Document and Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2019	Jul. 31, 2019	Dec. 31, 2018
Document and Entity Information
Document Type	10-K
Entity Registrant Name	ROYAL GOLD INC
Document Period End Date	Jun. 30, 2019
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 5,576,392,624
Entity Shares Outstanding		65,559,787
Entity Central Index Key	0000085535
Current Fiscal Year End Date	--06-30
Document Fiscal Year Focus	2019
Amendment Flag	false
Document Fiscal Period Focus	FY