Note 1 - Basis of Preparation of Financial Statements (Details Textual) - USD ($) $ in Millions		3 Months Ended
Mar. 31, 2020	Mar. 31, 2020
Casa Berardi [Member]
Suspension Costs		$ 0.9
Greens Creek [Member]
Suspension Costs from Quarantining Employee Per Week	$ 0.2

Amount of costs incurred per week from the employee quarantine.

No definition available.

Name:	hl_SuspensionCostsFromQuarantiningEmployeePerWeek
Namespace Prefix:	hl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration