Derivative Financial Instruments and Fair Value of Financial Instruments (Details) In Thousands, unless otherwise specified	Mar. 31, 2012 2012 [Member]	Mar. 31, 2012 2012 [Member] MXN	Dec. 31, 2011 2012 [Member] MXN	Mar. 31, 2012 2013 [Member]	Mar. 31, 2012 2013 [Member] MXN	Mar. 31, 2012 2014 [Member]	Mar. 31, 2012 2014 [Member] MXN	Mar. 31, 2012 Thereafter [Member]	Mar. 31, 2012 Thereafter [Member] MXN	Mar. 31, 2012 Palmarejo gold production royalty [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Palmarejo gold production royalty [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Palmarejo gold production royalty [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Palmarejo gold production royalty [Member] Thereafter [Member] USD ($) oz	Mar. 31, 2012 Mexican peso forward purchase contracts [Member] 2012 [Member] USD ($)	Mar. 31, 2012 Mexican peso forward purchase contracts [Member] 2013 [Member] USD ($)	Mar. 31, 2012 Mexican peso forward purchase contracts [Member] 2014 [Member] USD ($)	Mar. 31, 2012 Mexican peso forward purchase contracts [Member] Thereafter [Member] USD ($)	Mar. 31, 2012 Mexican Peso Notional Amount [Member] 2012 [Member] oz	Mar. 31, 2012 Mexican Peso Notional Amount [Member] 2013 [Member] oz	Mar. 31, 2012 Mexican Peso Notional Amount [Member] 2014 [Member] oz	Mar. 31, 2012 Mexican Peso Notional Amount [Member] Thereafter [Member] oz	Mar. 31, 2012 Silver ounces received from Mandalay [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Silver ounces received from Mandalay [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Silver ounces received from Mandalay [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Silver ounces received from Mandalay [Member] Thereafter [Member] USD ($) oz	Mar. 31, 2012 Silver concentrate sales agreements [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Silver concentrate sales agreements [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Silver concentrate sales agreements [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Silver concentrate sales agreements [Member] Thereafter [Member] USD ($) oz	Mar. 31, 2012 Gold concentrates sales agreements [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Gold concentrates sales agreements [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Gold concentrates sales agreements [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Gold concentrates sales agreements [Member] Thereafter [Member] USD ($) oz	Mar. 31, 2012 Gold put options purchased [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Gold put options purchased [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Gold put options purchased [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Gold put options purchased [Member] Thereafter [Member] USD ($) oz	Mar. 31, 2011 Gold call options sold [Member] oz	Mar. 31, 2012 Gold call options sold [Member] 2012 [Member] USD ($) oz	Mar. 31, 2012 Gold call options sold [Member] 2013 [Member] USD ($) oz	Mar. 31, 2012 Gold call options sold [Member] 2014 [Member] USD ($) oz	Mar. 31, 2012 Gold call options sold [Member] Thereafter [Member] USD ($) oz
Derivative instruments Settlement
Derivative, Notional Amount										$ 20,784	$ 25,097	$ 24,895	$ 48,337									$ 1,152	$ 0	$ 0	$ 0	$ 10,689	$ 0	$ 0	$ 0	$ 5,500	$ 0	$ 0	$ 0	$ 2,160	$ 1,800	$ 720	$ 0		$ 0	$ 1,800	$ 720	$ 0
Derivative average gold price in excess of minimum contractual Deduction Rate										499	502	498	492
Fair value of foreign exchange contracts														$ 25,800	$ 0	$ 0	$ 0
Average rate (MXP/$)		12.78	0		0.00		0		0
Average forward price																						18.43	0	0	0
Derivative average price																						31.71	0	0	0					1,729.00	0	0	0
Average strike price	2,000.00	2,000.00		1,827.00	1,827.00	1,934.00	1,934.00	2,000.00	2,000.00																									923.00	928.00	979.00	1,010.00	1,723.11
Notional ounces										41,670	50,004	50,004	98,296					329,603	0	0	0	62,500	0	0	0	337,058	0	0	0	3,181	0	0	0	51,000	45,000	47,000	30,000	11,250	14,000	45,000	47,000	30,000