Derivative Financial Instruments and Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	$ 16,039	$ (12,432)	$ (7,074)	$ (17,700)
Fair value adjustments, net	14,011	(13,088)	(8,549)	(19,462)
Concentrate Sales Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Sales of Metals	(877)	(1,515)	459	(2,873)
Forward foreign exchange contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Production costs applicable to sales	(1,151)	859	(1,934)	1,111
Fair value adjustments	83	(707)	2,773	298
Gold lease facility [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	0	0	0	(132)
Forward gold contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	0	0	0	35
Silver Ounces Receivables [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	(337)	(368)	22	464
Palmarejo gold production royalty [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	14,106	(13,731)	(11,505)	(20,041)
Put and call options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments	$ 2,187	$ 2,374	$ 1,636	$ 1,676