Income and Mining Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Tax Examination [Line Items]
Total	$ 47,486	$ 1,635	$ 62,332	$ (14,204)
Tax (expense) benefit	15,340	2,844	28,126	(1,095)
United States
Income Tax Examination [Line Items]
United States, Income (loss) before tax	29,647	12,546	21,116	1,540
Tax (expense) benefit	(7,228)	827	(8,853)	91
Canada
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	(12,979)	(15,621)	(25,763)	(41,650)
Tax (expense) benefit	0	217	0	232
Mexico
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	30,827	4,805	63,741	26,163
Tax (expense) benefit	(8,112)	(3,888)	(19,273)	743
Other jurisdictions
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	(9)	(95)	3,238	(257)
Tax (expense) benefit	$ 0	$ 0	$ 0	$ 29