Note 13 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	$ 58,768	$ 5,080
Additions to properties, plants, and equipment	(90,697)	(112,806)
Acquisition of Aurizon Mines		(321,117)
Other investing activities, net	4,201	(3,876)
Dividends paid to stockholders	(3,043)	(5,548)
Borrowings on debt		490,000
Proceeds from (payments on) debt	(6,893)	(5,171)
Other financing activity, net	49,973	(1,530)
Effect of exchange rates on cash	(2,124)	1,820
Changes in cash and cash equivalents	10,185	46,852
Cash and cash equivalents	222,360	237,836
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	(31,968)
Other financing activity, net	31,968
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	37,533	(7,020)
Additions to properties, plants, and equipment	(1,057)	(1,169)
Acquisition of Aurizon Mines		(498,705)
Dividends paid to stockholders	(3,043)	(5,548)
Borrowings on debt		490,000
Other financing activity, net	(7,965)	6,431
Changes in cash and cash equivalents	25,468	(16,011)
Cash and cash equivalents	151,739	116,255
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	32,896	57,833
Additions to properties, plants, and equipment	(58,472)	(88,807)
Other investing activities, net	358	103
Proceeds from (payments on) debt	(6,878)	(5,171)
Other financing activity, net	40,292	7,936
Changes in cash and cash equivalents	8,196	(28,106)
Cash and cash equivalents	48,205	29,864
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	20,307	(45,733)
Additions to properties, plants, and equipment	(31,168)	(22,830)
Acquisition of Aurizon Mines		177,588
Other investing activities, net	3,843	(3,979)
Proceeds from (payments on) debt	(15)
Other financing activity, net	(14,322)	(15,897)
Effect of exchange rates on cash	(2,124)	1,820
Changes in cash and cash equivalents	(23,479)	90,969
Cash and cash equivalents	$ 22,416	$ 91,717