STREAM AND ROYALTY INTERESTS, NET - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Dec. 30, 2015
Cost	$ 3,636,306	$ 3,624,495
Accumulated Depletion	(895,825)	(732,239)
Impairments	(239,364)
Net	2,501,117	2,892,256
Wassa and Prestea
Cost			$ 145,000
Production stage stream interests
Cost	2,111,423	1,935,696
Accumulated Depletion	(373,257)	(243,595)
Net	1,738,166	1,692,101
Production stage stream interests | Mount Milligan
Cost	790,635	790,635
Accumulated Depletion	(152,833)	(114,327)
Net	637,802	676,308
Production stage stream interests | Pueblo Viejo
Cost	610,404	610,404
Accumulated Depletion	(114,944)	(67,149)
Net	495,460	543,255
Production stage stream interests | Andacollo
Cost	388,182	388,182
Accumulated Depletion	(59,851)	(39,404)
Net	328,331	348,778
Production stage stream interests | Wassa and Prestea
Cost	146,475	146,475
Accumulated Depletion	(41,601)	(22,715)
Net	104,874	123,760
Production stage stream interests | Rainy River
Cost	175,727
Accumulated Depletion	(4,028)
Net	171,699
Production stage royalty interests
Cost	844,181	844,024
Accumulated Depletion	(522,568)	(488,644)
Net	321,613	355,380
Production stage royalty interests | Voisey's Bay
Cost	205,724	205,724
Accumulated Depletion	(86,933)	(85,671)
Net	118,791	120,053
Production stage royalty interests | Penasquito
Cost	99,172	99,172
Accumulated Depletion	(38,426)	(34,713)
Net	60,746	64,459
Production stage royalty interests | Holt
Cost	34,612	34,612
Accumulated Depletion	(21,173)	(19,669)
Net	13,439	14,943
Production stage royalty interests | Cortez
Cost	20,878	20,873
Accumulated Depletion	(11,241)	(10,633)
Net	9,637	10,240
Production stage royalty interests | Other
Cost	483,795	483,643
Accumulated Depletion	(364,795)	(337,958)
Net	119,000	145,685
Total production stage stream and royalty interests
Cost	2,955,604	2,779,720
Accumulated Depletion	(895,825)	(732,239)
Net	2,059,779	2,047,481
Development stage stream interests
Cost		187,758
Net		187,758
Development stage stream interests | Rainy River
Cost		175,727
Net		175,727
Development stage stream interests | Other
Cost	12,038	12,031
Net	12,038	12,031
Development stage royalty interests
Cost	134,413	504,271
Impairments	(284)
Net	134,129	504,271
Development stage royalty interests | Pascua-Lama
Cost		380,657
Net		380,657
Development stage royalty interests | Cortez
Cost	59,803	59,803
Net	59,803	59,803
Development stage royalty interests | Other
Cost	74,610	63,811
Impairments	(284)
Net	74,326	63,811
Total development stage stream and royalty interests
Cost	146,451	692,029
Impairments	(284)
Net	146,167	692,029
Exploration stage royalty interests
Cost	534,251	152,746
Impairments	(239,080)
Net	295,171	$ 152,746
Exploration stage royalty interests | Pascua-Lama
Cost	416,770
Impairments	(239,080)
Net	177,690
Exploration stage royalty interests | Other
Cost	117,481
Net	$ 117,481