Balance Sheet Related Information - Reclamation Liability (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Reclamation liability [Abstract]
Balance at beginning of the year	$ 9.5	$ 9.3
Settlement of obligations	(3.2)	(3.9)
Liabilities incurred and accretion expense	3.1	4.2
Currency translation adjustments	(0.5)	(0.1)
Balance at the end of the year	$ 8.9	$ 9.5