EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
EARNINGS PER SHARE ("EPS")
Net income (loss) available to Royal Gold common stockholders	$ 23,661	$ (67,656)	$ 81,509	$ (97,589)
Weighted-average shares for basic EPS	65,169,883	65,085,225	65,145,183	65,069,056
Effect of other dilutive securities (in shares)	105,043		122,018
Weighted-average shares for diluted EPS	65,274,926	65,085,225	65,267,201	65,069,056
Basic earnings (loss) per share (in dollars per share)	$ 0.36	$ (1.04)	$ 1.25	$ (1.50)
Diluted earnings (loss) per share (in dollars per share)	0.36	$ (1.04)	1.25	$ (1.50)
2019 Conversion Notes, Initial conversion price per share of common stock (in dollars per share)	$ 103.14		$ 103.14