Other, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income and Expenses [Abstract]
Foreign exchange gain (loss)	$ (9,069)	$ 1,281	$ (11,456)
Gain (loss) on sale of assets and investments	19	(1,037)	11,334
Write-Down of Manquiri Consideration	(18,599)	0	0
Write-Down of RMC Receivable	(6,536)	0	0
Gain on sale of the Joaquin project	0	21,138	0
Gain on repurchase of the Rochester royalty obligation	0	2,332	0
Mexico Inflation Adjustment	1,939	0	0
Interest Income, Other	1,776	0	0
Gain (loss) on the sale of the Endeavor stream and other royalties	0	1,036	0
Other than Temporary Impairment Losses, Investments	0	(426)	(703)
Other	5,765	2,319	923
Other, net	$ (24,705)	$ 26,643	$ 98