Note 9 - Shareholders' Equity (Details)	1 Months Ended						12 Months Ended			60 Months Ended				12 Months Ended		12 Months Ended				1 Months Ended	12 Months Ended
	Jun. 30, 2017	Aug. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2013 USD ($)	Feb. 25, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Jun. 02, 2013 USD ($)	Jun. 02, 2013 CAD	Dec. 31, 2014 Series B Preferred Stock [Member] USD ($)	Dec. 31, 2013 Series B Preferred Stock [Member] USD ($)	Dec. 31, 2014 Stock Compensation Plan [Member] USD ($)	Dec. 31, 2013 Stock Compensation Plan [Member] USD ($)	Dec. 31, 2012 Stock Compensation Plan [Member] USD ($)	Dec. 31, 2014 Satisfy Withholding Obligations [Member] USD ($)	Feb. 25, 2013 Minimum [Member] USD ($)	Dec. 31, 2014 Minimum [Member] USD ($)	Dec. 31, 2014 Expense Recognized Over Remaining Vesting Period [Member] USD ($)	Dec. 31, 2014 Non-employee Directors [Member] Two Thousand Ten Stock Incentive Plan [Member]	Dec. 31, 2013 Non-employee Directors [Member] Two Thousand Ten Stock Incentive Plan [Member]	Dec. 31, 2012 Non-employee Directors [Member] Two Thousand Ten Stock Incentive Plan [Member]	Dec. 31, 2014 Two Thousand Ten Stock Incentive Plan [Member] USD ($)	Dec. 31, 2013 Two Thousand Ten Stock Incentive Plan [Member] USD ($)	Dec. 31, 2012 Two Thousand Ten Stock Incentive Plan [Member] USD ($)	Dec. 31, 2014 Directors Stock Plan [Member] USD ($)	Dec. 31, 2013 Directors Stock Plan [Member] USD ($)	Dec. 31, 2012 Directors Stock Plan [Member] USD ($)	Dec. 31, 2014 Common Stock Repurchase Program [Member] USD ($)	May 08, 2012 Common Stock Repurchase Program [Member] USD ($)
Note 9 - Shareholders' Equity (Details) [Line Items]
Common Stock, Shares Authorized							500,000,000	500,000,000		500,000,000
Common Stock, Par or Stated Value Per Share (in Dollars per share)							$ 0.25	$ 0.25		$ 0.25
Common Stock, Shares, Issued							369,528,345			369,528,345
Common Stock, Voting Rights							one
Common Stock, Dividends, Per Share, Declared (in Dollars per share)						$ 0.01														$ 0.0025	$ 0.01
Average Realized Silver Price (in Dollars)																					$ 30
Dividends, Common Stock (in Dollars)					3,600,000		(3,546,000)	(6,062,000)	(17,121,000)
Stock Repurchase Program, Authorized Amount (in Dollars)																																	20,000,000
Cumulative Stock Repurchased																																934,100
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)																			$ 3.27													$ 3.99
Stock Repurchase Program, Remaining Authorized Repurchase Amount (in Dollars)																																19,100,000
Class of Warrant or Right, Outstanding								22,307,623
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share)							$ 54,400,000			$ 54,400,000
Preferred Stock, Shares Authorized							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
Preferred Stock, Shares Outstanding							157,816	157,816		157,816				157,816
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in Dollars per share)														$ 3.50
Preferred Stock, Redemption Price Per Share (in Dollars per share)														$ 50
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)														$ 50
Preferred Stock, Liquidation Preference, Value (in Dollars)							7,891,000	7,891,000		7,891,000				7,900,000	7,900,000
Preferred Stock, Voting Rights														one
Preferred Stock Conversion Price (in Dollars per share)														$ 15.55
Preferred Stock Conversion Rate														3.2154%
Allocated Share-based Compensation Expense (in Dollars)							4,100,000									5,000,000	4,500,000	3,100,000				3,300,000				366,000	276,000	275,000	109,000	111,000	80,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars)											2,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																										20,000,000			1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant							555,167			555,167																15,414,727
Share-based Compensation Arrangement by Share-based Payment Award Method of Measuring Cost of Award Participant Numerator (in Dollars)																													24,000
Stock Issued During Period, Shares, Share-based Compensation, Gross																							110,910	94,200	59,484				39,468	28,050	18,492
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross										0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value (in Dollars)							0			0
Share Price (in Dollars per share)							$ 2.79			$ 2.79		$ 3.83	3.97
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term							1 year
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period							0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number							2,235,575	2,085,301		2,235,575
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	419,597	26,000	777,878	1,012,100			(1,234,962)
Stock Repurchased During Period, Shares																			695,961
Stock Repurchased During Period, Value (in Dollars)							$ (1,501,000)	$ (286,000)											$ 2,300,000