Derivative Financial Instruments - Summary of Provisionally Priced Sales (Details) $ in Thousands	Mar. 31, 2020 USD ($) oz $ / oz
Silver concentrate sales agreements | 2018
Derivative instruments Settlement
Derivative average price | $ / oz	14.86
Outstanding Provisionally Priced Sales Consists of Silver | oz	302,871
Notional Amount Derivative | $	$ 4,500
Silver concentrate sales agreements | Thereafter
Derivative instruments Settlement
Derivative average price | $ / oz	0
Outstanding Provisionally Priced Sales Consists of Silver | oz	0
Notional Amount Derivative | $	$ 0
Gold concentrates sales agreements | 2018
Derivative instruments Settlement
Derivative average price | $ / oz	1,596
Notional Amount Derivative | $	$ 8,346
Outstanding Provisionally Priced Sales Consists of Gold | oz	5,230
Gold concentrates sales agreements | Thereafter
Derivative instruments Settlement
Derivative average price | $ / oz	0
Notional Amount Derivative | $	$ 0
Outstanding Provisionally Priced Sales Consists of Gold | oz	0
Zinc concentrates sales agreements [Member] | 2018
Derivative instruments Settlement
Derivative average price | $ / oz	0.86
Notional Amount Derivative | $	$ 11,769
Outstanding Provisionally Priced Sales Consists of Gold | oz	13,615,188
Zinc concentrates sales agreements [Member] | Thereafter
Derivative instruments Settlement
Derivative average price | $ / oz	0
Notional Amount Derivative | $	$ 0
Outstanding Provisionally Priced Sales Consists of Gold | oz	0
Lead concentrates sales agreements [Member] | 2018
Derivative instruments Settlement
Derivative average price | $ / oz	0.79
Notional Amount Derivative | $	$ 3,028
Outstanding Provisionally Priced Sales Consists of Gold | oz	3,830,017
Lead concentrates sales agreements [Member] | Thereafter
Derivative instruments Settlement
Derivative average price | $ / oz	0
Notional Amount Derivative | $	$ 0
Outstanding Provisionally Priced Sales Consists of Gold | oz	0