ACQUISITIONS (Details)	12 Months Ended			0 Months Ended								0 Months Ended				12 Months Ended			0 Months Ended							0 Months Ended
	Jun. 30, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2013 Seabridge	Jun. 16, 2011 Seabridge Initial Shares USD ($)	Jun. 16, 2011 Seabridge Initial Shares CAD	Oct. 28, 2011 Seabridge Initial Royalty CAD item	Jun. 16, 2011 Seabridge Initial Royalty	Dec. 13, 2012 Seabridge Additional Shares USD ($)	Dec. 13, 2012 Seabridge Additional Shares CAD	Jun. 16, 2011 Seabridge Additional Shares CAD	Dec. 13, 2012 Seabridge NSR Royalty Option 1 CAD	Dec. 13, 2012 Seabridge NSR Royalty Option 2 CAD	Dec. 13, 2012 Seabridge Increased Royalty CAD item	Jun. 16, 2011 Seabridge Increased Royalty	Jun. 30, 2013 Mt. Milligan USD ($)	Aug. 08, 2012 Mt. Milligan USD ($)	Jul. 31, 2012 Mt. Milligan USD ($)	Dec. 19, 2011 Milligan II Acquisition USD ($)	Dec. 14, 2011 Milligan II Acquisition USD ($) item	Dec. 14, 2011 Milligan II Acquisition Thompson Creek item	Aug. 08, 2012 Milligan III Acquisition USD ($)	May 23, 2012 Ruby Hill Royalty Acquisition USD ($)	May 23, 2012 Ruby Hill Royalty Acquisition Production stage royalty interests USD ($)	May 23, 2012 Ruby Hill Royalty Acquisition Exploration stage royalty interests USD ($)	Dec. 28, 2011 Tulsequah USD ($)	Dec. 22, 2011 Tulsequah USD ($) item oz	Jun. 30, 2013 Tulsequah USD ($)
Acquisition of Royalty Interest in Mineral Properties
Percentage of payable ounces of gold purchased																	52.25%			15.00%		12.25%
Total purchase amount																	$ 781,500,000	$ 581,500,000		$ 270,000,000		$ 200,000,000	$ 38,000,000	$ 24,300,000	$ 13,700,000		$ 60,000,000
Agreement for acquisition of common shares											18,000,000
Cash payment for each payable ounce of gold (in dollars per ounce)																	435
Cash paid for acquisition of royalty interests	314,262,000	276,683,000	280,009,000																112,000,000			75,000,000				10,000,000
Total cash paid on pre-production commitment																768,600,000
Future scheduled payments due for third quarter in calendar year 2013																12,900,000
Common shares acquired in a private placement					1,019,000	1,019,000			1,004,491	1,004,491
Payment made for common shares acquired			28,574,000		30,700,000	30,000,000			18,300,000	18,000,000
Payment made for common shares acquired (in dollars per share)					$ 30.14	29.4
Premium on share price as a percentage of the volume weighted average trading price of common shares					15.00%	15.00%			15.00%	15.00%
Trading period used to calculate premium on share price					5 days	5 days			5 days	5 days
Percentage of royalty that can be acquired								1.25%				1.25%	2.00%		2.00%
Holding period of shares as a condition to acquire additional shares							270 days		270 days	270 days
Purchase price of royalty							100,000,000					100,000,000	160,000,000	60,000,000
Number of installments in which the purchase price of royalty is payable							3							3
Installment period in which the purchase price of royalty is payable							540 days							540 days
Proceeds from sale of shares in private transaction									14,600,000	14,400,000
Exercisable period to acquire the Initial Royalty and the Increased Royalty				60 days
Realized loss on trading securities									1,300,000
Percentage of royalty interests acquired																							3.00%
Number of subsidiaries entering into the agreement																				1	1						1
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%
Maximum cash payment for each payable ounce of gold until specified threshold ounces have been delivered (in dollars per ounce)																											450
Maximum quantity of gold with specified purchase price (in ounces)																											48,000
Percentage of produced payable gold to be purchased after 48,000 ounces have been delivered																											7.50%
Maximum cash payment for each payable ounce of gold over specified threshold ounces have been delivered (in dollars per ounce)																											500
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%
Inflation adjustment																	$ 0