Segment Reporting (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting (Textual) [Abstract]
Total Revenue	$ 168,847	$ 200,825	$ 204,525	$ 171,797	$ 205,929	$ 230,593	$ 254,406	$ 204,564	$ 745,994	$ 895,492	$ 1,021,200
Silver [Member]
Segment Reporting (Textual) [Abstract]
Total Revenue									394,500	549,700	662,600
Gold [Member]
Segment Reporting (Textual) [Abstract]
Total Revenue									$ 351,500	$ 345,800	$ 358,600
Metals [Member]
Segment Reporting (Textual) [Abstract]
Number of Trading Counterparties									5
Metals [Member] | Sales [Member]
Segment Reporting (Textual) [Abstract]
Concentration Risk, Percentage									72.00%	91.00%	82.00%
Gold and Silver [Member]
Segment Reporting (Textual) [Abstract]
Number of Trading Counterparties									8
Gold and Silver [Member] | Sales [Member]
Segment Reporting (Textual) [Abstract]
Concentration Risk, Percentage									28.00%	9.00%	18.00%