Sales (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Sales [Line Items]
Platinum group metals purity percentage			99.95%
Rhodium purity percentage			99.90%
Revenues from by-product sales	$ 7.2	$ 8.0	$ 16.4	$ 15.5
General Motors Corporation [Member]
Sales [Line Items]
Supply agreement term (in years)	3		3
Tiffany & Co. [Member]
Sales [Line Items]
Supply agreement term (in years)	1		1