ACQUISITION OF INTERNATIONAL ROYALTY CORPORATION (Details) (USD $)	12 Months Ended			12 Months Ended		4 Months Ended	12 Months Ended					1 Months Ended		1 Months Ended
	Jun. 30, 2012	Jun. 30, 2010	Jun. 30, 2012 Labrador Nickel Royalty Limited Partnership (LNRLP)	Jun. 30, 2012 Altius	Jun. 30, 2012 Exchangeable Shares	Jun. 30, 2010 International Royalty Corporation	Jun. 30, 2012 International Royalty Corporation	Jun. 30, 2010 International Royalty Corporation	Feb. 22, 2010 International Royalty Corporation	Jun. 30, 2010 International Royalty Corporation Purchase price adjustments	Jun. 30, 2010 International Royalty Corporation Final purchase price allocation	Feb. 28, 2010 International Royalty Corporation Common Shares	Feb. 22, 2010 International Royalty Corporation Common Shares	Feb. 28, 2010 International Royalty Corporation Exchangeable Shares	Feb. 22, 2010 International Royalty Corporation Exchangeable Shares
Purchase price for the International Royalty Corporation (the ''IRC Transaction'')
Cash paid									$ 350,000,000
Number of common or exchangeable shares issued (in shares)												5,234,086		1,806,649
Value of common or exchangeable shares issued on date of acquisition													230,400,000		79,500,000
Exchange ratio for conversion of exchangeable shares of RG Exchangeco into shares of Royal Gold common stock	1				1
Fair values of the assets acquired and liabilities assumed
Purchase price						659,871,000		659,871,000			659,871,000
Current assets						83,720,000		83,720,000		1,069,000	84,789,000
Royalty interests in mineral properties						774,291,000		774,291,000		8,816,000	783,107,000
Other assets						14,304,000		14,304,000		(4,911,000)	9,393,000
Current liabilities						(10,839,000)		(10,839,000)		(974,000)	(11,813,000)
Senior secured debentures						(28,769,000)		(28,769,000)			(28,769,000)
Net deferred tax liabilities						(140,891,000)		(140,891,000)		(3,395,000)	(144,286,000)
Uncertain tax positions						(8,362,000)		(8,362,000)		(605,000)	(8,967,000)
Other liabilities						(2,878,000)		(2,878,000)			(2,878,000)
Non-controlling interest						(20,705,000)		(20,705,000)			(20,705,000)
Total allocated purchase price						659,871,000		659,871,000			659,871,000
Acquisition
Transaction costs						8,600,000		8,600,000
Severance related payments		19,404,000						10,800,000
Percentage of ownership interest held in Labrador Nickel Royalty Limited Partnership ("LNRLP")				10.00%			90.00%
Percentage of the Voisey's Bay Net Smelter Return (NSR) royalty owned (as a percent)			100.00%
Unaudited pro forma information
Royalty revenues								152,716,000
Net income (loss) available to Royal Gold common stockholders								(434,000)
Royalty revenue recorded on the Companys consolidated statements of operations and comprehensive income						9,000,000
Transaction costs and severance related payments								$ 19,400,000