Note 14 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Income Statements, Captions [Line Items]
Revenues	$ 125,787	$ 76,450
Cost of sales	(77,741)	(36,825)
Depreciation, depletion, amortization	(25,803)	(14,007)
General and administrative	(7,941)	(6,939)
Exploration and pre-development	(4,569)	(11,284)
Gain/loss on derivative contracts	9,452	21,539
Other (expense) income	(3,761)	(10,425)
Income (loss) before income taxes	15,424	18,509
(Provision) benefit from income taxes	(3,783)	(7,415)
Net income (loss)	11,641	11,094
Changes in comprehensive income (loss)	1,350	(2,831)
Comprehensive income (loss)	12,991	8,263
Preferred stock dividends	(138)	(138)
Income (loss) applicable to common stockholders	11,503	10,956
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Equity in earnings of subsidiaries	(17,703)	1,073
Other (expense) income	(3,303)	1,950
Income (loss) before income taxes	(21,006)	3,023
(Provision) benefit from income taxes	(3,303)	(1,950)
Net income (loss)	(17,703)	1,073
Changes in comprehensive income (loss)	(1,373)	2,832
Comprehensive income (loss)	(19,076)	3,905
Income (loss) applicable to common stockholders	(17,703)	1,073
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	(19)	2,413
General and administrative	(4,630)	(3,472)
Exploration and pre-development	(44)	(164)
Gain/loss on derivative contracts	9,452	21,539
Equity in earnings of subsidiaries	17,703	(1,073)
Other (expense) income	(10,821)	(8,149)
Income (loss) before income taxes	11,641	11,094
Net income (loss)	11,641	11,094
Changes in comprehensive income (loss)	1,350	(2,831)
Comprehensive income (loss)	12,991	8,263
Preferred stock dividends	(138)	(138)
Income (loss) applicable to common stockholders	11,503	10,956
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	83,710	74,037
Cost of sales	(49,933)	(36,825)
Depreciation, depletion, amortization	(17,221)	(14,007)
General and administrative	(3,008)	(3,410)
Exploration and pre-development	(958)	(8,195)
Other (expense) income	408	(3,122)
Income (loss) before income taxes	12,998	8,478
(Provision) benefit from income taxes	(2,886)	(5,465)
Net income (loss)	10,112	3,013
Changes in comprehensive income (loss)	57	(427)
Comprehensive income (loss)	10,169	2,586
Income (loss) applicable to common stockholders	10,112	3,013
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	42,096
Cost of sales	(27,808)
Depreciation, depletion, amortization	(8,582)
General and administrative	(303)	(57)
Exploration and pre-development	(3,567)	(2,925)
Other (expense) income	9,955	(1,104)
Income (loss) before income taxes	11,791	(4,086)
(Provision) benefit from income taxes	(4,200)
Net income (loss)	7,591	(4,086)
Changes in comprehensive income (loss)	1,316	(2,405)
Comprehensive income (loss)	8,907	(6,491)
Income (loss) applicable to common stockholders	$ 7,591	$ (4,086)