Embedded Derivatives (Details)	3 Months Ended
	Mar. 31, 2020 $ / oz $ / t oz t
Gold
Embedded Derivative [Line Items]
Under contract | oz	3,584
Average forward price | $ / oz	1,569
Silver
Embedded Derivative [Line Items]
Under contract | oz	219,721
Average forward price | $ / oz	15.77
Copper
Embedded Derivative [Line Items]
Under contract | t	436
Average forward price | $ / t	5,484
Lead
Embedded Derivative [Line Items]
Under contract | t	989
Average forward price | $ / t	1,699
Zinc
Embedded Derivative [Line Items]
Under contract | t	1,169
Average forward price | $ / t	1,878