EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
EARNINGS PER SHARE ("EPS")
Net income (loss) available to Royal Gold common stockholders	$ 41,321	$ 23,586	$ 111,774	$ 38,596
Net income and comprehensive income available to Royal Gold common stockholders	$ 41,321	$ 23,586	$ 111,774	$ 38,596
Weighted-average shares for basic EPS	65,495,907	65,395,457	65,480,759	65,385,161
Effect of other dilutive securities (in shares)	115,660	77,943	132,647	100,262
Weighted-average shares for diluted EPS	65,611,567	65,473,400	65,613,406	65,485,423
Basic earnings per share (in dollars per share)	$ 0.63	$ 0.36	$ 1.70	$ 0.59
Diluted earnings per share (in dollars per share)	$ 0.63	$ 0.36	$ 1.70	$ 0.59