Derivative Financial Instruments (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) oz $ / oz	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 USD ($) oz $ / oz
Derivative [Line Items]
Gain (loss) on derivative instruments	$ (11,581,000)	$ 5,202,000	$ 3,618,000
Derivative instruments Settlement
Price per ounce under agreement	416
Silver concentrate sales agreements [Member] | 2016 [Member]
Derivative instruments Settlement
Derivative, notional amount	$ 5,801,000
Derivative average price | $ / oz	16.35
Outstanding Provisionally Priced Sales Consists of Silver | oz	354,771
Silver concentrate sales agreements [Member] | Thereafter [Member]
Derivative instruments Settlement
Derivative, notional amount				$ 0
Derivative average price | $ / oz				0
Notional ounces | oz				0
Gold concentrates sales agreements [Member] | 2016 [Member]
Derivative instruments Settlement
Derivative, notional amount	$ 30,810,000
Derivative average price | $ / oz	1,208
Outstanding Provisionally Priced Sales Consists of Gold | oz	25,505
Gold concentrates sales agreements [Member] | Thereafter [Member]
Derivative instruments Settlement
Derivative, notional amount				$ 0
Derivative average price | $ / oz				0
Notional ounces | oz				0