Mining Properties (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Mining Properties
Operational mining properties:	$ 667,612	$ 641,305
Accumulated depletion	(354,142)	(315,541)
Operational mining properties, net	313,470	325,764
Mineral interest	1,774,724	1,753,129
Accumulated depletion	(358,266)	(327,392)
Mineral interest, net	1,416,458	1,425,737
Total mining properties	1,729,928	1,751,501
Palmarejo [Member]
Mining Properties
Operational mining properties:	163,662	151,845
Accumulated depletion	(118,939)	(110,143)
Operational mining properties, net	44,723	41,702
Mineral interest	1,146,572	1,146,572
Accumulated depletion	(325,348)	(300,187)
Mineral interest, net	821,224	846,385
Total mining properties	865,947	888,087
San Bartolome [Member]
Mining Properties
Operational mining properties:	70,862	70,761
Accumulated depletion	(25,114)	(22,236)
Operational mining properties, net	45,748	48,525
Mineral interest	26,643	26,643
Accumulated depletion	(9,797)	(8,759)
Mineral interest, net	16,846	17,884
Total mining properties	62,594	66,409
Kensington [Member]
Mining Properties
Operational mining properties:	279,112	268,351
Accumulated depletion	(99,578)	(80,032)
Operational mining properties, net	179,534	188,319
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Total mining properties	179,534	188,319
Rochester [Member]
Mining Properties
Operational mining properties:	153,976	150,348
Accumulated depletion	(110,511)	(103,130)
Operational mining properties, net	43,465	47,218
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Total mining properties	43,465	47,218
Endeavor [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	420,417	408,352
Accumulated depletion	0	0
Mineral interest, net	420,417	408,352
Total mining properties	420,417	408,352
Joaquin Project - Argentina [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	93,429	93,429
Accumulated depletion	0	0
Mineral interest, net	93,429	93,429
Total mining properties	93,429	93,429
Other Mining Properties [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	87,663	78,133
Accumulated depletion	(23,121)	(18,446)
Mineral interest, net	64,542	59,687
Total mining properties	$ 64,542	$ 59,687