Inventories Inventories (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished goods		$ 345,892	$ 289,102
Raw materials and work in process	[1]	120,759	109,706
Stores, supplies and other		52,285	51,455
Total inventories		$ 518,936	$ 450,263

[1] Included $50.1 million and $47.1 million at March 31, 2017 and December 31, 2016, respectively, of work in process related to the Lithium product category.