Mining Properties (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Mining Properties
Operational mining properties:	$ 641,250	$ 622,361
Accumulated depletion	(190,890)	(149,211)
Operational mining properties, net	450,360	473,150
Mineral interest	1,727,863	1,727,863
Accumulated depletion	(147,222)	(78,939)
Mineral interest, net	1,580,641	1,648,924
Non-producing and developmental properties(B)	142	142
Total mining properties	2,031,143	2,122,216
Palmarejo [Member]
Mining Properties
Operational mining properties:	133,223	128,734
Accumulated depletion	(45,287)	(22,655)
Operational mining properties, net	87,936	106,079
Mineral interest	1,657,188	1,657,188
Accumulated depletion	(132,449)	(68,026)
Mineral interest, net	1,524,739	1,589,162
Non-producing and developmental properties(B)	0	0
Total mining properties	1,612,675	1,695,241
San Bartolome [Member]
Mining Properties
Operational mining properties:	66,848	66,655
Accumulated depletion	(13,694)	(10,031)
Operational mining properties, net	53,154	56,624
Mineral interest	26,642	26,642
Accumulated depletion	(5,490)	(4,027)
Mineral interest, net	21,152	22,615
Non-producing and developmental properties(B)	0	0
Total mining properties	74,306	79,239
Kensington [Member]
Mining Properties
Operational mining properties:	320,943	317,156
Accumulated depletion	(24,407)	(9,092)
Operational mining properties, net	296,536	308,064
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Non-producing and developmental properties(B)	0	0
Total mining properties	296,536	308,064
Rochester [Member]
Mining Properties
Operational mining properties:	108,741	99,720
Accumulated depletion	(97,435)	(97,435)
Operational mining properties, net	11,306	2,285
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Non-producing and developmental properties(B)	0	0
Total mining properties	11,306	2,285
Martha [Member]
Mining Properties
Operational mining properties:	11,495	10,096
Accumulated depletion	(10,067)	(9,998)
Operational mining properties, net	1,428	98
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Non-producing and developmental properties(B)	0	0
Total mining properties	1,428	98
Endeavor [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	44,033	44,033
Accumulated depletion	(9,283)	(6,886)
Mineral interest, net	34,750	37,147
Non-producing and developmental properties(B)	0	0
Total mining properties	34,750	37,147
Other Mining Properties [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	142	0
Non-producing and developmental properties(B)	0	142
Total mining properties	$ 142	$ 142