SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)
Long Lived Assets and Pre-Tax Income by Geographical Information
Number of reportable segments | segment	2
Revenue	$ 117,947	$ 74,056
Cost of sales	22,662	11,466
Net revenue	95,285	62,590
Total stream and royalty interests, net	2,898,094		$ 2,848,087
Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,025,727		1,038,258
Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	578,861		588,502
Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	816,823		823,525
Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	115,902		118,899
United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	170,128		102,385
Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	107,088		89,293
Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	41,007		42,547
Other
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	42,558		44,678
Stream interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	85,504	37,857
Cost of sales	22,662	11,466
Net revenue	62,842	26,391
Total stream and royalty interests, net	1,859,659		1,868,715
Stream interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	38,386	23,518
Cost of sales	12,578	9,128
Net revenue	25,808	14,390
Total stream and royalty interests, net	799,075		809,692
Stream interest | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	20,950
Cost of sales	5,896
Net revenue	15,054
Total stream and royalty interests, net	578,861		588,502
Stream interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	20,169	10,715
Cost of sales	2,998	1,604
Net revenue	17,171	9,111
Total stream and royalty interests, net	363,269		369,896
Stream interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	5,999	3,624
Cost of sales	1,190	734
Net revenue	4,809	2,890
Total stream and royalty interests, net	106,422		88,596
Stream interest | Other
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	12,032		12,029
Royalty interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	32,443	36,199
Net revenue	32,443	36,199
Total stream and royalty interests, net	1,038,435		979,372
Royalty interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	6,188	10,401
Net revenue	6,188	10,401
Total stream and royalty interests, net	226,652		228,566
Royalty interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	489
Net revenue	489
Total stream and royalty interests, net	453,554		453,629
Royalty interest | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	9,596	10,805
Net revenue	9,596	10,805
Total stream and royalty interests, net	115,902		118,899
Royalty interest | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	9,706	10,213
Net revenue	9,706	10,213
Total stream and royalty interests, net	170,128		102,385
Royalty interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	824	257
Net revenue	824	257
Total stream and royalty interests, net	666		697
Royalty interest | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	3,462	2,451
Net revenue	3,462	2,451
Total stream and royalty interests, net	41,007		42,547
Royalty interest | Other
Long Lived Assets and Pre-Tax Income by Geographical Information
Revenue	2,178	2,072
Net revenue	2,178	$ 2,072
Total stream and royalty interests, net	$ 30,526		$ 32,649