Supplemental Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 644,462	$ 713,776	$ 1,321,467	$ 1,449,747
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	566,252	622,137	1,128,574	1,308,451
Depreciation, depletion and amortization	97,372	102,464	202,246	206,887
Amortization of acquired sales contracts, net	(1,644)	(3,239)	(5,034)	(6,935)
Change in fair value of coal derivatives and coal trading activities, net	1,211	(2,992)	2,431	(2,078)
Asset impairment and mine closure costs	19,146	1,512	19,146	1,512
Selling, general and administrative expenses	24,268	29,931	46,873	59,067
Other operating (income) expense, net	7,403	(232)	16,489	(8,230)
Total operating expenses	714,008	749,581	1,410,725	1,558,674
Income (loss) from investment in subsidiaries	0	0	0	0
Loss from operations	(69,546)	(35,805)	(89,258)	(108,927)
Interest expense, net
Interest expense	(99,574)	(97,960)	(198,826)	(194,431)
Interest and investment income	962	2,036	3,335	3,879
Interest expense, net	(98,612)	(95,924)	(195,491)	(190,552)
Expenses related to debt restructuring	(4,016)	0	(4,016)	0
Loss before income taxes	(172,174)	(131,729)	(288,765)	(299,479)
Provision for (benefit from) income taxes	(4,071)	(34,869)	(7,467)	(78,480)
Net loss	(168,103)	(96,860)	(281,298)	(220,999)
Total comprehensive income (loss)	(167,887)	(98,437)	(277,478)	(225,206)
Parent/Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	5,908	3,547	13,378	6,937
Depreciation, depletion and amortization	1,013	1,346	2,073	2,818
Amortization of acquired sales contracts, net	0	0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0	0	0	0
Asset impairment and mine closure costs	1,225	1,512	1,225	1,512
Selling, general and administrative expenses	17,166	21,729	32,605	41,673
Other operating (income) expense, net	(138)	(1,883)	3,562	(290)
Total operating expenses	25,174	26,251	52,843	52,650
Income (loss) from investment in subsidiaries	(30,462)	2,502	(9,413)	(32,844)
Loss from operations	(55,636)	(23,749)	(62,256)	(85,494)
Interest expense, net
Interest expense	(119,231)	(116,084)	(237,286)	(229,739)
Interest and investment income	6,675	8,125	14,747	15,726
Interest expense, net	(112,556)	(107,959)	(222,539)	(214,013)
Expenses related to debt restructuring	(4,016)		(4,016)
Loss before income taxes	(172,208)	(131,708)	(288,811)	(299,507)
Provision for (benefit from) income taxes	(4,105)	(34,848)	(7,513)	(78,508)
Net loss	(168,103)	(96,860)	(281,298)	(220,999)
Total comprehensive income (loss)	(167,887)	(98,437)	(277,478)	(225,206)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	644,462	713,776	1,321,467	1,449,747
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	561,191	619,470	1,116,877	1,303,246
Depreciation, depletion and amortization	96,359	101,109	200,171	204,051
Amortization of acquired sales contracts, net	(1,644)	(3,239)	(5,034)	(6,935)
Change in fair value of coal derivatives and coal trading activities, net	1,211	(2,992)	2,431	(2,078)
Asset impairment and mine closure costs	17,921	0	17,921	0
Selling, general and administrative expenses	6,270	7,250	12,514	15,115
Other operating (income) expense, net	7,483	1,554	12,760	(7,929)
Total operating expenses	688,791	723,152	1,357,640	1,505,470
Income (loss) from investment in subsidiaries	0	0	0	0
Loss from operations	(44,329)	(9,376)	(36,173)	(55,723)
Interest expense, net
Interest expense	(6,576)	(6,565)	(13,340)	(12,890)
Interest and investment income	20,256	18,341	40,030	35,993
Interest expense, net	13,680	11,776	26,690	23,103
Expenses related to debt restructuring	0		0
Loss before income taxes	(30,649)	2,400	(9,483)	(32,620)
Provision for (benefit from) income taxes	0	0	0	0
Net loss	(30,649)	2,400	(9,483)	(32,620)
Total comprehensive income (loss)	(30,811)	1,647	(6,405)	(34,779)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	0	0	0	0
Depreciation, depletion and amortization	0	9	2	18
Amortization of acquired sales contracts, net	0	0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0	0	0	0
Asset impairment and mine closure costs	0	0	0	0
Selling, general and administrative expenses	1,325	1,489	2,773	3,292
Other operating (income) expense, net	(1,282)	(1,320)	(2,533)	(2,756)
Total operating expenses	43	178	242	554
Income (loss) from investment in subsidiaries	0	0	0	0
Loss from operations	(43)	(178)	(242)	(554)
Interest expense, net
Interest expense	(1,127)	(1,092)	(2,402)	(2,142)
Interest and investment income	1,391	1,351	2,760	2,500
Interest expense, net	264	259	358	358
Expenses related to debt restructuring	0		0
Loss before income taxes	221	81	116	(196)
Provision for (benefit from) income taxes	34	(21)	46	28
Net loss	187	102	70	(224)
Total comprehensive income (loss)	187	102	70	(224)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs, expenses and other
Cost of sales (exclusive of items shown separately below)	(847)	(880)	(1,681)	(1,732)
Depreciation, depletion and amortization	0	0	0	0
Amortization of acquired sales contracts, net	0	0	0	0
Change in fair value of coal derivatives and coal trading activities, net	0	0	0	0
Asset impairment and mine closure costs	0	0	0	0
Selling, general and administrative expenses	(493)	(537)	(1,019)	(1,013)
Other operating (income) expense, net	1,340	1,417	2,700	2,745
Total operating expenses	0	0	0	0
Income (loss) from investment in subsidiaries	30,462	(2,502)	9,413	32,844
Loss from operations	30,462	(2,502)	9,413	32,844
Interest expense, net
Interest expense	27,360	25,781	54,202	50,340
Interest and investment income	(27,360)	(25,781)	(54,202)	(50,340)
Interest expense, net	0	0	0	0
Expenses related to debt restructuring	0		0
Loss before income taxes	30,462	(2,502)	9,413	32,844
Provision for (benefit from) income taxes	0	0	0	0
Net loss	30,462	(2,502)	9,413	32,844
Total comprehensive income (loss)	$ 30,624	$ (1,749)	$ 6,335	$ 35,003