Note 13 - Condensed Consolidating Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Parent Company [Member]
Revenues	$ (6,135)	$ 312
Cost of sales
Depreciation, depletion, amortization
General and administrative	$ (5,240)	$ (4,442)
Exploration and pre-development	$ (45)	(217)
Gain on derivative contracts		5,792
Equity in earnings of subsidiaries	$ (20,991)	40,042
Other (expense) income	31,793	(28,935)
Income (loss) before income taxes	$ (618)	$ 12,552
(Provision) benefit from income taxes
Net income (loss)	$ (618)	$ 12,552
Preferred stock dividends	(138)	(138)
Income (loss) applicable to common stockholders	(756)	12,414
Changes in comprehensive income (loss)	1,065	1,936
Comprehensive income (loss)	447	14,488
Equity in earnings (loss) of subsidiaries	(20,991)	40,042
Guarantor Subsidiaries [Member]
Revenues	81,269	86,934
Cost of sales	(46,753)	(51,437)
Depreciation, depletion, amortization	(16,606)	(16,611)
General and administrative	(4,523)	(3,893)
Exploration and pre-development	$ (1,287)	$ (1,134)
Gain on derivative contracts
Equity in earnings of subsidiaries
Other (expense) income	$ 4,336	$ 3,567
Income (loss) before income taxes	16,436	17,426
(Provision) benefit from income taxes	(4,833)	(4,946)
Net income (loss)	$ 11,603	$ 12,480
Preferred stock dividends
Income (loss) applicable to common stockholders	$ 11,603	$ 12,480
Changes in comprehensive income (loss)	8	(194)
Comprehensive income (loss)	$ 11,611	$ 12,286
Equity in earnings (loss) of subsidiaries
Non-Guarantor Subsidiaries [Member]
Revenues	$ 55,883	$ 31,846
Cost of sales	(27,567)	(22,528)
Depreciation, depletion, amortization	(9,269)	(8,643)
General and administrative	(451)	(385)
Exploration and pre-development	$ (2,022)	$ (3,785)
Gain on derivative contracts
Equity in earnings of subsidiaries
Other (expense) income	$ (35,518)	$ 31,006
Income (loss) before income taxes	(18,944)	27,511
(Provision) benefit from income taxes	(13,650)	51
Net income (loss)	$ (32,594)	$ 27,562
Preferred stock dividends
Income (loss) applicable to common stockholders	$ (32,594)	$ 27,562
Changes in comprehensive income (loss)	1,060	2,051
Comprehensive income (loss)	$ (31,534)	$ 29,613
Equity in earnings (loss) of subsidiaries
Consolidation, Eliminations [Member]
Revenues
Cost of sales
Depreciation, depletion, amortization
General and administrative
Exploration and pre-development
Gain on derivative contracts
Equity in earnings of subsidiaries	$ 20,991	$ (40,042)
Other (expense) income	(16,829)	(3,456)
Income (loss) before income taxes	4,162	(43,498)
(Provision) benefit from income taxes	16,829	3,456
Net income (loss)	$ 20,991	$ (40,042)
Preferred stock dividends
Income (loss) applicable to common stockholders	$ 20,991	$ (40,042)
Changes in comprehensive income (loss)	(1,068)	(1,857)
Comprehensive income (loss)	19,923	(41,899)
Equity in earnings (loss) of subsidiaries	20,991	(40,042)
Consolidated [Member]
Revenues	131,017	119,092
Cost of sales	(74,320)	(73,965)
Depreciation, depletion, amortization	(25,875)	(25,254)
General and administrative	(10,214)	(8,720)
Exploration and pre-development	$ (3,354)	(5,136)
Gain on derivative contracts		$ 5,792
Equity in earnings of subsidiaries
Other (expense) income	$ (16,218)	$ 2,182
Income (loss) before income taxes	1,036	13,991
(Provision) benefit from income taxes	(1,654)	(1,439)
Net income (loss)	(618)	12,552
Preferred stock dividends	(138)	(138)
Income (loss) applicable to common stockholders	(756)	12,414
Changes in comprehensive income (loss)	1,065	1,936
Comprehensive income (loss)	$ 447	$ 14,488
Equity in earnings (loss) of subsidiaries
Revenues	$ 131,017	$ 119,092
Cost of sales	74,320	73,965
Depreciation, depletion, amortization	25,875	25,254
General and administrative	$ 10,214	8,720
Gain on derivative contracts		5,792
Income (loss) before income taxes	$ 1,036	13,991
(Provision) benefit from income taxes	1,654	1,439
Net income (loss)	(618)	12,552
Preferred stock dividends	138	138
Income (loss) applicable to common stockholders	(756)	12,414
Comprehensive income (loss)	$ 447	$ 14,488