Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Interest expense	$ 79,396	$ 52,618
Other loss	1,756	(105)
Loss before income tax benefit	128,139	115,483
Income tax benefit	(35,961)	(66,039)
Net loss	92,178	49,444
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
Income tax benefit	(230)
Net loss	376
Gains and losses on cash flow hedges | Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Interest rate swaps
Amounts reclassified out of each component of accumulated other comprehensive income (loss)
Interest expense	(1,095)
Other loss	1,701
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	368
Net actuarial loss	4,534
Settlement loss	784
Loss before income tax benefit	5,686
Income tax benefit	(2,167)
Net loss	$ 3,519