Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Interest rate swaps (effective portion)	$ (79,231,000)	$ (58,362,000)	$ (218,065,000)	$ (157,314,000)
Interest rate swaps (ineffective portion)	1,424,000	593,000	646,000	(16,000)
Loss before income tax benefit	(129,246,000)	(117,724,000)	(417,851,000)	(317,459,000)
Income tax benefit	30,344,000	17,000,000	75,380,000	132,799,000
Net income (loss)	(98,902,000)	(100,724,000)	(342,471,000)	(184,660,000)
Amortization of pension and postretirement benefit plans | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Prior service cost			1,104,000
Net actuarial loss			13,418,000
Settlement loss			1,627,000
Loss before income tax benefit			16,149,000
Income tax benefit			(6,155,000)
Net income (loss)			9,994,000
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Loss before income tax benefit			606,000
Income tax benefit			(230,000)
Net income (loss)			376,000
Interest rate swaps | Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Interest rate swaps (effective portion)			(1,095,000)
Interest rate swaps (ineffective portion)			$ 1,701,000