Derivative Financial Instruments - Summary of Derivative Cash Flow Hedges (Details) - Designated as Hedging Instrument $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) oz $ / oz Rate
Gold Put Options - 2020
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,600
Notional ounces | oz	158,700
Gold Call Options - 2020
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,875
Notional ounces | oz	158,700
Gold Put Options - 2021
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	1,626
Notional ounces | oz	126,000
Gold Call Options - 2021
Derivative [Line Items]
Average gold strike price per ounce | $ / oz	2,030
Notional ounces | oz	126,000
Mexican peso forward exchange contracts 2020
Derivative [Line Items]
Derivative, forward exchange rate | Rate	2499.00%
Derivative, notional amount | $	$ 60
Mexican peso forward exchange contracts 2021
Derivative [Line Items]
Derivative, forward exchange rate | Rate	0.00%
Derivative, notional amount | $	$ 0