Derivative Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	$ 16,105	$ (20,646)	$ (3,611)	$ 63,905
Fair value adjustments, net	11,076	(17,664)	(6,558)	64,963
Concentrate Sales Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Sales of Metals	(684)	718	(188)	(2,037)
Forward foreign exchange contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Costs applicable to sales	0	(99)	924	(732)
Fair value adjustments, net	(57)	100	901	(1,422)
Mexican peso forward purchase contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	(57)	100	901	(1,422)
Palmarejo gold production royalty [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	8,736	(15,279)	(6,560)	60,216
Silver and gold options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net	$ 3,081	$ (3,104)	$ 213	$ 7,474