STREAM AND ROYALTY INTERESTS, NET (Details) - USD ($) $ in Thousands	3 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Royalty Revenue	$ 99,992	$ 112,476
Royalty payments quarterly due period	45 days
Royalty interest
Royalty Revenue	$ 29,955	$ 33,714
Voisey's Bay
Net smelter return (NSR) (as a percent)	3.00%
Gross metal value (as a percent)	50.00%
Voisey's Bay \| LNRLP
Ownership percentage held	90.00%
Voisey's Bay \| LNRLP \| Altius
Ownership percentage held	10.00%
Voisey's Bay \| Royalty interest
Royalty Revenue	$ 4,900

Represents percentage of gross metal value in the concentrates at existing nickel, copper and cobalt prices

No definition available.

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- Definition

Represents percentage of net smelter return.

+ References

No definition available.

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- Definition

Represents the quarterly payment due period after the respective quarter-end under the royalty arrangements.

+ References

No definition available.

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- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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