Changes in Accumulated Other Comprehensive (Loss) Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			$ 5,671	$ (134,516)
Other comprehensive income before reclassifications			(356,774)	118,297
Amounts reclassified from accumulated other comprehensive loss			10,214	(50,697)
Total other comprehensive (loss) income	(269,559)	73,160	(346,560)	67,600
Ending balance	(340,889)	(66,916)	(340,889)	(66,916)
Changes related to cash flow derivative hedges
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			43,324	(84,505)
Other comprehensive income before reclassifications			(330,103)	109,154
Amounts reclassified from accumulated other comprehensive loss			6,924	(52,639)
Total other comprehensive (loss) income			(323,179)	56,515
Ending balance	(279,855)	(27,990)	(279,855)	(27,990)
Changes in defined benefit plans
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(23,994)	(34,823)
Other comprehensive income before reclassifications			(6,829)	8,774
Amounts reclassified from accumulated other comprehensive loss			1,293	1,942
Total other comprehensive (loss) income			(5,536)	10,716
Ending balance	(29,530)	(24,107)	(29,530)	(24,107)
Foreign currency translation adjustments
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(13,659)	(15,188)
Other comprehensive income before reclassifications			(19,842)	369
Amounts reclassified from accumulated other comprehensive loss			1,997	0
Total other comprehensive (loss) income			(17,845)	369
Ending balance	$ (31,504)	$ (14,819)	$ (31,504)	$ (14,819)