Significant Customers (Details Textual)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Significant Customers (Textual) [Abstract]
Approximate percentage of sales of metals to counterparties companies related to metal sales	82.00%	83.00%	83.00%
Approximate percentage of sales of silver concentrates to third-party smelters related to metal sales	18.00%	17.00%	17.00%