EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Net income (loss) available to Royal Gold common stockholders	$ 20,020	$ 23,661	$ 28,062	$ 29,787	$ 20,439	$ (67,656)	$ 15,114	$ (45,046)	$ 101,530	$ (77,149)	$ 51,965
Weighted-average shares for basic EPS									65,152,782	65,074,455	65,007,861
Effect of other dilutive securities (in shares)									125,171		117,312
Weighted-average shares for diluted EPS									65,277,953	65,074,455	65,125,173
Basic earnings (loss) per share (in dollars per share)	$ 0.31	$ 0.36	$ 0.43	$ 0.46	$ 0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 1.55	$ (1.18)	$ 0.80
Diluted earnings (loss) per share (in dollars per share)	0.31	$ 0.36	$ 0.43	$ 0.46	$ 0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 1.55	$ (1.18)	$ 0.80
2019 Notes
Dilutive effect of conversion of debt securities									0
Initial conversion price (in dollars per share)	$ 105.31								$ 105.31