Note 13 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	$ 57,029,000	$ 10,275,000
Cash flows from investing activities:
Additions to properties, plants, and equipment	(57,461,000)	(60,291,000)
Acquisition of Aurizon Mines		(321,117,000)
Other investing activities, net	4,572,000	(3,786,000)
Cash flows from financing activities:
Dividends paid to stockholders	(1,991,000)	(4,553,000)
Borrowings on debt		490,000,000
Payments on debt	(4,525,000)	(3,425,000)
Other financing activity	12,034,000	(1,712,000)
Effect of exchange rate changes on cash	250,000
Changes in cash and cash equivalents	9,908,000	105,391,000
Cash and cash equivalents	222,083,000	296,375,000
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	1,574,000
Cash flows from financing activities:
Other financing activity	(1,574,000)
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	10,632,000	(7,524,000)
Cash flows from investing activities:
Additions to properties, plants, and equipment	(736,000)	(229,000)
Acquisition of Aurizon Mines		(498,705,000)
Cash flows from financing activities:
Dividends paid to stockholders	(1,991,000)	(4,553,000)
Borrowings on debt		490,000,000
Other financing activity	26,198,000	(2,706,000)
Changes in cash and cash equivalents	34,103,000	(23,717,000)
Cash and cash equivalents	160,374,000
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	46,829,000	54,148,000
Cash flows from investing activities:
Additions to properties, plants, and equipment	(32,891,000)	(54,128,000)
Other investing activities, net	238,000	102,000
Cash flows from financing activities:
Payments on debt	(4,525,000)	(3,425,000)
Other financing activity	(11,021,000)	1,681,000
Changes in cash and cash equivalents	(1,370,000)	(1,622,000)
Cash and cash equivalents	38,639,000
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	(2,006,000)	(36,349,000)
Cash flows from investing activities:
Additions to properties, plants, and equipment	(23,834,000)	(5,934,000)
Acquisition of Aurizon Mines		177,588,000
Other investing activities, net	4,334,000	(3,888,000)
Cash flows from financing activities:
Other financing activity	(1,569,000)	(687,000)
Effect of exchange rate changes on cash	250,000
Changes in cash and cash equivalents	(22,825,000)	130,730,000
Cash and cash equivalents	23,070,000
Ending Balance [Member] | Parent Company [Member]
Cash flows from financing activities:
Cash and cash equivalents	160,374,000	108,549,000
Ending Balance [Member] | Guarantor Subsidiaries [Member]
Cash flows from financing activities:
Cash and cash equivalents	38,639,000	55,453,000
Ending Balance [Member] | Non-Guarantor Subsidiaries [Member]
Cash flows from financing activities:
Cash and cash equivalents	23,070,000	132,373,000
Ending Balance [Member]
Cash flows from financing activities:
Cash and cash equivalents	$ 222,083,000	$ 296,375,000