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Note 8 - Shareholders' Equity (Details Textual) |  |  | 1 Months Ended | 3 Months Ended | 7 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 04, 2016 USD ($) $ / shares | Sep. 13, 2016 shares | Sep. 30, 2016 USD ($) shares | Jun. 30, 2016 $ / oz shares | Mar. 31, 2016 USD ($) shares | Sep. 30, 2016 USD ($) $ / shares shares | Jun. 30, 2016 USD ($) $ / oz | Sep. 30, 2015 $ / shares | Sep. 30, 2016 USD ($) shares | Sep. 30, 2016 USD ($) $ / shares shares | Sep. 30, 2015 USD ($) $ / shares shares | Feb. 23, 2016 USD ($) | Dec. 31, 2015 $ / shares shares | May 08, 2012 shares
RSUs Vesting in 2019 [Member] | Share-based Compensation Award, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage |  |  |  |  |  |  |  |  |  | 33.00% |  |  |  |
RSUs Vesting in 2019 [Member] | Share-based Compensation Award, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage |  |  |  |  |  |  |  |  |  | 33.00% |  |  |  |
RSUs Vesting in 2019 [Member] | Share-based Compensation Award, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage |  |  |  |  |  |  |  |  |  | 33.00% |  |  |  |
RSUs Vesting in 2019 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  | 952,612 |  |  |  |  |  |  |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ |  |  | $ 1,400,000 |  |  | $ 1,400,000 |  |  | $ 1,400,000 | $ 1,400,000 |  |  |  |
Stock Awards [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period |  |  |  |  | 2,335,196 |  |  |  |  |  |  |  |  |
Allocated Share-based Compensation Expense | $ |  |  |  |  | $ 5,500,000 |  |  |  |  |  |  |  |  |
RSUs Vesting in 2018 [Member] | Share-based Compensation Award, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |
RSUs Vesting in 2018 [Member] | Share-based Compensation Award, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |
RSUs Vesting in 2018 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  | 87,493 |  |  |  |  |  |  |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  |  |  |  | 2 years |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ |  |  | 1,600,000 |  |  | 1,600,000 |  |  | 1,600,000 | $ 1,600,000 |  |  |  |
RSUs Vesting in 2017 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  | 43,187 |  |  |  |  |  |  |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  |  |  |  | 1 year |  |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ |  |  | $ 1,800,000 |  |  | $ 1,800,000 |  |  | $ 1,800,000 | $ 1,800,000 |  |  |  |
Non-Employee Directors [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period |  |  |  |  |  |  |  |  |  | 185,353 | 48,246 |  |  |
Employees and Non-employee Directors [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allocated Share-based Compensation Expense | $ |  |  |  |  |  |  |  |  |  | $ 4,800,000 | $ 4,000,000 |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Dividends, Per Share, Declared | $ / shares |  |  |  |  |  |  |  |  |  | $ 0.01 |  |  |  |
Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Aggregate Offering Price | $ |  |  |  |  |  |  |  |  |  |  |  | $ 75,000,000 |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Dividends, Per Share, Declared | $ / shares | $ 0.0025 |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends, Common Stock | $ | $ 1,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Share Price | $ / shares | $ 6.46 |  |  |  |  |  |  |  |  |  |  |  |  |
Mines Management [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares |  | 8,309,006 | 8,309,006 |  |  |  |  |  |  |  |  |  |  |
Common Stock Repurchase Program [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Treasury Stock Acquired, Average Cost Per Share | $ / shares |  |  |  |  |  |  |  |  |  | $ 3.99 |  |  |  |
Stock Repurchase Program, Number of Shares Authorized to be Repurchased |  |  |  |  |  |  |  |  |  |  |  |  |  | 20,000,000
Cumulative Stock Repurchased |  |  | 934,100 |  |  | 934,100 |  |  | 934,100 | 934,100 |  |  |  |
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased |  |  | 19,100,000 |  |  | 19,100,000 |  |  | 19,100,000 | 19,100,000 |  |  |  |
Class of Warrant or Right, Outstanding |  |  | 0 |  |  | 0 |  |  | 0 | 0 |  |  | 2,249,550 |
Shares Paid for Tax Withholding for Share Based Compensation |  |  |  |  |  |  |  |  |  | 1,010,509 | 613,698 |  |  |
Payments Related to Tax Withholding for Share-based Compensation | $ |  |  |  |  |  |  |  |  |  | $ 3,500,000 | $ 1,900,000 |  |  |
Treasury Stock Acquired, Average Cost Per Share | $ / shares |  |  |  |  |  |  |  |  |  | $ 3.44 | $ 3.05 |  |  |
Common Stock, Dividends, Per Share, Declared | $ / shares |  |  |  |  |  | $ 0.0025 |  | $ 0.0025 |  | $ 0.0075 | $ 0.0075 |  |  |
Average Realized Silver Price | $ |  |  |  |  |  |  | $ 19.53 |  |  |  |  |  |  |
Average Realized Silver Price Minimum Dividend Threshold | $ / oz |  |  |  | 30 |  |  | 30 |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues |  |  |  |  |  |  |  |  | 2,780,087 |  |  |  |  |
Stock Issued During Period, Value, New Issues | $ |  |  |  |  |  |  |  |  | $ 8,100,000 |  |  |  |  |
Payments for Brokerage Fees | $ |  |  |  |  |  |  |  |  | $ 166,000 |  |  |  |  |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights |  |  |  |  |  |  |  |  |  |  |  |  | 0.1622 |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  | $ 6.17 |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The amount of cash paid for brokerage fees during the current period. This element is intended to represent the brokerage fees paid by and between financial industry participants. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585 + Details
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- Definition Amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Number of share instruments newly issued under a share-based compensation plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
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- Definition Percentage of vesting of share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer. + References No definition available. + Details
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