Supplemental Guarantor and Non-Guarantor Financial Information (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues:
Sales	$ 489,609	$ 627,298
Miscellaneous income (loss)	1,734	4,265
Total revenues	491,343	631,563
Costs and expenses:
Cost of sales (exclusive of depreciation and depletion)	420,934	431,534
Depreciation and depletion	81,190	66,493
Selling, general and administrative	30,674	36,247
Postretirement benefits	14,725	13,213
Restructuring charges	7,440
Total costs and expenses	554,963	547,487
Operating income (loss)	(63,620)	84,076
Interest expense	(52,618)	(28,067)
Interest income	650	277
Other income (loss)	105	(6,993)
Income (loss) before income tax expense	(115,483)	49,293
Income tax expense (benefit)	(66,039)	8,677
Income (loss)	(49,444)	40,616
Net income (loss)	(49,444)	40,616
Parent (Issuer)
Revenues:
Miscellaneous income (loss)	553	675
Total revenues	553	675
Costs and expenses:
Depreciation and depletion	485	215
Selling, general and administrative	13,567	10,729
Postretirement benefits	(55)	(112)
Total costs and expenses	13,997	10,832
Operating income (loss)	(13,444)	(10,157)
Interest expense	(50,156)	(27,224)
Interest income	15	47
Other income (loss)		3,019
Income (loss) before income tax expense	(63,585)	(34,315)
Income tax expense (benefit)	(26,667)	(9,982)
Income (loss)	(36,918)	(24,333)
Equity in earnings (losses) of subsidiaries	(12,526)	64,949
Net income (loss)	(49,444)	40,616
Guarantor Subsidiaries
Revenues:
Sales	314,812	413,654
Miscellaneous income (loss)	2,190	4,071
Total revenues	317,002	417,725
Costs and expenses:
Cost of sales (exclusive of depreciation and depletion)	247,677	246,205
Depreciation and depletion	40,410	34,367
Selling, general and administrative	6,943	12,148
Postretirement benefits	14,780	13,325
Restructuring charges	116
Total costs and expenses	309,926	306,045
Operating income (loss)	7,076	111,680
Interest expense	(590)	(286)
Income (loss) before income tax expense	7,666	111,394
Income tax expense (benefit)	(3,396)	32,261
Income (loss)	11,062	79,133
Net income (loss)	11,062	79,133
Non-Guarantor Subsidiaries
Revenues:
Sales	174,797	213,644
Miscellaneous income (loss)	(1,009)	(481)
Total revenues	173,788	213,163
Costs and expenses:
Cost of sales (exclusive of depreciation and depletion)	173,257	185,329
Depreciation and depletion	40,295	31,911
Selling, general and administrative	10,164	13,370
Restructuring charges	7,324
Total costs and expenses	231,040	230,610
Operating income (loss)	(57,252)	(17,447)
Interest expense	(3,052)	(557)
Interest income	635	230
Other income (loss)	105	(10,012)
Income (loss) before income tax expense	(59,564)	(27,786)
Income tax expense (benefit)	(35,976)	(13,602)
Income (loss)	(23,588)	(14,184)
Net income (loss)	(23,588)	(14,184)
Eliminations
Costs and expenses:
Equity in earnings (losses) of subsidiaries	12,526	(64,949)
Net income (loss)	$ 12,526	$ (64,949)