Balance Sheet Related Information (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reclamation liability
Balance at beginning of the year	$ 9,256	$ 7,529	$ 6,584
Settlement of obligations	(4,304)	(2,185)
Liabilities incurred and accretion expense	6,454	3,020
Currency translation adjustments	(423)	110
Balance at the end of the year	$ 9,256	$ 7,529	$ 6,584