Derivative Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Revenue	$ 152,956		$ 159,633
Costs applicable to sales	115,062	[1]	106,896	[1]
Fair value adjustments, net	(4,884)		(11,436)
Fair value adjustments, net	(1,677)		(10,808)
Concentrate Sales Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	914		879
Forward foreign exchange contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Costs applicable to sales	0		(924)
Fair value adjustments, net	0		968
Mexican peso forward purchase contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	0		968
Palmarejo gold production royalty [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	(1,545)		(10,237)
Silver and gold options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	200		(1,494)
Fair value adjustments, net	$ (1,046)

[1] Excludes amortization.