Other, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Income and Expenses [Abstract]
Foreign exchange gain (loss)	$ (670)	$ 1,206
Loss on sale of assets and investments	(574)	(2,066)
Gain on sale of the Joaquin project	0	21,138
Other	1,424	521
Other, net	$ 180	$ 20,799