Summary of Significant Accounting Policies (Schedule of Change in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 5,783,487	$ 4,860,863	$ 4,422,813
Ending balance	7,067,009	5,783,487	4,860,863
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(825,354)	(788,652)	(428,505)
Current period other comprehensive income (loss) before reclassifications	277,427	(36,702)	(360,147)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Ending balance	(547,927)	(825,354)	(788,652)
Pensions and post-retirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(7,673)	(4,916)	(816)
Current period other comprehensive income (loss) before reclassifications	(2,927)	(2,757)	(4,100)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Ending balance	(10,600)	(7,673)	(4,916)
AOCI including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(833,027)	(793,568)	(429,321)
Current period other comprehensive income (loss) before reclassifications	274,500	(39,459)	(364,247)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Ending balance	$ (558,527)	$ (833,027)	$ (793,568)