Derivative Financial Instruments (Details Textual) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017 USD ($) oz $ / oz	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) oz $ / oz	Jun. 30, 2016 USD ($)	Jan. 21, 2009 oz
Palmarejo gold production royalty [Member]
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Production to be sold, percent						50.00%
Payment made for gold on the end of royalty obligation | oz						4,167
Concentrate Sales Contracts [Member]
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Unrealized Gain (Loss) on Derivatives and Commodity Contracts | $	$ 0.8		$ 0.6	$ 0.6	$ 1.2
Silver and gold options [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net | $			0.1		1.6
ERROR in label resolution.
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net | $		$ 0.0	0.9		5.8
Realized losses | $			$ 4.3		$ 7.3
Maximum [Member] | Palmarejo gold production royalty [Member]
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Payable ounces under royalty obligation | oz						400,000
Derivative Instruments Settle in Year One [Member] | Silver concentrate sales agreements [Member]
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Outstanding provisionally priced sales consists of silver | oz	118,361			118,361
Derivative Average Price | $ / oz	16.85			16.85
Derivative Instruments Settle in Year One [Member] | Gold concentrates sales agreements [Member]
Additional Derivative Financial Instruments and Fair Value of Financial Instruments (Textual) [Abstract]
Outstanding provisionally priced sales consists of Gold | oz	32,602			32,602
Derivative Average Price | $ / oz	1,262.67			1,262.67