EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
EARNINGS PER SHARE ("EPS")
Net income attributable to Royal Gold common stockholders	$ 138,339	$ 166,828	$ 302,532	$ 199,343	$ 93,825
Weighted-average shares for basic EPS	65,560,468	65,542,326	65,546,400	65,523,024	65,394,627
Effect of other dilutive securities	64,099		81,191	120,366	110,908
Weighted-average shares for diluted EPS	65,624,567	65,625,965	65,627,591	65,643,390	65,505,535
Basic EPS	$ 2.11	$ 2.55	$ 4.61	$ 3.04	$ 1.43
Diluted EPS	$ 2.10	$ 2.54	$ 4.60	$ 3.03	$ 1.43