QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)
Revenue	$ 108,934	$ 106,972	$ 106,961	$ 117,947	$ 94,129	$ 93,487	$ 98,118	$ 74,056	$ 440,814	$ 359,790	$ 278,019
Operating income (loss)	34,619	35,951	34,481	40,891	28,516	(72,058)	27,173	21,185	145,942	4,816	87,235
Net (loss) income attributable to Royal Gold stockholders	$ 20,020	$ 23,661	$ 28,062	$ 29,787	$ 20,439	$ (67,656)	$ 15,114	$ (45,046)	$ 101,530	$ (77,149)	$ 51,965
Basic earnings (loss) per share (in dollars per share)	$ 0.31	$ 0.36	$ 0.43	$ 0.46	$ 0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 1.55	$ (1.18)	$ 0.80
Diluted earnings (loss) per share (in dollars per share)	$ 0.31	$ 0.36	$ 0.43	$ 0.46	$ 0.32	$ (1.04)	$ 0.23	$ (0.69)	$ 1.55	$ (1.18)	$ 0.80