Note 10 - Stockholders' Equity (Details Textual) - USD ($)		1 Months Ended	3 Months Ended			12 Months Ended			36 Months Ended	48 Months Ended	58 Months Ended	104 Months Ended
	Jul. 20, 2018	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2020	Feb. 16, 2021	Feb. 23, 2016	May 08, 2012	Jun. 30, 2010
Common Stock, Shares Authorized (in shares)			750,000,000		750,000,000	750,000,000	750,000,000		750,000,000	750,000,000	750,000,000	750,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.25		$ 0.25	$ 0.25	$ 0.25		$ 0.25	$ 0.25	$ 0.25	$ 0.25
Common Stock, Shares, Issued, Total (in shares)			538,487,415			538,487,415			538,487,415	538,487,415	538,487,415	538,487,415
Treasury Stock, Shares, Ending Balance (in shares)			6,821,044		6,287,271	6,821,044	6,287,271		6,821,044	6,821,044	6,821,044	6,821,044
Common Stock, Shares, Outstanding, Ending Balance (in shares)			531,666,371			531,666,371			531,666,371	531,666,371	531,666,371	531,666,371
Average Realized Silver Price, Minimum Dividend, Threshold (in dollars per share)			$ 25		$ 30	$ 25	$ 30		$ 25	$ 25	$ 25	$ 25
Average Realized Silver Price Per Ounce			$ 25.16	$ 25.32
At-the-market Equity Distribution Agreement, Maximum Proceeds														$ 75,000,000
Stock Issued During Period, Shares, New Issues (in shares)					21,410,231		21,410,000	2,565,000			28,583,845
Proceeds from Issuance of Common Stock					$ 49,000,000.0	$ 0	$ 49,019,000	$ 6,744,000			$ 73,500,000
Payments of Stock Issuance Costs					$ 1,000,000.0						$ 1,500,000
Preferred Stock, Shares Authorized (in shares)			5,000,000		5,000,000	5,000,000	5,000,000		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		$ 0.25	$ 0.25	$ 0.25	$ 0.25
Preferred Stock, Shares Outstanding, Ending Balance (in shares)			157,816		157,816	157,816	157,816		157,816	157,816	157,816	157,816
Percent of Shareholders' Consent Needed to Create or Issue Stock Ranking Senior to Series B Preferred Stock			66.67%			66.67%			66.67%	66.67%	66.67%	66.67%
Preferred Stock, Liquidation Preference, Value			$ 7,891,000		$ 7,891,000	$ 7,891,000	$ 7,891,000		$ 7,891,000	$ 7,891,000	$ 7,891,000	$ 7,891,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 3,500,000			$ 3,500,000			$ 3,500,000	$ 3,500,000	$ 3,500,000	$ 3,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			3,936,134		3,997,168	3,936,134	3,997,168		3,936,134	3,936,134	3,936,134	3,936,134
Share-based Compensation Arrangement by Share-based Payment Award, Measurement Period Used to Value Performance-based Awards (Year)						3 years
Stock Issued During Period, Shares, Treasury Stock Reissued (in shares)						650,000
Stock Issued During Period, Value, Treasury Stock Reissued						$ 1,970,000
Hecla Charitable Foundation [Member]
Stock Issued During Period, Shares, Treasury Stock Reissued (in shares)		650,000
Stock Issued During Period, Value, Treasury Stock Reissued		$ 2,000,000.0
Treasury Stock, Reissued, Weighted Average Cost Basis (in dollars per share)		$ 3.41
Treasury Stock Reissued at Lower than Repurchase Price		$ 2,200,000
Klondex Mines Ltd [Member]
Stock Issued During Period, Shares, New Issues (in shares)	75,276,176
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 8.02
Warrants in Connection with Klondex Mines Acquisition [Member]
Class of Warrant or Right, Issued During Period (in shares)	4,136,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1
Warrants in Connection with Klondex Mines Acquisition Expiring April 2032 [Member]
Class of Warrant or Right, Outstanding (in shares)	2,068,000
Warrants in Connection with Klondex Mines Acquisition Expiring February 2029 [Member]
Class of Warrant or Right, Outstanding (in shares)	2,068,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 1.57
Satisfy Withholding Obligations [Member]
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)						$ 2.32	$ 2.10
Stock Repurchased During Period, Shares (in shares)						1,183,773	1,060,480
Stock Repurchased During Period, Value						$ 2,700,000	$ 2,200,000
2010 Stock Incentive Plan [Member]
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)			12,443,518			12,443,518			12,443,518	12,443,518	12,443,518	12,443,518
Directors Stock Plan [Member]
Share-based Payment Arrangement, Expense						$ 1,500,000	500,000	$ 600,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)			2,476,644			2,476,644			2,476,644	2,476,644	2,476,644	2,476,644
Share-Based Compensation Arrangement by Share-Based Payment Award, Method of Measuring Cost of Award Participant, Numerator							$ 120,000
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture (in shares)						391,244	252,819	161,630
Share-based Payment Arrangement [Member]
Share-based Payment Arrangement, Expense						$ 6,500,000	$ 5,700,000	$ 6,300,000
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expense						3,600,000				$ 5,100,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount			$ 4,900,000			4,900,000			$ 4,900,000	4,900,000	$ 4,900,000	$ 4,900,000
Performance Shares [Member]
Share-based Payment Arrangement, Expense									39,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount			$ 100,000			$ 100,000			$ 100,000	$ 100,000	$ 100,000	$ 100,000
Series B Preferred Stock [Member]
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in dollars per share)						$ 3.50
Preferred Stock, Redemption Price Per Share (in dollars per share)			$ 50			50			$ 50	$ 50	$ 50	$ 50
Preferred Stock, Liquidation Preference Per Share (in dollars per share)			$ 50			$ 50			$ 50	$ 50	$ 50	$ 50
Preferred Stock, Liquidation Preference, Value			$ 7,900,000			$ 7,900,000			$ 7,900,000	$ 7,900,000	$ 7,900,000	$ 7,900,000
Preferred Stock, Voting Rights						one
Preferred Stock Conversion Price (in dollars per share)			$ 15.55			$ 15.55			$ 15.55	$ 15.55	$ 15.55	$ 15.55
Preferred Stock Conversion Rate (in dollars per share)			$ 3.2154			$ 3.2154			$ 3.2154	$ 3.2154	$ 3.2154	$ 3.2154
Subsequent Event [Member]
Share Price (in dollars per share)													$ 6.13
Common Stock Repurchase Program [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)															20,000,000
Cumulative Stock Repurchased (in shares)			934,100			934,100			934,100	934,100	934,100	934,100
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)												$ 3.99
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)			19,100,000			19,100,000			19,100,000	19,100,000	19,100,000	19,100,000
Treasury Stock, Shares, Acquired (in shares)						0
Minimum [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)						$ 0.01	$ 0.01
Maximum [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)						$ 0.015