1.875%	1.875%		1.875%	1.875%
4.50% Senior Notes
Segment Reporting Information [Line Items]
Debt instrument, interest rate	4.50%	4.50%	4.50%	4.50%
Senior Notes | 3.00% Senior Notes
Segment Reporting Information [Line Items]
Repayments of long-term debt			$ 250,000
Senior Notes | 1.875% Senior Notes
Segment Reporting Information [Line Items]
Repayments of long-term debt | €				€ 307.0
Senior Notes | 4.50% Senior Notes
Segment Reporting Information [Line Items]
Repayments of long-term debt			$ 174,700