Income and Mining Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Examination [Line Items]
Income (loss) before income and mining taxes	$ (48,368)	$ 39,969	$ 13,964	$ 25,765
Tax (expense) benefit	6,400	13,113	34,526	12,018
United States
Income Tax Examination [Line Items]
United States, Income (loss) before tax	(30,247)	24,592	(9,131)	26,132
Tax (expense) benefit	4,078	(6,003)	(4,775)	(5,913)
Canada
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	(13,879)	(12,895)	(39,643)	(54,544)
Tax (expense) benefit	0	0	0	232
Mexico
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	(4,138)	28,320	59,603	54,483
Tax (expense) benefit	(10,478)	(7,110)	(29,751)	(6,366)
Other jurisdictions
Income Tax Examination [Line Items]
Foreign, Income (loss) before tax	(104)	(48)	3,135	(306)
Tax (expense) benefit	$ 0	$ 0	$ 0	$ 29