Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Total Revenues	$ 285,563	$ 329,546	$ 378,351	$ 413,885	$ 471,996	$ 455,796	$ 441,496	$ 491,343	$ 1,407,345	$ 1,860,631	$ 2,399,895
Segment operating income (loss):
Operating loss	(105,602)	(54,833)	(99,439)	(47,062)	(17,711)	(59,081)	(30,553)	(63,620)	(306,936)	(170,965)	(1,013,126)
Interest expense, net									(295,903)	(221,583)	(132,997)
Gain on extinguishment of debt	32,800	3,400	11,400	(13,900)		(900)		6,000	33,673	(6,875)	(5,555)
Other income (loss), net									646	(1,418)	(13,081)
Loss from continuing operations before income tax benefit									(568,520)	(400,841)	(1,164,759)
Income tax expense (benefit)									(97,952)	(41,838)	(99,204)
Loss from continuing operations	(128,097)	(98,902)	(151,391)	(92,178)	(174,343)	(100,724)	(34,492)	(49,444)	(470,568)	(359,003)	(1,065,555)
Impairment and restructuring charges:
Impairment and restructuring charges									57,508	2,883	1,113,479
Depreciation and depletion:
Total depreciation and depletion									262,525	311,514	316,232
Capital expenditures:
Total capital expenditures									92,999	153,896	391,512
Identifiable assets by segment:
Total identifiable assets	5,386,129				5,590,860				5,386,129	5,590,860	5,768,420
Long-lived assets by country:
Total long-lived assets	4,303,098				4,542,554				4,303,098	4,542,554	4,697,688
Export sales
Export sales	285,563	329,546	378,351	413,885	471,996	455,796	441,496	491,343	1,407,345	1,860,631	2,399,895
Other postretirement benefits (income) expense									55,476	58,900	52,852
U.S.
Long-lived assets by country:
Total long-lived assets	876,079				998,763				876,079	998,763	1,034,992
Canada
Long-lived assets by country:
Total long-lived assets	3,007,732				3,092,483				3,007,732	3,092,483	3,203,227
U.K.
Long-lived assets by country:
Total long-lived assets	419,287				451,308				419,287	451,308	459,469
Foreign
Revenues:
Total Revenues									1,000,000	1,500,000	1,900,000
Export sales
Export sales									1,000,000	1,500,000	1,900,000
Sales | Foreign countries
Export sales
Threshold for sales to customers in foreign countries as a percentage of consolidated revenues (more than)									10.00%	10.00%	10.00%
Sales | Foreign countries | Germany
Export sales
Revenues from external customers as a percentage of consolidated revenues									9.60%	10.50%	9.70%
Sales | Foreign countries | Brazil
Export sales
Revenues from external customers as a percentage of consolidated revenues									10.70%	13.30%	10.70%
Sales | Foreign countries | Japan
Export sales
Revenues from external customers as a percentage of consolidated revenues									8.60%	13.20%	11.50%
U.S. Operations
Revenues:
Total Revenues									1,166,226	1,331,308	1,728,363
Segment operating income (loss):
Operating loss									(118,009)	58,371	188,696
Impairment and restructuring charges:
Impairment and restructuring charges									52,223	(7,763)	114,281
Depreciation and depletion:
Total depreciation and depletion									150,701	167,668	173,140
Capital expenditures:
Total capital expenditures									85,333	133,407	162,535
Identifiable assets by segment:
Total identifiable assets	1,122,850				1,265,255				1,122,850	1,265,255	1,603,745
Export sales
Export sales									1,166,226	1,331,308	1,728,363
Other postretirement benefits (income) expense									55,653	59,118	53,301
Canadian and U.K. Operations
Revenues:
Total Revenues									237,584	527,989	668,313
Segment operating income (loss):
Operating loss									(183,180)	(209,709)	(1,158,591)
Impairment and restructuring charges:
Impairment and restructuring charges									4,721	10,646	999,198
Depreciation and depletion:
Total depreciation and depletion									109,368	141,696	141,713
Capital expenditures:
Total capital expenditures									4,387	18,331	224,583
Identifiable assets by segment:
Total identifiable assets	3,538,073				3,687,925				3,538,073	3,687,925	3,728,817
Export sales
Export sales									237,584	527,989	668,313
Other
Revenues:
Total Revenues									3,535	1,334	3,219
Segment operating income (loss):
Operating loss									(5,747)	(19,627)	(43,231)
Impairment and restructuring charges:
Impairment and restructuring charges									564	0	0
Depreciation and depletion:
Total depreciation and depletion									2,456	2,150	1,379
Capital expenditures:
Total capital expenditures									3,279	2,158	4,394
Identifiable assets by segment:
Total identifiable assets	725,206				637,680				725,206	637,680	435,858
Export sales
Export sales									3,535	1,334	3,219
Other postretirement benefits (income) expense									$ (177)	$ (218)	$ (449)