Impairment of Long Lived Assets (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended					6 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Velardena Operations Asset Group	Jun. 30, 2013 Velardena Operations Asset Group Mineral properties	Jun. 30, 2013 Velardena Operations Asset Group Exploration properties	Jun. 30, 2013 Velardena Operations Asset Group Tangible assets	Jun. 30, 2013 San Diego exploration property	Jun. 30, 2013 San Diego exploration property km	Sep. 02, 2011 San Diego exploration property	Jun. 30, 2013 San Diego exploration property Exploration properties	Jun. 30, 2013 Gold	Jun. 30, 2013 Silver
Impaired Long-Lived Assets Held and Used [Line Items]
Decrease in metal prices (as a percent)													26.00%	34.00%
Net deferred tax asset (liability)					$ 0
Income Tax Expense (Benefit)	(45,017,000)	(1,189,000)	(47,495,000)	(2,960,000)	(45,000,000)
Details of components of the impairment of long lived assets
Net Book Value Prior to Impairment					260,387,000	232,805,000	3,472,000	24,110,000	9,260,000			9,260,000
Impairment Charges	238,020,000		238,020,000		229,593,000	211,609,000	3,472,000	14,512,000	8,428,000			8,428,000
Net Book Value After Impairment					30,794,000	21,196,000		9,598,000	832,000	832,000		832,000
Percentage of ownership interest										50.00%
Distance of exploration property from other operations										10
Purchase price											$ 9,300,000