EARNINGS PER SHARE (EPS) (Details) (USD $) In Thousands, except Share data	3 Months Ended								12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
EARNINGS PER SHARE ("EPS")
Net income available to Royal Gold common stockholders	$ 21,687	$ 19,565	$ 18,312	$ 11,831	$ 10,505	$ (5,754)	$ 9,615	$ 7,126	$ 71,395	$ 21,492	$ 38,348
Weighted-average shares for basic EPS (in shares)									55,053,204	43,640,414	35,337,133
Effect of other dilutive securities (in shares)									270,206	340,403	451,943
Weighted-average shares for diluted EPS (in shares)									55,323,410	43,980,817	35,789,076
Basic earnings per share (in dollars per share)	$ 0.39	$ 0.36	$ 0.33	$ 0.22	$ 0.21	$ (0.13)	$ 0.24	$ 0.18	$ 1.29	$ 0.49	$ 1.09
Diluted earnings per share (in dollars per share)	$ 0.39	$ 0.35	$ 0.33	$ 0.21	$ 0.21	$ (0.13)	$ 0.23	$ 0.17	$ 1.29	$ 0.49	$ 1.07
Exchange basis for conversion of exchangeable shares of RG Exchangeco into shares of Royal Gold common stock									one-for-one basis