Note 4. Commitments and Contingencies (Detail) (USD $)	1 Months Ended			3 Months Ended			6 Months Ended			9 Months Ended	12 Months Ended				6 Months Ended		6 Months Ended	4 Months Ended	16 Months Ended	28 Months Ended	4 Months Ended		43 Months Ended			1 Months Ended	6 Months Ended
	Jan. 31, 2010	Dec. 31, 2009	Apr. 30, 2009	Jun. 30, 2011	Jun. 30, 2010	Nov. 30, 2008	Jun. 13, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Dec. 31, 2007	Feb. 01, 2010	Sep. 30, 2002	Jun. 30, 2011 Greens Creek [Member]	Jun. 30, 2011 Greens Creek [Member]	Jun. 30, 2011 Lucky Friday [Member]	Jun. 30, 2011 Lucky Friday [Member]	May 12, 2011 Accrual For Basin Claims Cash [Member]	May 12, 2012 Accrual For Basin Claims Cash [Member]	May 12, 2013 Accrual For Basin Claims Cash [Member]	May 12, 2011 Accrua For Basin Claims Cash OrCommon Stock [Member]	May 12, 2011 Accrual For Basin Claims Proceeds From Warrants [Member]	Aug. 01, 2014 Accrual For Basin Claims Proceeds From Warrants [Member]	Aug. 01, 2014 Warrants Minimum Exercise Price [Member]	Aug. 01, 2014 Warrants Maximum Exercise Price [Member]	Jun. 13, 2011 Foregone Payments [Member]	Jun. 30, 2011 Accrualfor Basin Claims [Member]
Payments for Legal Settlements							$ 263,400,000											$ 102,000,000	$ 25,000,000	$ 15,000,000	$ 55,500,000	$ 9,500,000	$ 56,400,000			$ 197.5
Future Clean Up Costs												1,300,000,000	359,000,000
Claims For Natural Resource Damages, Lower Range												2,000,000,000
Claims For Natural Resource Damages, Upper Range												3,400,000,000
Proceeds from (Repayments of) Other Debt		482,000,000
Investment Warrants, Exercise Price (in Dollars per share)																								$ 2.45	$ 2.50
Legal Settlement Interest Rate																										3.25%
Legal Settlement Accrued Interest																										1,069,792
Superfund Rate				0.69%				0.69%		0.69%
Environmental Expense and Liabilities								556,000	2,502,000	193,200,000																	262,200,000
Proceeds from Insurance Settlement, Operating Activities											7,200,000
Past Environmental Remediation Costs						52,000
EstimatedFutureCleanUpCost						291,000
PercentOtherCost						12.50%
Maximum Environmental Remediation Obligation								2,500,000
AdministrativePenalty			177,500
IncurredResponseCosts	91,000,000
EstimatedFutureResponseCost	72,000,000
Purchase Commitment, Remaining Minimum Amount Committed				5,500,000				5,500,000		5,500,000
NonCapitalCostPurchaseOrders															1,300,000
Accounts Payable, Other														5,300,000		2,200,000
Other Cost and Expense, Operating				2,270,000	1,601,000			4,087,000	2,565,000						900,000		100,000
ApproximateCapitalLeaseObligationIncludingInterest				8,100,000				8,100,000		8,100,000
Letters of Credit Outstanding, Amount				$ 600,000				$ 600,000		$ 600,000