Mining Properties (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Mining Property [Abstract]
Operational mining properties:	$ 649,936	$ 622,361
Accumulated depletion	(203,416)	(149,211)
Operational mining properties, net	446,490	473,150
Mineral interest	1,729,064	1,727,863
Accumulated depletion	(174,668)	(78,939)
Mineral interest, net	1,554,396	1,648,924
Non-producing and developmental properties(B)	142	142
Total mining properties	2,001,027	2,122,216
San Bartolome [Member]
Mining Property [Abstract]
Operational mining properties:	68,684	66,655
Accumulated depletion	(14,989)	(10,031)
Operational mining properties, net	53,695	56,624
Mineral interest	26,642	26,642
Accumulated depletion	(6,007)	(4,027)
Mineral interest, net	20,635	22,615
Non-producing and developmental properties(B)	0	0
Total mining properties	74,330	79,239
Martha [Member]
Mining Property [Abstract]
Operational mining properties:	12,644	10,096
Accumulated depletion	(10,373)	(9,998)
Operational mining properties, net	2,271	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	2,271	98
Palmarejo [Member]
Mining Property [Abstract]
Operational mining properties:	134,296	128,734
Accumulated depletion	(53,060)	(22,655)
Operational mining properties, net	81,236	106,079
Mineral interest	1,658,389	1,657,188
Accumulated depletion	(158,627)	(68,026)
Mineral interest, net	1,499,762	1,589,162
Non-producing and developmental properties(B)	0	0
Total mining properties	1,580,998	1,695,241
Rochester [Member]
Mining Property [Abstract]
Operational mining properties:	115,163	99,720
Accumulated depletion	(97,834)	(97,435)
Operational mining properties, net	17,329	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	2,004,988	2,285
Endeavor [Member]
Mining Property [Abstract]
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	44,033	44,033
Accumulated depletion	(10,034)	(6,886)
Mineral interest, net	33,999	37,147
Non-producing and developmental properties(B)	0	0
Total mining properties	33,999	37,147
Kensington [Member]
Mining Property [Abstract]
Operational mining properties:	321,456	317,156
Accumulated depletion	(27,160)	(9,092)
Operational mining properties, net	294,296	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	294,296	308,064
Other [Member]
Mining Property [Abstract]
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	0	0
Non-producing and developmental properties(B)	142	142
Total mining properties	$ 142	$ 142