Other, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Foreign exchange gain (loss)	$ 229	$ (1,466)	$ 2,578	$ (7,286)
Gain (loss) on sale of assets and investments	945	7,463	(607)	11,674
Gain on sale of the Joaquin project	0	0	21,138	0
Gain on repurchase of the Rochester royalty obligation	0	0	2,332	0
Gain (loss) on the sale of the Endeavor stream and other royalties	1,172	0	1,172	0
Impairment of equity securities	0	0	(426)	(20)
Other	818	408	2,252	1,494
Other, net	$ 3,164	$ 6,405	$ 28,439	$ 5,862