Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income and Other Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Rollforward
Beginning of Period			$ 1,861,054
Other comprehensive (loss) income:
Change in fair value of derivative instruments	$ (1,496)	$ 1,980	(9,101)	$ 4,183
End of Period	1,510,830		1,510,830
Foreign Currency Translation Adjustments
AOCI Rollforward
Beginning of Period	(253,243)	(209,653)	(264,691)	(103,989)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(82,886)	(22,790)	(71,438)	(128,454)
Change in fair value of derivative instruments	0	0	0	0
Total other comprehensive (loss) income	(82,886)	(22,790)	(71,438)	(128,454)
End of Period	(336,129)	(232,443)	(336,129)	(232,443)
Change in Fair Value of Derivative Instruments
AOCI Rollforward
Beginning of Period	(8,578)	2,203	(973)	0
Other comprehensive (loss) income:
Foreign currency translation adjustment	0	0	0	0
Change in fair value of derivative instruments	(1,496)	1,980	(9,101)	4,183
Total other comprehensive (loss) income	(1,496)	1,980	(9,101)	4,183
End of Period	(10,074)	4,183	(10,074)	4,183
Total
AOCI Rollforward
Beginning of Period	(261,821)	(207,450)	(265,664)	(103,989)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(82,886)	(22,790)	(71,438)	(128,454)
Change in fair value of derivative instruments	(1,496)	1,980	(9,101)	4,183
Total other comprehensive (loss) income	(84,382)	(20,810)	(80,539)	(124,271)
End of Period	$ (346,203)	$ (228,260)	$ (346,203)	$ (228,260)

Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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