QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)
Royalty revenues	$ 60,109	$ 69,638	$ 68,842	$ 64,465	$ 59,269	$ 55,546	$ 56,316	$ 45,338	$ 263,054	$ 216,469	$ 136,565
Operating income (loss)	37,107	42,893	39,420	37,468	34,634	31,877	31,604	20,810	156,888	118,925	41,035
Net income (loss) available to Royal Gold Stockholders	$ 20,571	$ 25,999	$ 23,411	$ 22,495	$ 21,687	$ 19,565	$ 18,312	$ 11,831	$ 92,476	$ 71,395	$ 21,492
Basic earnings per share (in dollars per share)	$ 0.35	$ 0.44	$ 0.42	$ 0.41	$ 0.39	$ 0.36	$ 0.33	$ 0.22	$ 1.61	$ 1.29	$ 0.49
Diluted earnings per share (in dollars per share)	$ 0.34	$ 0.44	$ 0.42	$ 0.40	$ 0.39	$ 0.35	$ 0.33	$ 0.21	$ 1.61	$ 1.29	$ 0.49