Note 4. Commitments, Contingencies and Obligations (Detail) (USD $)	1 Months Ended				6 Months Ended				6 Months Ended					3 Months Ended	6 Months Ended
	Feb. 29, 2012	Jun. 30, 2011	Jan. 31, 2010	Apr. 30, 2009	Jun. 30, 2012	Jun. 30, 2011	Oct. 31, 2011	Sep. 08, 2011	Jun. 30, 2012 Barker-Hughesville Site [Member]	Jun. 30, 2012 Black Pine Mine Site [Member]	Jun. 30, 2012 Van Stone Mine Site [Member]	Jun. 30, 2012 Greens Creek [Member]	Jun. 30, 2012 Lucky Friday [Member]	Mar. 31, 2012 Johnny M Mine [Member]	Jun. 30, 2012 Greens Creek [Member]
Maximum Environmental Remediation Obligation					$ 2,500,000
AdministrativePenalty				177,500
IncurredResponseCosts			91,000,000
EstimatedFutureResponseCost		100,000,000	72,000,000
ContributionAndCostRecovery									9,000,000	17,700,000	3,500,000
Payments to Acquire Land	1,875,000
Other Accrued Liabilities, Noncurrent					1,400,000
Increase (Decrease) in Other Accrued Liabilities					(3,602,000)	(1,178,000)								500,000
EstimatedResponseCosts		4,500,000
Contractual Obligations					7,900,000
Open Purchase Orders												11,200,000	800,000
Noncapital Costs					26,000,000										400,000
Commitments for Capital Lease Payments					14,400,000
Environmental Litigation and Related Claims								95,400,000
Annual Maintenance Fee							600,000
Letters of Credit Outstanding, Amount					600,000
United Steel Workers Claims Lower Range					0
UnitedSteelWorkersClaimsUpperRange					$ 10,000,000