OPERATIONS, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED AND RECENTLY ADOPTED ACCOUNTING STANDARDS (Details)	6 Months Ended
Dec. 31, 2017 item
OPERATIONS, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED AND RECENTLY ADOPTED ACCOUNTING STANDARDS
Minimum number of metals produced from a mine of which right to purchase all or a portion available in exchange for upfront deposit	1

Represents the minimum number of metals produced from a mine of which the right to purchase all or a portion is available in exchange for upfront deposit.

No definition available.

Name:	rgld_MinimumNumberOfMetalsProducedFromMineOfWhichRightToPurchaseInAllOrPortionAvailableInExchangeForUpfrontDeposit
Namespace Prefix:	rgld_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration