RESTRUCTURING ON ROYALTY INTERESTS IN MINERAL PROPERTIES (Details) (USD $) In Thousands, unless otherwise specified			1 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Aug. 31, 2011 Relief Canyon mile	Sep. 30, 2011 Relief Canyon
Restructuring on royalty interests in mineral properties
Royalty rate before reduction pursuant to the Amended and Restated Net Smelter Return Royalty Agreement (as a percent)			4.00%
Royalty rate pursuant to the Amended and Restated Net Smelter Return Royalty Agreement (as a percent)			2.00%
Area of interest eliminated pursuant to the Amended and Restated Net Smelter Return Royalty Agreement (in miles)			10
Restructuring	$ 1,328			$ 1,300
Carrying value for royalty interest	$ 1,671,943	$ 1,690,439		$ 1,200