Inventories Inventories (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Finished goods		$ 345,779	$ 308,462
Raw materials and work in process	[1]	135,480	144,886
Stores, supplies and other		49,971	55,380
Total inventories		$ 531,230	$ 508,728

[1] Includes $41.0 million and $39.1 million at March 31, 2016 and December 31, 2015, respectively, of work in process related to the Lithium product category.