Note 4 - Environmental and Reclamation Activities - Liabilities Accrued for Reclamation and Closure Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating properties:
Reclamation and closure costs	$ 85,580	$ 95,538	$ 57,250	$ 105,191
Non-operating properties:
Reclamation and closure costs	85,580	95,538	$ 57,250	$ 105,191
Reclamation and closure costs, current	(5,653)	(20,989)
Reclamation and closure costs, long-term	79,927	74,549
Operating Properties [Member] | Greens Creek [Member]
Operating properties:
Reclamation and closure costs	39,014	41,338
Non-operating properties:
Reclamation and closure costs	39,014	41,338
Operating Properties [Member] | Lucky Friday [Member]
Operating properties:
Reclamation and closure costs	9,194	5,212
Non-operating properties:
Reclamation and closure costs	9,194	5,212
Operating Properties [Member] | Casa Berardi [Member]
Operating properties:
Reclamation and closure costs	5,475	5,494
Non-operating properties:
Reclamation and closure costs	5,475	5,494
Operating Properties [Member] | San Sebastian [Member]
Operating properties:
Reclamation and closure costs	5,425	1,189
Non-operating properties:
Reclamation and closure costs	5,425	1,189
Non-Operating Properties [Member] | Troy Mine [Member]
Operating properties:
Reclamation and closure costs	16,167	17,295
Non-operating properties:
Reclamation and closure costs	16,167	17,295
Non-Operating Properties [Member] | South Dakota and Colorado Superfund Sites [Member]
Operating properties:
Reclamation and closure costs		16,300
Non-operating properties:
Reclamation and closure costs		16,300
Non-Operating Properties [Member] | Johnny M Mine Area near San Mateo, New Mexico [Member]
Operating properties:
Reclamation and closure costs	5,830	5,830
Non-operating properties:
Reclamation and closure costs	5,830	5,830
Non-Operating Properties [Member] | Republic [Member]
Operating properties:
Reclamation and closure costs	1,500	774
Non-operating properties:
Reclamation and closure costs	1,500	774
Non-Operating Properties [Member] | All Other Sites [Member]
Operating properties:
Reclamation and closure costs	2,975	2,106
Non-operating properties:
Reclamation and closure costs	$ 2,975	$ 2,106