Segment Reporting (Details Textual) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Reporting (Textual) [Abstract]
Total Revenue	$ 231,090	$ 101,018	$ 430,714	$ 189,307
Silver [Member]
Segment Reporting (Textual) [Abstract]
Total Revenue	158,800	73,300	271,300	133,300
Gold [Member]
Segment Reporting (Textual) [Abstract]
Total Revenue	$ 72,300	$ 27,700	$ 159,400	$ 56,000