Mining Properties (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Mining Properties
Operational mining properties:	$ 671,175		$ 649,905
Accumulated depletion	(229,891)		(203,416)
Operational mining properties, net	441,284		446,489
Mineral interest	1,729,064	[1]	1,729,064	[1]
Accumulated depletion	(224,727)		(174,668)
Mineral interest, net	1,504,337		1,554,396
Non-producing and developmental properties(B)	142		142
Total mining properties	1,945,763		2,001,027
Palmarejo [Member]
Mining Properties
Operational mining properties:	147,873		134,296
Accumulated depletion	(68,750)		(53,060)
Operational mining properties, net	79,123		81,236
Mineral interest	1,658,389	[1]	1,658,389	[1]
Accumulated depletion	(204,781)		(158,627)
Mineral interest, net	1,453,608		1,499,762
Non-producing and developmental properties(B)	0		0
Total mining properties	1,532,731		1,580,998
San Bartolome [Member]
Mining Properties
Operational mining properties:	69,671		68,684
Accumulated depletion	(16,716)		(14,989)
Operational mining properties, net	52,955		53,695
Mineral interest	26,642	[1]	26,642	[1]
Accumulated depletion	(6,676)		(6,007)
Mineral interest, net	19,966		20,635
Non-producing and developmental properties(B)	0		0
Total mining properties	72,921		74,330
Kensington [Member]
Mining Properties
Operational mining properties:	328,786		321,456
Accumulated depletion	(33,878)		(27,160)
Operational mining properties, net	294,908		294,296
Mineral interest	0	[1]	0	[1]
Accumulated depletion	0		0
Mineral interest, net	0		0
Non-producing and developmental properties(B)	0		0
Total mining properties	294,908		294,296
Rochester [Member]
Mining Properties
Operational mining properties:	113,429		112,826
Accumulated depletion	(99,131)		(97,834)
Operational mining properties, net	14,298		14,992
Mineral interest	0	[1]	0	[1]
Accumulated depletion	0		0
Mineral interest, net	0		0
Non-producing and developmental properties(B)	0		0
Total mining properties	14,298		14,992
Martha [Member]
Mining Properties
Operational mining properties:	11,416		12,643
Accumulated depletion	(11,416)		(10,373)
Operational mining properties, net	0		2,270
Mineral interest	0	[1]	0	[1]
Accumulated depletion	0		0
Mineral interest, net	0		0
Non-producing and developmental properties(B)	0		0
Total mining properties	0		2,270
Endeavor [Member]
Mining Properties
Operational mining properties:	0		0
Accumulated depletion	0		0
Operational mining properties, net	0		0
Mineral interest	44,033	[1]	44,033	[1]
Accumulated depletion	(13,270)		(10,034)
Mineral interest, net	30,763		33,999
Non-producing and developmental properties(B)	0		0
Total mining properties	30,763		33,999
Other Mining Properties [Member]
Mining Properties
Operational mining properties:	0		0
Accumulated depletion	0		0
Operational mining properties, net	0		0
Mineral interest	0	[1]	0	[1]
Accumulated depletion	0		0
Mineral interest, net	0		0
Non-producing and developmental properties(B)	142		142
Total mining properties	$ 142		$ 142

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