Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Costs, expenses and other operating
Asset impairment and mine closure costs		$ 85,500
Successor [Member]
Revenues	$ 600,975
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	461,410
Depreciation, depletion and amortization	31,921
Accretion on asset retirement obligations	7,623
Amortization of sales contracts, net	14,690
Change in fair value of coal derivatives and coal trading activities, net	854
Asset impairment and mine closure costs	0
Selling, general and administrative expenses	20,523
Other operating income, net	(2,310)
Total operating expenses	534,711
Income (loss) from operations	66,264
Interest expense, net
Interest expense	(9,425)
Interest and investment income	527
Interest expense, net	(8,898)
Income (loss) before nonoperating expenses	57,366
Nonoperating expenses
Net loss resulting from early retirement of debt and debt restructuring	(2,030)
Reorganization items, net	(2,828)
Nonoperating income (expense)	(4,858)
Income (loss) before income taxes	52,508
Provision for (benefit from) income taxes	840
Net income (loss)	$ 51,668
Net income (loss) per common share
Basic earnings (loss) per common share (in dollars per share)	$ 2.07
Diluted earnings (loss) per common share (in dollars per share)	$ 2.03
Weighted average shares outstanding
Basic weighted average shares outstanding (shares)	25,008
Diluted weighted average shares outstanding (shares)	25,408
Predecessor [Member]
Revenues		428,106
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)		411,010
Depreciation, depletion and amortization		63,699
Accretion on asset retirement obligations		8,306
Amortization of sales contracts, net		(833)
Change in fair value of coal derivatives and coal trading activities, net		1,210
Asset impairment and mine closure costs		85,520
Selling, general and administrative expenses		19,826
Other operating income, net		(2,220)
Total operating expenses		586,518
Income (loss) from operations		(158,412)
Interest expense, net
Interest expense		(44,451)
Interest and investment income		1,138
Interest expense, net		(43,313)
Income (loss) before nonoperating expenses		(201,725)
Nonoperating expenses
Net loss resulting from early retirement of debt and debt restructuring		(2,213)
Reorganization items, net		(3,875)
Nonoperating income (expense)		(6,088)
Income (loss) before income taxes		(207,813)
Provision for (benefit from) income taxes		(1,111)
Net income (loss)		$ (206,702)
Net income (loss) per common share
Basic earnings (loss) per common share (in dollars per share)		$ (9.71)
Diluted earnings (loss) per common share (in dollars per share)		$ (9.71)
Weighted average shares outstanding
Basic weighted average shares outstanding (shares)		21,293
Diluted weighted average shares outstanding (shares)		21,293