Note 9 - Employee Benefit Plans - Employee Allocations of Investments and Measurement Dates by Asset Category (Details)	Dec. 31, 2020	Dec. 31, 2019
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	0.00%	6.00%
Cash [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	0.00%	6.00%
Large Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	17.00%	14.00%
Large Cap US Equity [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	16.00%	14.00%
Small Cap US Equity [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	8.00%	7.00%
Small Cap US Equity [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	9.00%	7.00%
Debt Security, Government, Non-US [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	26.00%	22.00%
Debt Security, Government, Non-US [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	26.00%	22.00%
Fixed Income Funds [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	21.00%	19.00%
Fixed Income Funds [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	21.00%	19.00%
Real Estate [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	11.00%	14.00%
Real Estate [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	12.00%	15.00%
Hedge Funds [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	5.00%	5.00%
Hedge Funds [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	4.00%	5.00%
Common Stock [Member] | Hecla Mining Company Retirement Plan [Member]
Allocation of investments	12.00%	13.00%
Common Stock [Member] | Lucky Friday Pension Plan [Member]
Allocation of investments	12.00%	12.00%