Note 14 - Condensed Consolidating Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Parent Company [Member]
Revenues	$ (5,659)	$ 1,081	$ (11,794)	$ 1,393
Cost of sales
Depreciation, depletion, amortization
General and administrative	(6,474)	(4,373)	(11,714)	(8,815)
Exploration and pre-development	(113)	(122)	(158)	(339)
Loss on derivative contracts	(6)	(2,055)	(6)	4,905
Acquisition costs	(394)	(887)	(394)	(2,055)
Equity in earnings of subsidiaries	37,111	(738)	16,120	39,304
Other (expense) income	(349)	(19,573)	31,444	(48,508)
Income (loss) before income taxes	24,116	(26,667)	23,498	(14,115)
(Provision) benefit from income taxes
Net income (loss)	24,116	(26,667)	23,498	(14,115)
Preferred stock dividends	(138)	(138)	(276)	(276)
Income (loss) applicable to common stockholders	23,978	(26,805)	23,222	(14,391)
Changes in comprehensive income (loss)	1,239	(1,156)	2,304	780
Comprehensive income (loss)	25,355	(27,823)	25,802	(13,335)
Guarantor Subsidiaries [Member]
Revenues	87,992	67,531	169,261	154,465
Cost of sales	(47,203)	(41,512)	(93,956)	(92,949)
Depreciation, depletion, amortization	(15,238)	(16,452)	(31,844)	(33,063)
General and administrative	(3,679)	(3,392)	(8,202)	(7,285)
Exploration and pre-development	(1,360)	(1,445)	(2,647)	(2,579)
Loss on derivative contracts		(92)
Acquisition costs	(8)		(8)	(92)
Equity in earnings of subsidiaries
Other (expense) income	2,623	3,499	6,959	7,066
Income (loss) before income taxes	23,127	8,137	39,563	25,563
(Provision) benefit from income taxes	(8,386)	(1,956)	(13,219)	(6,902)
Net income (loss)	14,741	6,181	26,344	18,661
Preferred stock dividends
Income (loss) applicable to common stockholders	14,741	6,181	26,344	18,661
Changes in comprehensive income (loss)		183	8	(11)
Comprehensive income (loss)	14,741	6,364	26,352	18,650
Non-Guarantor Subsidiaries [Member]
Revenues	88,969	35,585	144,852	67,431
Cost of sales	(35,750)	(26,055)	(63,317)	(48,583)
Depreciation, depletion, amortization	(14,659)	(10,714)	(23,928)	(19,357)
General and administrative	(206)	(531)	(657)	(916)
Exploration and pre-development	(2,410)	(4,643)	(4,432)	(8,428)
Loss on derivative contracts
Acquisition costs
Equity in earnings of subsidiaries
Other (expense) income	(8,732)	(22,544)	(44,250)	8,462
Income (loss) before income taxes	27,212	(28,902)	8,268	(1,391)
(Provision) benefit from income taxes	(4,842)	21,983	(18,492)	22,034
Net income (loss)	22,370	(6,919)	(10,224)	20,643
Preferred stock dividends
Income (loss) applicable to common stockholders	22,370	(6,919)	(10,224)	20,643
Changes in comprehensive income (loss)	1,193	(1,264)	2,253	787
Comprehensive income (loss)	23,563	(8,183)	(7,971)	21,430
Consolidation, Eliminations [Member]
Revenues
Cost of sales
Depreciation, depletion, amortization
General and administrative
Exploration and pre-development
Loss on derivative contracts
Acquisition costs
Equity in earnings of subsidiaries	(37,111)	738	(16,120)	(39,304)
Other (expense) income	(1,732)	19,895	(18,561)	16,439
Income (loss) before income taxes	(38,843)	20,633	(34,681)	(22,865)
(Provision) benefit from income taxes	1,732	(19,895)	18,561	(16,439)
Net income (loss)	(37,111)	738	(16,120)	(39,304)
Preferred stock dividends
Income (loss) applicable to common stockholders	(37,111)	738	(16,120)	(39,304)
Changes in comprehensive income (loss)	(1,193)	1,082	(2,261)	(775)
Comprehensive income (loss)	(38,304)	1,820	(18,381)	(40,079)
Consolidated [Member]
Revenues	171,302	104,197	302,319	223,289
Cost of sales	(82,953)	(67,567)	(157,273)	(141,532)
Depreciation, depletion, amortization	(29,897)	(27,166)	(55,772)	(52,420)
General and administrative	(10,359)	(8,296)	(20,573)	(17,016)
Exploration and pre-development	(3,883)	(6,210)	(7,237)	(11,346)
Loss on derivative contracts	(6)	(2,147)	(6)	4,905
Acquisition costs	(402)	(887)	(402)	(2,147)
Equity in earnings of subsidiaries
Other (expense) income	(8,190)	(18,723)	(24,408)	(16,541)
Income (loss) before income taxes	35,612	(26,799)	36,648	(12,808)
(Provision) benefit from income taxes	(11,496)	132	(13,150)	(1,307)
Net income (loss)	24,116	(26,667)	23,498	(14,115)
Preferred stock dividends	(138)	(138)	(276)	(276)
Income (loss) applicable to common stockholders	23,978	(26,805)	23,222	(14,391)
Changes in comprehensive income (loss)	1,239	(1,155)	2,304	781
Comprehensive income (loss)	25,355	(27,822)	25,802	(13,334)
Revenues	171,302	104,197	302,319	223,289
Cost of sales	82,953	67,567	157,273	141,532
Depreciation, depletion, amortization	29,897	27,166	55,772	52,420
General and administrative	10,359	8,296	20,573	17,016
Loss on derivative contracts	(6)	(887)	(6)	4,905
Acquisition costs	402	2,147	402	2,147
Income (loss) before income taxes	35,612	(26,799)	36,648	(12,808)
(Provision) benefit from income taxes	11,496	(132)	13,150	1,307
Net income (loss)	24,116	(26,667)	23,498	(14,115)
Preferred stock dividends	138	138	276	276
Income (loss) applicable to common stockholders	23,978	(26,805)	23,222	(14,391)
Comprehensive income (loss)	$ 25,355	$ (27,822)	$ 25,802	$ (13,334)