Derivative Financial Instruments (Details 2) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Costs applicable to sales	[1]	$ 100,465	[2]	$ 119,097	[3]	$ 202,020	[4]	$ 234,160	[5]
Fair value adjustments, net		(3,579)		2,754		(12,274)		(2,130)
Fair value adjustments, net		(295)		994		(6,175)		(684)
Concentrate Sales Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives		597		(623)		1,163		291
Embedded Derivative Financial Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net		(878)		385		(5,756)		(1,160)
Silver and gold options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives		0		1,200		0		1,000
Fair value adjustments, net		$ (14)		$ 1,232		$ (1,582)		$ 185

[1] Excludes amortization.

[2] Segment assets include receivables, prepaids, inventories, property, plant and equipment, and mineral interest

[3] Excludes amortization

[4] Excludes amortization

[5] Excludes amortization