Note 14 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements, Captions [Line Items]
Revenues	$ 104,941	$ 135,507	$ 328,230	$ 378,796
Cost of sales	(79,273)	(86,680)	(220,805)	(235,460)
Depreciation, depletion, amortization	(28,229)	(26,804)	(80,649)	(80,342)
General and administrative	(9,461)	(7,884)	(26,477)	(23,984)
Gain/(loss) on derivative contracts	3,347	(411)	8,252	(2,560)
Acquisition costs	(15)		(2,162)
Income (loss) before income taxes	(15,390)	3,856	(28,198)	(143)
(Provision) benefit from income taxes	5,500	(180)	4,193	1,062
Net income (loss)	(9,890)	3,676	(24,005)	919
Comprehensive income (loss)	(10,281)	5,952	(23,615)	2,357
Preferred stock dividends	(138)	(138)	(414)	(414)
Income (loss) applicable to common stockholders	(10,028)	3,538	(24,419)	505
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Equity in earnings (loss) of subsidiaries	11,300	(96,349)	(28,005)	(32,864)
Other (expense) income	(21,339)	68,017	(4,899)	(11,398)
Income (loss) before income taxes	(10,039)	(28,332)	(32,904)	(44,262)
(Provision) benefit from income taxes	21,338	(68,017)	4,899	11,398
Net income (loss)	11,299	(96,349)	(28,005)	(32,864)
Changes in comprehensive income (loss)	306	(2,307)	(470)	(2,752)
Comprehensive income (loss)	11,605	(98,656)	(28,475)	(35,616)
Income (loss) applicable to common stockholders	11,299	(96,349)	(28,005)	(32,864)
Consolidated [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	104,941	135,507	328,230	378,796
Cost of sales	(79,273)	(86,680)	(220,805)	(235,460)
Depreciation, depletion, amortization	(28,229)	(26,804)	(80,649)	(80,342)
General and administrative	(9,461)	(7,884)	(26,477)	(23,984)
Exploration and pre-development	(7,236)	(6,188)	(18,582)	(14,333)
Gain/(loss) on derivative contracts	3,347	(411)	8,252	(2,560)
Acquisition costs	(15)		(2,162)
Other (expense) income	536	(3,684)	(16,005)	(22,260)
Income (loss) before income taxes	(15,390)	3,856	(28,198)	(143)
(Provision) benefit from income taxes	5,500	(180)	4,193	1,062
Net income (loss)	(9,890)	3,676	(24,005)	919
Changes in comprehensive income (loss)	(391)	2,276	390	1,438
Comprehensive income (loss)	(10,281)	5,952	(23,615)	2,357
Preferred stock dividends	(138)	(138)	(414)	(414)
Income (loss) applicable to common stockholders	(10,028)	3,538	(24,419)	505
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	4,663	1,444	6,056	(2,029)
General and administrative	(4,965)	(4,048)	(13,780)	(13,207)
Exploration and pre-development	(210)	(4)	(549)	(56)
Gain/(loss) on derivative contracts	3,347	(411)	8,252	(2,560)
Acquisition costs	1,538		(517)
Equity in earnings (loss) of subsidiaries	(11,300)	96,349	28,005	32,864
Other (expense) income	(2,963)	(89,654)	(51,472)	(14,093)
Income (loss) before income taxes	(9,890)	3,676	(24,005)	919
Net income (loss)	(9,890)	3,676	(24,005)	919
Changes in comprehensive income (loss)	(390)	2,276	390	1,438
Comprehensive income (loss)	(10,280)	5,952	(23,615)	2,357
Preferred stock dividends	(138)	(138)	(414)	(414)
Income (loss) applicable to common stockholders	(10,028)	3,538	(24,419)	505
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	63,604	94,202	218,069	260,577
Cost of sales	(53,375)	(57,995)	(146,324)	(151,145)
Depreciation, depletion, amortization	(16,669)	(17,205)	(49,732)	(53,706)
General and administrative	(4,131)	(3,590)	(11,416)	(9,819)
Exploration and pre-development	(2,800)	(3,085)	(5,379)	(5,826)
Acquisition costs	(1,553)		(1,645)
Other (expense) income	3,289	3,503	10,355	4,781
Income (loss) before income taxes	(11,635)	15,830	13,928	44,862
(Provision) benefit from income taxes	1,606	(2,878)	(5,296)	(10,486)
Net income (loss)	(10,029)	12,952	8,632	34,376
Changes in comprehensive income (loss)	(5)	78	(15)	303
Comprehensive income (loss)	(10,034)	13,030	8,617	34,679
Income (loss) applicable to common stockholders	(10,029)	12,952	8,632	34,376
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	36,674	39,861	104,105	120,248
Cost of sales	(25,898)	(28,685)	(74,481)	(84,315)
Depreciation, depletion, amortization	(11,560)	(9,599)	(30,917)	(26,636)
General and administrative	(365)	(246)	(1,281)	(958)
Exploration and pre-development	(4,226)	(3,099)	(12,654)	(8,451)
Other (expense) income	21,549	14,450	30,011	(1,550)
Income (loss) before income taxes	16,174	12,682	14,783	(1,662)
(Provision) benefit from income taxes	(17,444)	70,715	4,590	150
Net income (loss)	(1,270)	83,397	19,373	(1,512)
Changes in comprehensive income (loss)	(302)	2,229	485	2,449
Comprehensive income (loss)	(1,572)	85,626	19,858	937
Income (loss) applicable to common stockholders	$ (1,270)	$ 83,397	$ 19,373	$ (1,512)