STREAM AND ROYALTY INTERESTS, NET - Impairments (Details) $ in Thousands			3 Months Ended		12 Months Ended
	Jan. 11, 2016 oz	Dec. 22, 2014 USD ($)	Mar. 31, 2016 USD ($) item	Sep. 30, 2014 USD ($) item	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2017 USD ($)	Dec. 20, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Impairments of stream and royalty interests					$ 96,118	$ 28,339
Impairment of stream and royalty interests and royalty receivables					98,588	31,335
Value of stream and royalty interests, net					2,848,087		$ 2,892,256
Royalty receivables					17,990		$ 23,461
Return of advance payment						10,000
Phoenix Gold
Impairments of stream and royalty interests					75,702
Value of stream and royalty interests, net			$ 0					$ 0
Inata
Impairments of stream and royalty interests					11,982
Allowance for royalty receivables					2,855
Royalty interests acquired (as a percent)							2.50%
Value of stream and royalty interests, net			0						$ 12,000
Royalty receivables							$ 2,800
Wolverine
Impairments of stream and royalty interests					5,307	25,967
Allowance for royalty receivables					(385)	2,996
Value of stream and royalty interests, net			0			5,300
Royalty receivables						3,000
Other
Impairments of stream and royalty interests			3,100	$ 1,800	3,127	$ 2,372
Value of stream and royalty interests, net			$ 0	$ 0
Tulsequah
Value of stream and royalty interests, net		$ 10,000								$ 0
Return of advance payment		10,000
Direct transaction costs		$ 600
Initial Royalty | Phoenix Gold
Royalty interests acquired (as a percent)	6.30%
Gold delivered (in ounces) | oz	135,000
Subsequent Royalty | Phoenix Gold
Royalty interests acquired (as a percent)	3.15%
Production stage royalty interests
Value of stream and royalty interests, net					378,115		355,380
Production stage royalty interests | Other
Value of stream and royalty interests, net					170,670		145,685
Number of properties | item			1	1
Exploration stage royalty interests
Value of stream and royalty interests, net					$ 154,186		$ 152,746
Exploration stage royalty interests | Other
Number of properties | item			3	1
Minimum | Wolverine
Royalty interests acquired (as a percent)							0.00%
Maximum | Wolverine
Royalty interests acquired (as a percent)							9.445%