Note 11 - Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]

September 30, 2014	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(pounds)
Contracts on provisional sales
2014 settlements		901		3		27,668		6,449	$	17.35	$	1,224	$	1.03	$	0.94
Contracts on forecasted sales
2014 settlements		—		—		717		—		N/A		N/A	$	1.03		N/A
2015 settlements		—		—		61,950		29,652		N/A		N/A	$	0.98	$	1.07
2016 settlements		—		—		44,699		34,337		N/A		N/A	$	0.99	$	1.03
2017 settlements		—		—		1,984		—		N/A		N/A	$	1.04		N/A

December 31, 2013	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(pounds)
Contracts on provisional sales
2014 settlements		673		3		11,188		3,472	$	19.50	$	1,205	$	0.89	$	1.00
Contracts on forecasted sales
2014 settlements		—		—		31,967		34,282		N/A		N/A	$	1.00	$	1.04
2015 settlements		—		—		39,683		36,982		N/A		N/A	$	0.96	$	1.07
2016 settlements		—		—		3,803		30,589		N/A		N/A	$	0.93	$	1.03