Note 5 - Income Taxes (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2013

Dec. 31, 2012

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Three Months Ended June 30,						Six Months Ended June 30,
	2013			2012			2013			2012
Current:
Federal	$	1,761		$	(144	)	$	3,992		$	3,528
State		(733	)		2			173			553
Foreign		115			115			230			230
Total current income tax provision (benefit)		1,143			(27	)		4,395			4,311
Deferred income tax provision (benefit)		(7,938	)		720			(3,775	)		3,697
Total income tax provision (benefit)	$	(6,795	)	$	693		$	620		$	8,008

	2012			2011		2010
Current:
Federal	$	7,411		$	3,823	$	10,063
State		(325	)		752		6,694
Foreign		459			459		459
Total current income tax provision		7,545			5,034		17,216
Federal and state deferred income tax (benefit) provision		1,334			76,944		(140,748	)
Total income tax (benefit) provision	$	8,879		$	81,978	$	(123,532	)

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

	2012			2011			2010
Domestic	$	37,025		$	244,833		$	(66,348	)
Foreign		(13,192	)		(11,691	)		(8,201	)
Total	$	23,833		$	233,142		$	(74,549	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2012					2011					2010
Computed “statutory” (benefit) provision	$	8,342		35	%	$	81,600		35	%	$	(26,092	)	(35	)%
Percentage depletion		(5,575	)	(24	)		(13,751	)	(6	)		(8,858	)	(12	)
Net increase (utilization) of U.S. and foreign tax loss carryforwards		3,837		16			3,822		2			2,713		3
Change in valuation allowance other than utilization		—		—			—		—			(88,069	)	(118	)
State taxes, net of federal taxes		1,110		5			10,890		5			(4,717	)	(6	)
Effect of U.S. AMT, foreign taxes other		1,165		5			(583	)	(1	)		1,491		2
	$	8,879		37	%	$	81,978		35	%	$	(123,532	)	(13	)%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	2012			2011
Deferred tax assets:
Accrued reclamation costs	$	45,653		$	62,225
Deferred exploration		32,396			18,585
Foreign net operating losses		20,247			20,234
Federal net operating losses		44,146			47,875
State net operating losses		668			2,445
AMT credit carryforwards		24,603			15,210
Pension and benefit obligation		12,488			9,940
Miscellaneous		17,437			16,002
Total deferred tax assets		197,638			192,516
Valuation allowance		(23,030	)		(22,895	)
Total deferred tax assets		174,608			169,621
Deferred tax liabilities:
Unrealized gain on derivatives contracts		(1,262	)		(13,293	)
Properties, plants and equipment		(57,583	)		(40,490	)
Total deferred tax liabilities		(58,845	)		(53,783	)
Net deferred tax asset	$	115,763		$	115,838

Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block]

		2,012			2,011			2,010
Balance at beginning of year	$	(22,895	)	$	(19,073	)	$	(104,429	)
Increase related to non-utilization of net operating loss carryforwards and non-recognition of deferred tax assets due to uncertainty of recovery		(3,837	)		(3,822	)		(2,713	)
Decrease related to net recognition of deferred tax assets		—			—			88,069
Decrease related to utilization and expiration of deferred tax assets, other		3,702			—			—
Balance at end of year	$	(23,030	)	$	(22,895	)	$	(19,073	)