EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
EARNINGS PER SHARE ("EPS")
Net (loss) income available to Royal Gold common stockholders	$ 20,439	$ (67,656)	$ 15,114	$ (45,046)	$ 14,819	$ 25,014	$ (6,548)	$ 18,680	$ (77,149)	$ 51,965	$ 62,641
Weighted-average shares for basic EPS									65,074,455	65,007,861	64,909,149
Effect of other dilutive securities (in shares)										117,312	117,107
Weighted-average shares for diluted EPS									65,074,455	65,125,173	65,026,256
Basic (loss) earnings per share (in dollars per share)	$ 0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 0.23	$ 0.38	$ (0.10)	$ 0.29	$ (1.18)	$ 0.80	$ 0.96
Diluted (loss) earnings per share (in dollars per share)	0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 0.23	$ 0.38	$ (0.10)	$ 0.29	(1.18)	$ 0.80	$ 0.96
Impact on diluted earnings per share (in dollars per share)									0
2019 Conversion Notes, Initial conversion price per share of common stock (in dollars per share)	$ 105.31								$ 105.31