Note 16 - Guarantor Subsidiaries - Condensed Consolidating Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues	$ 645,957	$ 443,567	$ 500,781
Cost of sales	(338,983)	(293,567)	(304,446)
Depreciation, depletion, and amortization	(115,468)	(111,489)	(111,134)
General and administrative	(45,040)	(34,201)	(31,538)
Exploration and pre-development	(17,857)	(21,958)	(19,667)
Gain on derivative contracts	4,423	8,252	9,134
Acquisition costs	(2,695)	(2,162)
Equity in earnings of subsidiaries
Other (expense) income	(33,362)	(19,100)	(30,546)
Income (loss) before income taxes	96,975	(30,658)	12,584
Income tax (provision) benefit	(27,428)	(56,310)	5,240
Net income	69,547	(86,968)	17,824
Series B Preferred Stock dividends declared	(552)	(552)	(552)
Net income (loss) applicable to common shares	68,995	(87,520)	17,272
Change, net of tax	(1,971)	(600)	(5,732)
Comprehensive (loss) income	67,576	(87,568)	12,092
Cost of sales	(454,451)	(405,056)	(304,446)
Closed operations		(2,162)
Consolidation, Eliminations [Member]
Revenues
Cost of sales
Depreciation, depletion, and amortization
General and administrative
Exploration and pre-development
Gain on derivative contracts
Acquisition costs
Equity in earnings of subsidiaries	(94,878)	(49,565)	(72,407)
Other (expense) income	(19,344)	54,188	(16,295)
Income (loss) before income taxes	(114,222)	4,623	(88,702)
Income tax (provision) benefit	19,344	(54,188)	16,295
Net income	(94,878)	(49,565)	(72,407)
Series B Preferred Stock dividends declared
Net income (loss) applicable to common shares	(94,878)	(49,565)	(72,407)
Change, net of tax	(2,665)	208	177
Comprehensive (loss) income	(97,543)	(49,357)	(72,230)
Cost of sales
Closed operations
Parent Company [Member] | Reportable Legal Entities [Member]
Revenues	(14,237)	6,194	1,473
Cost of sales
Depreciation, depletion, and amortization
General and administrative	(23,262)	(17,920)	(17,667)
Exploration and pre-development	(304)	(627)	(252)
Gain on derivative contracts	4,423	8,252	9,134
Acquisition costs	(2,607)
Equity in earnings of subsidiaries	94,878	49,565	72,407
Other (expense) income	10,656	(131,915)	(47,271)
Income (loss) before income taxes	69,547	(86,968)	17,824
Income tax (provision) benefit
Net income	69,547	(86,968)	17,824
Series B Preferred Stock dividends declared	(552)	(552)	(552)
Net income (loss) applicable to common shares	68,995	(87,520)	17,272
Change, net of tax	(1,971)	(600)	(5,732)
Comprehensive (loss) income	67,576	(87,568)	12,092
Cost of sales
Closed operations		(517)
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Revenues	369,162	287,941	333,460
Cost of sales	(203,133)
Depreciation, depletion, and amortization	(64,374)	(67,815)	(72,937)
General and administrative	(20,425)	(14,508)	(12,694)
Exploration and pre-development	(6,640)	(7,177)	(7,088)
Gain on derivative contracts
Acquisition costs	(34)
Equity in earnings of subsidiaries
Other (expense) income	11,400	22,537	29,753
Income (loss) before income taxes	85,956	26,650	75,894
Income tax (provision) benefit	(25,334)	(7,251)	(10,565)
Net income	60,622	19,399	65,329
Series B Preferred Stock dividends declared
Net income (loss) applicable to common shares	60,622	19,399	65,329
Change, net of tax	8	(467)	(1,329)
Comprehensive (loss) income	60,630	18,932	64,000
Cost of sales		(192,683)	(194,600)
Closed operations		(1,645)
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Revenues	291,032	149,432	165,848
Cost of sales	(135,850)
Depreciation, depletion, and amortization	(51,094)	(43,674)	(38,197)
General and administrative	(1,353)	(1,773)	(1,177)
Exploration and pre-development	(10,913)	(14,154)	(12,327)
Gain on derivative contracts
Acquisition costs	(54)
Equity in earnings of subsidiaries
Other (expense) income	(36,074)	36,090	3,267
Income (loss) before income taxes	55,694	25,037	7,568
Income tax (provision) benefit	(21,438)	5,129	(490)
Net income	34,256	30,166	7,078
Series B Preferred Stock dividends declared
Net income (loss) applicable to common shares	34,256	30,166	7,078
Change, net of tax	2,657	259	1,152
Comprehensive (loss) income	$ 36,913	30,425	8,230
Cost of sales		(100,884)	(109,846)
Closed operations