Mining Properties (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Mining Properties
Operational mining properties:	$ 899,424	$ 804,845
Accumulated depletion	(518,075)	(485,368)
Operational mining properties, net	381,349	319,477
Mineral interest	974,512	969,341
Accumulated depletion	(490,818)	(459,249)
Mineral interest, net	483,694	510,092
Total mining properties	865,043	829,569
Palmarejo [Member]
Mining Properties
Operational mining properties:	233,562	214,383
Accumulated depletion	(159,120)	(146,598)
Operational mining properties, net	74,442	67,785
Mineral interest	629,303	629,303
Accumulated depletion	(463,565)	(435,215)
Mineral interest, net	165,738	194,088
Total mining properties	240,180	261,873
Rochester [Member]
Mining Properties
Operational mining properties:	196,143	193,881
Accumulated depletion	(149,729)	(144,390)
Operational mining properties, net	46,414	49,491
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Total mining properties	46,414	49,491
Silvertip [Member]
Mining Properties
Operational mining properties:	105,320	57,214
Accumulated depletion	(389)	0
Operational mining properties, net	104,931	57,214
Mineral interest	245,116	245,116
Accumulated depletion	(988)	0
Mineral interest, net	244,128	245,116
Total mining properties	349,059	302,330
Kensington [Member]
Mining Properties
Operational mining properties:	322,901	298,749
Accumulated depletion	(191,026)	(178,632)
Operational mining properties, net	131,875	120,117
Mineral interest	0	0
Accumulated depletion	0	0
Mineral interest, net	0	0
Total mining properties	131,875	120,117
Wharf [Member]
Mining Properties
Operational mining properties:	41,498	40,618
Accumulated depletion	(17,811)	(15,748)
Operational mining properties, net	23,687	24,870
Mineral interest	45,837	45,837
Accumulated depletion	(25,843)	(24,034)
Mineral interest, net	19,994	21,803
Total mining properties	43,681	46,673
La Preciosa [Member]
Mining Properties
Operational mining properties:	0	0
Accumulated depletion	0	0
Operational mining properties, net	0	0
Mineral interest	49,085	49,085
Accumulated depletion	0	0
Mineral interest, net	49,085	49,085
Total mining properties	49,085	$ 49,085
Other Mining Properties [Member]
Mining Properties
Operational mining properties:	0
Accumulated depletion	0
Operational mining properties, net	0
Mineral interest	5,171
Accumulated depletion	(422)
Mineral interest, net	4,749
Total mining properties	$ 4,749