Note 1. Summary of Significant Accounting Policies (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended			13 Months Ended
	Sep. 30, 2009	Sep. 30, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Oct. 31, 2010
Capitalized Drilling Costs			$ 3,600,000	$ 3,600,000	$ 1,600,000
Property, Plant and Equipment, Useful Life, Minimum				1
Property, Plant and Equipment, Useful Life, Maximum				22
Percent Of Mine License Tax			98.00%
Accrued Reclamation And Closure Costs Total			153,811,000	318,797,000	131,201,000
Foreign Currency Transaction Loss, before Tax			200,000	37,000
Foreign Currency Transaction Gain, before Tax					100,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	800,000
Derivative, Loss on Derivative		38,000	(37,988,000)	20,758,000
Payments for Hedge, Investing Activities						700,000
Share-based Compensation (in Dollars)			2,073,000	3,446,000	2,746,000
Unfunded Supplemental Executive Retirement Plan [Member]
Pension Contributions			300,000	300,000
Mine License Taxes [Member]
Taxes, Other			6,400,000	9,600,000	5,300,000
Silver [Member]
Metals Contained In Concentrates				1,200,000
Gold [Member]
Metals Contained In Concentrates				5,008
Zinc [Member]
Metals Contained In Concentrates				11,293
Lead [Member]
Metals Contained In Concentrates				3,493
Hecla Pension Plan [Member]
Pension Contributions			$ 1,100,000