Changes in Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	$ 3,692,188
Balance	3,690,046	$ 2,065,350
Tax benefit (expense) for unrealized net losses (gains) on available-for-sale securities before reclassifications		(389)
Tax benefit (expense) for unrealized net losses (gains) on cash flow hedges		18,895
Tax expense (benefit) related to pension and other postretirement benefit plans	90	(142)
Tax expense (benefit) for realized gains (losses) on the sale of available-for-sale securities for amounts reclassified from other comprehensive loss	760	(3)
Tax expense on realized gains on cash flow hedges	1,047
Foreign Currency Translation Adjustments
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	(353,346)	(501,277)
Amounts recognized in Other comprehensive loss	52,732	20,778
Net change	52,732	20,778
Balance	(300,614)	(480,499)
Pension and Other Postretirement Benefit Adjustments
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	(84,863)	(125,096)
Amounts reclassified from other comprehensive loss	(209)	279
Net change	(209)	279
Balance	(85,072)	(124,817)
Unrealized Net Gains on Available-for-Sale Securities
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	2,320	1,015
Amounts recognized in Other comprehensive loss		630
Amounts reclassified from other comprehensive loss	(2,320)	5
Net change	(2,320)	635
Balance	0	1,650
Unrealized Net Gains (Losses) on Cash Flow Hedges
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	51,019	85,007
Amounts recognized in Other comprehensive loss		(30,754)
Amounts reclassified from other comprehensive loss	(988)
Net change	(988)	(30,754)
Balance	50,031	54,253
Total Cumulative Other Comprehensive (Loss) Income
Changes in Net Other Comprehensive (Loss) Income [Roll Forward]
Balance	(384,870)	(540,351)
Amounts recognized in Other comprehensive loss	52,732	(9,346)
Amounts reclassified from other comprehensive loss	(3,517)	284
Net change	49,215	(9,062)
Balance	$ (335,655)	$ (549,413)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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

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

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