Balance Sheet Related Information (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Reclamation liability
Balance at beginning of the year	$ 9.3	$ 8.0
Settlement of obligations	(3.9)	(4.3)
Liabilities incurred and accretion expense	4.2	6.0
Currency translation adjustments	(0.1)	(0.4)
Balance at the end of the year	$ 9.5	$ 9.3