Changes in Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Changes in accumulated other comprehensive loss by component
Total other comprehensive income	$ 34,620	$ 234,144	$ 103,685	$ 389,590
Changes related to cash flow derivative hedges
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(250,355)	(820,850)
Other comprehensive income (loss) before reclassifications			106,505	230,341
Amounts reclassified from accumulated other comprehensive loss			4,071	151,319
Total other comprehensive income			110,576	381,660
Ending balance	(139,779)	(439,190)	(139,779)	(439,190)
Changes in defined benefit plans
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(33,666)	(28,083)
Other comprehensive income (loss) before reclassifications			5,863	(7,130)
Amounts reclassified from accumulated other comprehensive loss			1,086	850
Total other comprehensive income			6,949	(6,280)
Ending balance	(26,717)	(34,363)	(26,717)	(34,363)
Foreign currency translation adjustments
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(50,244)	(67,551)
Other comprehensive income (loss) before reclassifications			(13,840)	14,210
Amounts reclassified from accumulated other comprehensive loss			0	0
Total other comprehensive income			(13,840)	14,210
Ending balance	(64,084)	(53,341)	(64,084)	(53,341)
Accumulated other comprehensive loss
Changes in accumulated other comprehensive loss by component
Accumulated comprehensive loss at beginning of the year			(334,265)	(916,484)
Other comprehensive income (loss) before reclassifications			98,528	237,421
Amounts reclassified from accumulated other comprehensive loss			5,157	152,169
Total other comprehensive income			103,685	389,590
Ending balance	$ (230,580)	$ (526,894)	$ (230,580)	$ (526,894)

Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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