Note 2 - Investments and Restricted Cash (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended
	Jun. 30, 2015	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Note 2 - Investments and Restricted Cash (Details) [Line Items]
Long-term Investments		$ 2,003			$ 2,003		$ 4,920
Available-for-sale Securities, Amortized Cost Basis		4,200			4,200		7,300
Other than Temporary Impairment Losses, Investments			$ 2,800
Payments to Acquire Investments			$ 900		947	$ 580
Unrealized Gain (Loss) on Investments		(100)		$ (2,830)	(3,226)	$ (2,750)
Restricted Investments		1,000			1,000		$ 900
Non-Current Investments Held Having Net Loss Position [Member]
Note 2 - Investments and Restricted Cash (Details) [Line Items]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(2,200)			(2,200)
Non-Current Investments Held Having Net Gain Position [Member]
Note 2 - Investments and Restricted Cash (Details) [Line Items]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		$ 6			$ 6
Revett Mining Company, Inc. [Member]
Note 2 - Investments and Restricted Cash (Details) [Line Items]
Increase (Decrease) in Cost Basis of Investments	$ (500)
Unrealized Gain (Loss) on Investments	$ (200)