Note 13 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Income Statements, Captions [Line Items]
Revenues	$ 117,502	$ 85,330	$ 243,289	$ 161,780
Cost of sales	(71,039)	(60,008)	(148,780)	(96,833)
Depreciation, depletion, amortization	(27,735)	(20,211)	(53,538)	(34,218)
General and administrative	(8,159)	(7,482)	(16,100)	(14,421)
Exploration and pre-development	(3,577)	(10,733)	(8,146)	(22,017)
Gain/loss on derivative contracts	(11,601)	6,541	(2,149)	28,080
Aurizon acquisition costs		(20,308)		(25,600)
Other (expense) income	(14,815)	(4,782)	(18,576)	(9,915)
Income (loss) before income taxes	(19,424)	(31,653)	(4,000)	(13,144)
(Provision) benefit from income taxes	5,025	6,795	1,242	(620)
Net income (loss)	(14,399)	(24,858)	(2,758)	(13,764)
Changes in comprehensive income (loss)	(2,188)	(1,944)	(838)	(4,775)
Comprehensive income (loss)	(16,587)	(26,802)	(3,596)	(18,539)
Preferred stock dividends	(138)	(138)	(276)	(276)
Income (loss) applicable to common stockholders	(14,537)	(24,996)	(3,034)	(14,040)
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Equity in earnings of subsidiaries	81,189	13,625	63,486	14,698
Other (expense) income	(76,112)	(1,950)	(79,415)
Income (loss) before income taxes	5,077	11,675	(15,929)	14,698
(Provision) benefit from income taxes	76,112	263	79,415	(1,687)
Net income (loss)	81,189	11,938	63,486	13,011
Changes in comprehensive income (loss)	928	(2,832)	(445)
Comprehensive income (loss)	82,117	9,106	63,041	13,011
Income (loss) applicable to common stockholders	81,189	11,938	63,486	13,011
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	(3,454)	372	(3,473)	2,785
General and administrative	(4,529)	(3,993)	(9,159)	(7,465)
Exploration and pre-development	(8)	(253)	(52)	(417)
Gain/loss on derivative contracts	(11,601)	6,541	(2,149)	28,080
Aurizon acquisition costs		(10,650)		(14,148)
Equity in earnings of subsidiaries	(81,189)	(13,625)	(63,486)	(14,698)
Other (expense) income	86,382	(3,250)	75,561	(7,901)
Income (loss) before income taxes	(14,399)	(24,858)	(2,758)	(13,764)
Net income (loss)	(14,399)	(24,858)	(2,758)	(13,764)
Changes in comprehensive income (loss)	(2,188)	(1,944)	(838)	(4,775)
Comprehensive income (loss)	(16,587)	(26,802)	(3,596)	(18,539)
Preferred stock dividends	(138)	(138)	(276)	(276)
Income (loss) applicable to common stockholders	(14,537)	(24,996)	(3,034)	(14,040)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	82,665	74,838	166,375	148,875
Cost of sales	(43,217)	(51,777)	(93,150)	(88,602)
Depreciation, depletion, amortization	(19,280)	(16,887)	(36,501)	(30,894)
General and administrative	(3,221)	(3,137)	(6,229)	(6,547)
Exploration and pre-development	(1,784)	(8,553)	(2,742)	(16,748)
Aurizon acquisition costs		1,422
Other (expense) income	870	3,643	1,278	1,943
Income (loss) before income taxes	16,033	(451)	29,031	8,027
(Provision) benefit from income taxes	(4,722)	211	(7,608)	(5,254)
Net income (loss)	11,311	(240)	21,423	2,773
Changes in comprehensive income (loss)	168	4,257	225	3,830
Comprehensive income (loss)	11,479	4,017	21,648	6,603
Income (loss) applicable to common stockholders	11,311	(240)	21,423	2,773
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	38,291	10,120	80,387	10,120
Cost of sales	(27,822)	(8,231)	(55,630)	(8,231)
Depreciation, depletion, amortization	(8,455)	(3,324)	(17,037)	(3,324)
General and administrative	(409)	(352)	(712)	(409)
Exploration and pre-development	(1,785)	(1,927)	(5,352)	(4,852)
Aurizon acquisition costs		(11,080)		(11,452)
Other (expense) income	(25,955)	(3,225)	(16,000)	(3,957)
Income (loss) before income taxes	(26,135)	(18,019)	(14,344)	(22,105)
(Provision) benefit from income taxes	(66,365)	6,321	(70,565)	6,321
Net income (loss)	(92,500)	(11,698)	(84,909)	(15,784)
Changes in comprehensive income (loss)	(1,096)	(1,425)	220	(3,830)
Comprehensive income (loss)	(93,596)	(13,123)	(84,689)	(19,614)
Income (loss) applicable to common stockholders	$ (92,500)	$ (11,698)	$ (84,909)	$ (15,784)