ACQUISITIONS (Details) (USD $)	3 Months Ended	0 Months Ended	3 Months Ended			0 Months Ended
	Sep. 30, 2012	Sep. 03, 2012 Mt. Milligan	Sep. 30, 2012 Mt. Milligan	Aug. 08, 2012 Mt. Milligan	Jul. 31, 2012 Mt. Milligan	Aug. 15, 2012 Milligan III Acquisition	Aug. 08, 2012 Milligan III Acquisition
Acquisition of Royalty Interest in Mineral Properties
Percentage of payable ounces of gold purchased				52.25%			12.25%
Total purchase amount				$ 781,500,000	$ 581,500,000		$ 200,000,000
Cash payment for each payable ounce of gold (in dollars per ounce)				435
Cash paid for acquisition of royalty interests	120,035,000	45,000,000				75,000,000
Total cash paid on pre-production commitment			574,600,000
Future scheduled payments due for fourth quarter in calendar year 2012			95,000,000
Future scheduled payments due for first quarter in calendar year 2013			62,000,000
Future scheduled payments due for second quarter in calendar year 2013			37,000,000
Future scheduled payments due for third quarter in calendar year 2013			$ 12,900,000