Note 3. Properties, Plants, Equipment and Mineral Interests, and Lease Commitments (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Total Capital Expenditures Excluding Capital Leases	$ 130.1
Capital Leased Assets, Gross	15.8	8.9
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	5.7	3.1
Operating Leases, Rent Expense	3.0	3.0	2.4
San Jan Silver Project [Member]
Total Capital Expenditures Excluding Capital Leases	33.8
Lucky Friday [Member]
Total Capital Expenditures Excluding Capital Leases	58.1
Greens Creek [Member]
Total Capital Expenditures Excluding Capital Leases	$ 36.8