Note 9 - Shareholders' Equity (Detail) (USD $)	1 Months Ended					3 Months Ended			8 Months Ended	12 Months Ended					12 Months Ended									1 Months Ended		0 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended		12 Months Ended	3 Months Ended	12 Months Ended						12 Months Ended
	Feb. 28, 2011	Jun. 30, 2009	Feb. 28, 2009	Dec. 31, 2008	Sep. 29, 2008	Dec. 31, 2012	Jun. 30, 2012	Sep. 30, 2008	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 22, 2013	Jun. 30, 2010	Dec. 31, 2012 Non-Employee Directors Stock Plan [Member]	Dec. 31, 2011 Non-Employee Directors Stock Plan [Member]	Dec. 31, 2010 Non-Employee Directors Stock Plan [Member]	Dec. 31, 2012 Stock Award Plans [Member]	Dec. 31, 2011 Stock Award Plans [Member]	Dec. 31, 2010 Stock Award Plans [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2011 Stock Units [Member]	Dec. 31, 2008 Series 2 [Member]	Feb. 28, 2009 Series 3 [Member]	May 08, 2012 Common Stock [Member]	Dec. 31, 2012 Series B Preferred Stock [Member]	Jan. 31, 2011 Mandatory Convertible Preferred Stock [Member]	Sep. 30, 2008 Mandatory Convertible Preferred Stock [Member]	Dec. 31, 2011 Mandatory Convertible Preferred Stock [Member]	Jan. 02, 2011 Mandatory Convertible Preferred Stock [Member]	Dec. 31, 2012 Stock Units [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2011 Warrants Exercised [Member]	Dec. 31, 2012 Units Vesting in June 2012 [Member]	Dec. 31, 2012 Units Vesting in March 2014 [Member]	Dec. 31, 2012 Units Vesting In June 2015 [Member]	Dec. 31, 2012 2010 Stock Incentive Plan [Member]	Dec. 31, 2012 Directors Stock Plan [Member]	Dec. 31, 2012 2010 Stock Incentive Plan [Member]	Dec. 31, 2012 Compensation Expense Over Remaining Vesting Period [Member]
Common Stock, Shares Authorized (in Shares)						500,000,000			500,000,000	500,000,000	400,000,000
Common Stock, Par or Stated Value Per Share (in Dollars per share)						$ 0.25			$ 0.25	$ 0.25	$ 0.25
Common Stock Issued (in Shares)						285,998,136			285,998,136	285,998,136
Average Realized Silver Price						$ 29.20	$ 27.05																										$ 30
Common Stock, Dividends, Per Share, Declared (in Dollars per share)	$ 0.01
Dividends, Common Stock	3,600,000									(17,121,000)	(5,592,000)
Stock Repurchase Program, Authorized Amount																										20,000,000
Stock Repurchased During Period, Shares (in Shares)									350,300	45,341
Accelerated Share Repurchases, Final Price Paid Per Share (in Dollars per share)									$ 5.54
Stock Repurchase Program, Remaining Authorized Repurchase Amount									19,650,000
Sale of Stock, Price Per Share (in Dollars per share)													$ 4.90
Stock Issued During Period, Shares, New Issues (in Shares)				10,200,000																														2,100,000
Warrants Issued To Purchase Common Stock (in Shares)				8,100,000																				7,700,000	18,400,000
Common Stock And Warrants Issued (in Shares)			36,800,000
Stock Issued During Period, Value, New Issues																																		5,300,000
Proceeds from Warrant Exercises										700,000	5,786,000	53,093,000																						9,800,000
Preferred Stock, Shares Authorized (in Shares)						5,000,000			5,000,000	5,000,000	5,000,000
Preferred Stock, Par or Stated Value Per Share (in Dollars per share)						$ 0.25			$ 0.25	$ 0.25	$ 0.25
Preferred Stock, Shares Outstanding (in Shares)						157,816			157,816	157,816	157,816																157,816
Conversion of Stock, Shares Converted (in Shares)																												2,012,500
Stock Issued During Period, Shares, Conversion of Convertible Securities (in Shares)																														18,900,000
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in Dollars per share)												$ 3.50
Preferred Stock, Dividends, Per Share, Cash Paid (in Dollars per share)								$ 0.875
Preferred Stock, Dividend Rate, Percentage																													6.50%
Temporary Equity, Liquidation Preference Per Share (in Dollars per share)												$ 100
Preferred Stock, Dividends Per Share, Declared (in Dollars per share)					$ 1.625
Dividends, Preferred Stock, Stock		3,270,000										22,891,000
Preferred Stock, Redemption Price Per Share (in Dollars per share)						$ 50			$ 50	$ 50
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)						$ 50			$ 50	$ 50
Liquidation Preference Preferred Stock		7.9				7,891,000			7,891,000	7,891,000	7,891,000
Preferred Stock Conversion Price (in Dollars per share)																											$ 15.55
Preferred Stock Conversion Rate (in Shares)																											3.2154				9.3773
Conversion Of Convertible Preferred Stock To Common Stock																												18,900,000
Share-based Compensation										3,101,000	2,073,000	3,446,000						3,100,000	2,100,000	3,400,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized																		2,000,000																							3,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)														20,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in Shares)																																						19,605,740	622,685
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period (in Shares)																	48,825
Allocated Share-based Compensation Expense										200,000	147,000	263,000			80,000	194,000	168,000						500,000																	275,000
Stock Issued During Period, Shares, Share-based Compensation, Gross (in Shares)																	33,068
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)												352,517
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value						900,000			900,000	900,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value																					600,000	1,500,000
Proceeds from Stock Options Exercised											500,000	3,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number (in Shares)						1,037,146			1,037,146	1,037,146	561,276																								202,662	180,732	145,952
Employee Benefits and Share-based Compensation										2,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in Shares)										231,338	314,826																					54,870
Stock Repurchased During Period, Value										$ (1,941,000)																						$ 200,000
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)										$ 4.47