EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
EARNINGS PER SHARE ("EPS")
Net income attributable to Royal Gold common stockholders	$ 54,026	$ 38,554	$ 220,855	$ 150,329
Weighted-average shares for basic EPS	65,550,400	65,511,878	65,544,978	65,501,678
Effect of other dilutive securities (in shares)	71,203	88,892	79,494	124,722
Weighted-average shares for diluted EPS	65,621,603	65,600,770	65,624,472	65,626,400
Basic EPS (in dollars per share)	$ 0.82	$ 0.59	$ 3.36	$ 2.30
Diluted EPS (in dollars per share)	$ 0.82	$ 0.59	$ 3.36	$ 2.29