Note 9 - Employee Benefit Plans - Employee Allocations of Investments and Measurement Dates by Asset Category (Details)	Dec. 31, 2018	Dec. 31, 2017
Hecla Mining Company Retirement Plan [Member]
Allocation of investments	100.00%	100.00%
Lucky Friday Pension Plan [Member]
Allocation of investments	100.00%	100.00%
Cash [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	1.00%
Cash [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	1.00%
Large Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	15.00%	19.00%
Large Cap US Equity [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	15.00%	18.00%
Small Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	6.00%	9.00%
Small Cap US Equity [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	6.00%	10.00%
Debt Security, Government, Non-US [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	23.00%	27.00%
Debt Security, Government, Non-US [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	23.00%	26.00%
Fixed Income Funds [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	24.00%	21.00%
Fixed Income Funds [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	24.00%	20.00%
Real Estate [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	15.00%	14.00%
Real Estate [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	17.00%	15.00%
Hedge Funds [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	6.00%	5.00%
Hedge Funds [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	6.00%	6.00%
Common Stock [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	10.00%	5.00%
Common Stock [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	8.00%	5.00%