Note 8. Shareholders’ Equity (Detail) (USD $)	1 Months Ended		3 Months Ended					9 Months Ended
	Jun. 30, 2011	Jan. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Apr. 12, 2011	Dec. 31, 2010	Jun. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Stock Issued During Period, Shares, New Issues (in Shares)	7,968			42,636			48,825
Share-based Compensation	$ 100,000							$ 1,497,000	$ 3,336,000
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period (in Shares)	256,927
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in Shares)	163,649
Restricted Stock or Unit Expense	600,000
Employee Benefits and Share-based Compensation								1,500,000	3,300,000
Stock Repurchased During Period, Shares (in Shares)								56,688
Stock Repurchased During Period, Value								500,000
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)								$ 8.29
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options								500,000	400,000
Common Stock, Dividends, Per Share, Declared (in Dollars per share)			$ 0.02
Dividends, Common Stock			5,600,000
Average Realized Silver Price			37.02
Debt Instrument, Convertible, Conversion Ratio		9.3773
Stock Issued During Period, Shares, Conversion of Convertible Securities (in Shares)		18,900,000
Mandatory Convertible Preferred Stock Dividend						3,300,000
Warrants Exercised			1,900,000					1,900,000
Proceeds from Warrant Exercises					9,500,000			4,600,000
Vesting 2012 [Member]
RemainingStockUnitAwardExpense								1,400,000
Vesting 2014 [Member]
RemainingStockUnitAwardExpense								$ 1,100,000