Supplemental Guarantor and Non-Guarantor Financial Information (Comprehensive Income/Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Supplemental guarantor and non-guarantor financial information
Net loss	$ (158,643)	$ (98,902)	$ (2,693,903)	$ (342,471)
Other comprehensive income (loss):
Change in pension and other postretirement benefit plans, net of tax	4,007	2,977	11,406	9,994
Change in unrealized gain on hedges, net of tax	0	0	0	1,679
Change in foreign currency translation adjustment	(13,922)	(21,672)	(10,827)	(8,244)
Total other comprehensive income (loss)	(9,915)	(18,695)	579	3,429
Total comprehensive loss	(168,558)	(117,597)	(2,693,324)	(339,042)
Reportable legal entities | Parent (Issuer)
Supplemental guarantor and non-guarantor financial information
Net loss	(158,643)	(98,902)	(2,693,903)	(342,471)
Other comprehensive income (loss):
Change in pension and other postretirement benefit plans, net of tax	4,007	2,977	11,406	9,994
Change in unrealized gain on hedges, net of tax				1,679
Change in foreign currency translation adjustment	(13,922)	(21,672)	(10,827)	(8,244)
Total other comprehensive income (loss)	(9,915)	(18,695)	579	3,429
Total comprehensive loss	(168,558)	(117,597)	(2,693,324)	(339,042)
Reportable legal entities | Guarantor Subsidiaries
Supplemental guarantor and non-guarantor financial information
Net loss	(87,928)	(25,408)	(209,705)	(36,763)
Other comprehensive income (loss):
Change in pension and other postretirement benefit plans, net of tax	3,846	2,963	10,946	9,954
Change in unrealized gain on hedges, net of tax				3
Change in foreign currency translation adjustment	0	0	0	0
Total other comprehensive income (loss)	3,846	2,963	10,946	9,957
Total comprehensive loss	(84,082)	(22,445)	(198,759)	(26,806)
Reportable legal entities | Non-Guarantor Subsidiaries
Supplemental guarantor and non-guarantor financial information
Net loss	(8,529)	1,184	(2,312,278)	(81,688)
Other comprehensive income (loss):
Change in pension and other postretirement benefit plans, net of tax	0	0	0	0
Change in unrealized gain on hedges, net of tax				0
Change in foreign currency translation adjustment	(13,922)	(21,672)	(10,827)	(8,244)
Total other comprehensive income (loss)	(13,922)	(21,672)	(10,827)	(8,244)
Total comprehensive loss	(22,451)	(20,488)	(2,323,105)	(89,932)
Eliminations
Supplemental guarantor and non-guarantor financial information
Net loss	96,457	24,224	2,521,983	118,451
Other comprehensive income (loss):
Change in pension and other postretirement benefit plans, net of tax	(3,846)	(2,963)	(10,946)	(9,954)
Change in unrealized gain on hedges, net of tax				(3)
Change in foreign currency translation adjustment	13,922	21,672	10,827	8,244
Total other comprehensive income (loss)	10,076	18,709	(119)	(1,713)
Total comprehensive loss	$ 106,533	$ 42,933	$ 2,521,864	$ 116,738