EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
EARNINGS PER SHARE ("EPS")
Net income available to Royal Gold common stockholders	$ 15,008	$ 28,631
Weighted-average shares for basic EPS	65,374,866	65,235,496
Effect of other dilutive securities (in shares)	122,293	169,184
Weighted-average shares for diluted EPS	65,497,159	65,404,680
Basic earnings per share (in dollars per share)	$ 0.23	$ 0.44
Diluted earnings per share (in dollars per share)	0.23	$ 0.44
Initial conversion price (in dollars per share)	$ 102.43