Segment Reporting (Details 2) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) trading_counterparty	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	$ 787,986	$ 729,103
Revenues
Revenue	646,086	635,742	$ 745,994
United States [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	336,210	275,594
Revenues
Revenue	376,692	260,728	268,023
Mexico [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	390,694	298,101
Revenues
Revenue	171,911	245,493	324,040
BOLIVIA
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	35,201	107,960
Revenues
Revenue	84,679	117,749	141,721
Australia [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	5,952	21,362
Revenues
Revenue	8,732	10,046	12,871
Argentina [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	10,871	10,970
Other Foreign Countries [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	9,058	15,116
Revenues
Revenue	4,072	1,726	(661)
Mitsui & Co. [Member]
Revenues
Revenue	137,700	133,800	70,300
China National Gold [Domain]
Revenues
Revenue	126,200	86,800	81,500
Asahi Formerly Johnson Matthey [Member]
Revenues
Revenue	84,200	71,800	66,400
TD Securities [Domain]
Revenues
Revenue	81,300	106,700	106,700
Standard Bank [Domain]
Revenues
Revenue	34,700	87,500	69,000
INTL Commodities [Member]
Revenues
Revenue	33,100	22,400	84,600
Valcambi [Member]
Revenues
Revenue	0	33,900	77,200
Auramet [Member]
Revenues
Revenue	$ 0	$ 10,800	$ 111,700
Smelting and Refining [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of Trading Counterparties | trading_counterparty	3
Dore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of Trading Counterparties | trading_counterparty	11
Sales [Member] | Smelting and Refining [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	26.00%	37.00%	28.00%
Sales [Member] | Dore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage	74.00%	63.00%	72.00%