Supplemental Guarantor and Non-Guarantor Financial Information (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental guarantor and non-guarantor financial information
Net loss	$ (470,568)	$ (359,003)	$ (1,060,375)
Other comprehensive income (loss), net of tax:
Change in pension and other postretirement benefit plans (net of tax: $1,102, $60,013, and $23,330, respectively)	(33,819)	100,892	(40,501)
Change in unrealized gain on hedges, net of tax	1,679	2,524	(3,416)
Change in foreign currency translation adjustment	(23,650)	6,073	1,774
Change in unrealized gain (loss) on investments, net of tax	0	(897)	769
Total other comprehensive income (loss), net of tax	(55,790)	108,592	(41,374)
Total comprehensive loss	(526,358)us-gaap_ComprehensiveIncomeNetOfTax	(250,411)us-gaap_ComprehensiveIncomeNetOfTax	(1,101,749)us-gaap_ComprehensiveIncomeNetOfTax
Parent (Issuer)
Supplemental guarantor and non-guarantor financial information
Net loss	(470,568)	(359,003)	(1,060,375)
Other comprehensive income (loss), net of tax:
Change in pension and other postretirement benefit plans (net of tax: $1,102, $60,013, and $23,330, respectively)	(33,819)	100,892	(40,501)
Change in unrealized gain on hedges, net of tax	1,679	2,524	(3,416)
Change in foreign currency translation adjustment	(23,650)	6,073	1,774
Change in unrealized gain (loss) on investments, net of tax		(897)	769
Total other comprehensive income (loss), net of tax	(55,790)	108,592	(41,374)
Total comprehensive loss	(526,358)	(250,411)	(1,101,749)
Guarantor Subsidiaries
Supplemental guarantor and non-guarantor financial information
Net loss	(109,641)	(15,990)	169,207
Other comprehensive income (loss), net of tax:
Change in pension and other postretirement benefit plans (net of tax: $1,102, $60,013, and $23,330, respectively)	(30,275)	91,501	(90,876)
Change in unrealized gain on hedges, net of tax	3	58	95
Change in foreign currency translation adjustment	0	0	0
Change in unrealized gain (loss) on investments, net of tax		0	0
Total other comprehensive income (loss), net of tax	(30,272)	91,559	(90,781)
Total comprehensive loss	(139,913)	75,569	78,426
Non-Guarantor Subsidiaries
Supplemental guarantor and non-guarantor financial information
Net loss	(88,170)	(129,278)	(1,130,741)
Other comprehensive income (loss), net of tax:
Change in pension and other postretirement benefit plans (net of tax: $1,102, $60,013, and $23,330, respectively)	0	0	0
Change in unrealized gain on hedges, net of tax	0	0	(2,533)
Change in foreign currency translation adjustment	(23,650)	6,073	1,774
Change in unrealized gain (loss) on investments, net of tax		(897)	769
Total other comprehensive income (loss), net of tax	(23,650)	5,176	10
Total comprehensive loss	(111,820)	(124,102)	(1,130,731)
Eliminations
Supplemental guarantor and non-guarantor financial information
Net loss	197,811	145,268	961,534
Other comprehensive income (loss), net of tax:
Change in pension and other postretirement benefit plans (net of tax: $1,102, $60,013, and $23,330, respectively)	30,275	(91,501)	90,876
Change in unrealized gain on hedges, net of tax	(3)	(58)	2,438
Change in foreign currency translation adjustment	23,650	(6,073)	(1,774)
Change in unrealized gain (loss) on investments, net of tax		897	(769)
Total other comprehensive income (loss), net of tax	53,922	(96,735)	90,771
Total comprehensive loss	$ 251,733	$ 48,533	$ 1,052,305

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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