Acquisition of ECU Silver Mining Inc. (Details 3) (USD $)	12 Months Ended		1 Months Ended
	Dec. 31, 2011 Velardena Operations	Jun. 30, 2012 Velardena Operations	Sep. 30, 2011 ECU Silver Mining Inc.	Sep. 02, 2011 ECU Silver Mining Inc.	Sep. 02, 2011 ECU Silver Mining Inc. Term loan fund	Sep. 02, 2011 ECU Silver Mining Inc. Convertible note	Sep. 02, 2011 ECU Silver Mining Inc. Mineral properties	Sep. 02, 2011 ECU Silver Mining Inc. Asset retirement cost	Sep. 02, 2011 ECU Silver Mining Inc. Exploration properties	Sep. 02, 2011 ECU Silver Mining Inc. Plant and equipment
Allocation of purchase price
Current assets				$ 9,001,000
Inventories				1,520,000
Plant and equipment							239,200,000	1,883,000	12,732,000	14,059,000
Goodwill				70,155,000
Deferred tax asset				8,797,000
Current liabilities				(26,122,000)
Long term debt				(30,752,000)	(15,500,000)	(15,200,000)
Asset retirement obligation				(1,883,000)
Deferred tax liability				(65,511,000)
Total purchase price				233,079,000
Number of investment funds to whom loan is payable					2
Mexico corporate income tax rate (as a percent)			28.00%
Amount of estimated ARO and ARC	3,506,000
Third party estimated closure plan		$ 1,900,000