Supplemental Guarantor and Non-Guarantor Financial Information (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Sales	$ 437,798	$ 668,605	$ 927,407	$ 1,295,903
Miscellaneous income (loss)	3,698	8,969	5,432	13,234
Total revenues	441,496	677,574	932,839	1,309,137
Cost and expenses:
Cost of sales (exclusive of depreciation and depletion)	367,616	486,084	788,550	917,618
Depreciation and depletion	68,320	74,459	149,510	140,952
Selling, general and administrative	27,129	35,845	57,803	72,092
Postretirement benefits	14,725	13,213	29,450	26,426
Restructuring and asset impairment	(5,741)		1,699
Total costs and expenses	472,049	609,601	1,027,012	1,157,088
Operating income (loss)	(30,553)	67,973	(94,173)	152,049
Interest expense	(53,129)	(31,104)	(105,747)	(59,171)
Interest income	144	341	794	618
Other loss, net	(714)	(5,919)	(609)	(12,912)
Income (loss) from continuing operations before income tax expense (benefit)	(84,252)	31,291	(199,735)	80,584
Income tax expense (benefit)	(49,760)	4,535	(115,799)	13,212
Income (loss) from continuing operations	(34,492)	26,756	(83,936)	67,372
Income from discontinued operations		5,180		5,180
Net income (loss)	(34,492)	31,936	(83,936)	72,552
Parent (Issuer)
Revenues:
Miscellaneous income (loss)	220	1,051	773	1,726
Total revenues	220	1,051	773	1,726
Cost and expenses:
Depreciation and depletion	511	2,235	996	3,933
Selling, general and administrative	11,684	12,941	25,251	22,187
Postretirement benefits	(55)	(113)	(110)	(225)
Total costs and expenses	12,140	15,063	26,137	25,895
Operating income (loss)	(11,920)	(14,012)	(25,364)	(24,169)
Interest expense	(49,414)	(29,448)	(99,570)	(56,672)
Interest income	28	61	43	108
Other loss, net		3,020		6,039
Income (loss) from continuing operations before income tax expense (benefit)	(61,306)	(40,379)	(124,891)	(74,694)
Income tax expense (benefit)	(22,108)	(13,583)	(48,775)	(23,565)
Income (loss) from continuing operations	(39,198)	(26,796)	(76,116)	(51,129)
Equity in earnings (losses) of subsidiaries	4,706	58,732	(7,820)	123,681
Net income (loss)	(34,492)	31,936	(83,936)	72,552
Guarantor Subsidiaries
Revenues:
Sales	299,198	435,395	614,010	849,049
Miscellaneous income (loss)	779	14,808	2,969	18,879
Total revenues	299,977	450,203	616,979	867,928
Cost and expenses:
Cost of sales (exclusive of depreciation and depletion)	211,314	271,977	458,991	518,182
Depreciation and depletion	33,673	34,296	74,083	68,122
Selling, general and administrative	7,144	10,818	14,087	23,507
Postretirement benefits	14,780	13,326	29,560	26,651
Restructuring and asset impairment	(9,063)		(8,947)
Total costs and expenses	257,848	330,417	567,774	636,462
Operating income (loss)	42,129	119,786	49,205	231,466
Interest expense	(590)	(254)		(540)
Interest income	116	2	116	2
Income (loss) from continuing operations before income tax expense (benefit)	41,655	119,534	49,321	230,928
Income tax expense (benefit)	8,533	33,220	5,137	65,481
Income (loss) from continuing operations	33,122	86,314	44,184	165,447
Net income (loss)	33,122	86,314	44,184	165,447
Non-Guarantor Subsidiaries
Revenues:
Sales	138,600	233,210	313,397	446,854
Miscellaneous income (loss)	2,699	(6,890)	1,690	(7,371)
Total revenues	141,299	226,320	315,087	439,483
Cost and expenses:
Cost of sales (exclusive of depreciation and depletion)	156,302	214,107	329,559	399,436
Depreciation and depletion	34,136	37,928	74,431	68,897
Selling, general and administrative	8,301	12,086	18,465	26,398
Restructuring and asset impairment	3,322		10,646
Total costs and expenses	202,061	264,121	433,101	494,731
Operating income (loss)	(60,762)	(37,801)	(118,014)	(55,248)
Interest expense	(3,125)	(1,402)	(6,177)	(1,959)
Interest income		278	635	508
Other loss, net	(714)	(8,939)	(609)	(18,951)
Income (loss) from continuing operations before income tax expense (benefit)	(64,601)	(47,864)	(124,165)	(75,650)
Income tax expense (benefit)	(36,185)	(15,102)	(72,161)	(28,704)
Income (loss) from continuing operations	(28,416)	(32,762)	(52,004)	(46,946)
Income from discontinued operations		5,180		5,180
Net income (loss)	(28,416)	(27,582)	(52,004)	(41,766)
Eliminations
Cost and expenses:
Equity in earnings (losses) of subsidiaries	(4,706)	(58,732)	7,820	(123,681)
Net income (loss)	$ (4,706)	$ (58,732)	$ 7,820	$ (123,681)