Note 4 - Environmental and Reclamation Activities - Accrued Reclamation and Closure Cost Liability Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance at January 1, 2014	$ 95,538	$ 57,250	$ 105,191
Accruals for estimated costs	672	15,114	6,863
Accretion expense	3,191	1,904	3,089
Revision of estimated cash flows due to changes in reclamation plans	2,759	4,112	675
Payment of reclamation obligations	(17,704)	(1,544)	(58,568)
Balance at December 31, 2014	85,580	95,538	$ 57,250
Addition due to development and production at our San Sebastian unit		1,189
Revett Mining Company, Inc. [Member]
Liability addition due to acquisition of Revett		$ 17,513
Mines Management [Member]
Liability addition due to acquisition of Revett	$ 1,124