Derivative Financial Instruments - Summary of Derivative Cash Flow Hedges (Details) - Designated as Hedging Instrument $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($) oz $ / oz Rate
Gold Put Options - 2020
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,600
Notional ounces | oz	79,350
Gold Call Options - 2020
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,882
Notional ounces | oz	79,350
Gold Put Options - 2021
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,630
Notional ounces | oz	132,000
Gold Call Options - 2021
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	2,038
Notional ounces | oz	132,000
Mexican peso forward exchange contracts 2020
Derivative [Line Items]
Derivative, forward exchange rate | Rate	2528.00%
Derivative, notional amount | $	$ 30
Mexican peso forward exchange contracts 2021
Derivative [Line Items]
Derivative, forward exchange rate | Rate	0.00%
Derivative, notional amount | $	$ 0