Note 5 - Income Taxes (Details) - Components of the Net Deferred Tax Asset - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Accrued reclamation costs	$ 26,473	$ 20,573
Deferred exploration	29,120	32,225
Foreign net operating losses	21,140	25,790
Domestic net operating losses	82,116	73,018
AMT credit carryforwards	11,607	14,698
Pension and benefit obligation	18,916	16,876
Foreign exchange gain	38,779	16,555
Miscellaneous	33,897	29,976
Total deferred tax assets	262,048	229,711
Valuation allowance	(115,806)	(32,094)	$ (27,155)	$ (23,030)
Total deferred tax assets	146,242	197,617
Deferred tax liabilities:
Miscellaneous	(2,394)	(7,620)
Properties, plants and equipment	(209,577)	(232,397)
Total deferred tax liabilities	(211,971)	(240,017)
Net deferred tax liability	$ (65,729)	$ (42,400)