Derivative Financial Instruments - Summary of Mark-to-Market Gain (Losses) on Derivative Instruments (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) $ / oz	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net, pretax	$ 3,638,000	$ (864,000)	$ (11,581,000)
Fair value adjustments, net	$ 804,000	631,000	(7,687,000)
Zinc put options purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Weighted Average Strike Price of Put Options | $ / oz	3,000.00
Provisional metal sales contracts
Derivative Instruments, Gain (Loss) [Line Items]
Provisional gain (loss) on derivatives and commodity contracts	$ 111,000	631,000		$ (239,000)
Palmarejo gold production royalty
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net, pretax	0	0	(5,866,000)
Zinc options
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain (loss)	753,000	0	0
Silver and Gold Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value adjustments, net, pretax	$ 0	0	(1,582,000)
Zinc call options sold
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Weighted Average Strike Price of Call Options	4,050
Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain (loss)	$ (60,000)	$ 0	$ 0