Note 6 - Business Segments - Identifiable Assets by Reporting Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Identifiable assets:
Identifiable assets	$ 2,398,091	$ 2,364,957
Greens Creek [Member]
Identifiable assets:
Identifiable assets	669,042	671,960
Lucky Friday [Member]
Identifiable assets:
Identifiable assets	432,369	432,400
Casa Berardi [Member]
Identifiable assets:
Identifiable assets	802,017	804,505
San Sebastian [Member]
Identifiable assets:
Identifiable assets	67,576	62,198
Other Segments [Member]
Identifiable assets:
Identifiable assets	$ 427,087	$ 393,894