Note 5 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Valuation Allowance		$ 78,684,000		$ 99,602,000	$ 115,806,000	$ 32,094,000
Deferred Tax Liabilities, Net		120,037,000		87,012,000
Liability Related to Withholding Taxes on Foreign Earnings Repatriated		$ 300,000
Foreign Earnings Repatriated				0
Operating Loss Carryforwards Expiration Period		20 years
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation		$ 0		22,000,000
Deferred Tax Assets, Net Operating Loss		5,000,000
Unrecognized Tax Benefits		$ 0		$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%	35.00%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			$ 30,000,000
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Domestic Tax Authority [Member]
Deferred Tax Assets, Valuation Allowance		$ 76,000,000
Operating Loss Carryforwards		506,000,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards		4,000,000
Foreign Tax Authority [Member] | Hecla Canada Limited [Member] | Canada Revenue Agency [Member]
Deferred Tax Assets, Valuation Allowance		2,000,000
Foreign Tax Authority [Member] | Minera Hecla S.A. [Member] | Mexican Tax Authority [Member]
Deferred Tax Assets, Valuation Allowance		1,000,000
Foreign Tax Authority [Member] | Hecla Quebec. Inc [Member] | Canada Revenue Agency [Member]
Deferred Tax Assets, Valuation Allowance		0
State and Local Jurisdiction [Member]
Operating Loss Carryforwards		366,000,000
Reclassification From Current Deferred Tax Assets to Non-Current Deferred Tax Assets [Member] | As of December 31, 2016 [Member]
Prior Period Reclassification Adjustment		12,300,000
Reclassification From Current Deferred Tax Liabilities to Non-Current Deferred Tax Liabilities [Member] | As of December 31, 2016 [Member]
Prior Period Reclassification Adjustment		$ 1,300,000