Note 4 - Environmental and Reclamation Activities (Details) - Liabilities Accrued for Reclamation and Closure Costs - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating properties:
Accrued reclamation and closure costs	$ 95,538	$ 57,250	$ 105,191	$ 113,215
Reclamation and closure costs, current	(20,989)	(1,631)
Reclamation and closure costs, long-term	74,549	55,619
Operating Properties [Member] | Greens Creek [Member]
Operating properties:
Accrued reclamation and closure costs	41,338	39,237
Operating Properties [Member] | Lucky Friday [Member]
Operating properties:
Accrued reclamation and closure costs	5,212	1,069
Operating Properties [Member] | Casa Berardi [Member]
Operating properties:
Accrued reclamation and closure costs	5,494	6,233
Operating Properties [Member] | San Sebastian Unit [Member]
Operating properties:
Accrued reclamation and closure costs	1,189
Non-operating Properties [Member] | Troy Mine [Member]
Operating properties:
Accrued reclamation and closure costs	17,295
Non-operating Properties [Member] | South Dakota and Colorado Superfund Sites [Member]
Operating properties:
Accrued reclamation and closure costs	16,300	1,200
Non-operating Properties [Member] | Johnny M [Member]
Operating properties:
Accrued reclamation and closure costs	5,830	5,830
Non-operating Properties [Member] | Republic [Member]
Operating properties:
Accrued reclamation and closure costs	774	1,389
Non-operating Properties [Member] | All Other Sites [Member]
Operating properties:
Accrued reclamation and closure costs	$ 2,106	$ 2,292