SUBSEQUENT EVENT (Details) (USD $)	12 Months Ended					1 Months Ended		1 Months Ended		1 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2012 Mt. Milligan	Dec. 14, 2011 Mt. Milligan	Aug. 31, 2012 Gold Stream Acquisition Mt. Milligan	Aug. 08, 2012 Gold Stream Acquisition Mt. Milligan	Aug. 31, 2012 Gold Stream Acquisition Milligan III Acquisition	Aug. 08, 2012 Gold Stream Acquisition Milligan III Acquisition	Aug. 31, 2012 Gold Stream Acquisition Milligan I and II Acquisition
Subsequent Event
Additional percentage of payable ounces of gold purchased					40.00%		52.25%		12.25%
Total purchase amount					$ 581,500,000				$ 200,000,000
Cash paid for acquisition of royalty interests	276,683,000	280,009,000	232,996,000			781,500,000		75,000,000		581,500,000
Cash payment for each payable ounce of gold (in dollars per ounce)							435
Future scheduled payments				$ 126,900,000	$ 216,900,000		$ 251,900,000