Inventories, Net Summary of Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Finished products	$ 34,854	$ 24,424
In-process	13,862	10,310
Raw materials	23,871	12,346
Fine and fabricated precious metal in various stages of completion	20,432	17,094
Inventory, before LIFO reserve	93,019	64,174
LIFO reserve	(92)	(90)
Inventory, Net	$ 92,927	$ 64,084