ROYALTY ACQUISITIONS (Details) (USD $)	9 Months Ended					1 Months Ended	9 Months Ended	1 Months Ended			1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Mt. Milligan	Dec. 19, 2011 Mt. Milligan	Dec. 14, 2011 Mt. Milligan	Oct. 31, 2010 Milligan I Acquisition oz	Mar. 31, 2012 Milligan I Acquisition	Mar. 31, 2012 Milligan II Acquisition	Dec. 31, 2011 Milligan II Acquisition subsidiary	Dec. 14, 2011 Milligan II Acquisition	Dec. 31, 2011 Milligan II Acquisition Thompson Creek subsidiary	Dec. 31, 2011 Tulsequah	Mar. 31, 2012 Tulsequah	Dec. 22, 2011 Tulsequah oz
Acquisition of Royalty Interest in Mineral Properties
Number of subsidiaries entering into the agreement									1		1	1
Total purchase price of royalty interests					$ 581,500,000	$ 311,500,000				$ 270,000,000				$ 60,000,000
Cash paid for acquisition of royalty interests	193,662,000	279,500,000				226,500,000	252,600,000	45,000,000	112,000,000			10,000,000
Maximum cash payment for each payable ounce of gold until specified threshold ounces have been delivered (in dollars per ounce)						400								450
Maximum quantity of gold with specified purchase price (in ounces)						550,000								48,000
Maximum cash payment for each payable ounce of gold over specified threshold ounces have been delivered (in dollars per ounce)						450								500
Percentage of payable ounces of gold purchased					40.00%	25.00%				15.00%
Cash payment for each payable ounce of gold (in dollars per ounce)										435
Future scheduled payments			171,900,000	216,900,000
Future scheduled payments for each quarter in calendar year 2012			45,000,000
Aggregate future scheduled payments for calendar year 2012			180,000,000
Future scheduled payments for first two quarters in calendar year 2013			12,000,000
Future scheduled payments for third quarter in calendar year 2013			12,900,000
Aggregate future scheduled payments for calendar year 2013			36,900,000
Maximum future additional payments upon satisfaction of certain conditions in the Tulsequah Agreement													50,000,000
Percentage of produced payable gold to be purchased until 48,000 ounces have been delivered														12.50%
Percentage of produced payable gold to be purchased after 48,000 ounces have been delivered														7.50%
Percentage of produced payable silver to be purchased until 2,775,000 ounces have been delivered														22.50%
Maximum cash payment for each payable ounce of silver until 2,775,000 ounces have been delivered (in dollars per ounce)														5.00
Maximum quantity of silver with maximum cash payment of $5.00 per ounce (in ounces)														2,775,000
Percentage of produced payable silver to be purchased after 2,775,000 ounces have been delivered														9.75%
Maximum cash payment for each payable ounce of silver after 2,775,000 ounces have been delivered (in dollars per ounce)														$ 7.50
Streaming percentage for payable gold and payable silver upon suspension of obligations														6.50%