Shareholders' Equity - Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			$ 2,713,097	$ 1,877,339
Effect of adoption of new accounting standards					$ (298)
Other comprehensive income (loss) before reclassifications			(38,660)
Amounts reclassified from accumulated other comprehensive loss			19
Other comprehensive income (loss)	$ (11,238)	$ 51,262	(38,641)	158,346
Ending balance	3,027,317	$ 2,469,297	3,027,317	$ 2,469,297
Net Unrealized Gain From Hedging Activities
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			1,535
Other comprehensive income (loss) before reclassifications			5,285
Amounts reclassified from accumulated other comprehensive loss			19
Other comprehensive income (loss)			5,304
Ending balance	6,839		6,839
Net Unrealized Gain From Hedging Activities | ASU No. 2017-12
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Effect of adoption of new accounting standards					53
Foreign Currency Translation Adjustments
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(142,360)
Other comprehensive income (loss) before reclassifications			(43,945)
Amounts reclassified from accumulated other comprehensive loss			0
Other comprehensive income (loss)			(43,945)
Ending balance	(186,305)		(186,305)
Foreign Currency Translation Adjustments | ASU No. 2017-12
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Effect of adoption of new accounting standards					0
Total Accumulated Other Comprehensive Loss
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(140,825)
Ending balance	$ (179,466)		(179,466)
Total Accumulated Other Comprehensive Loss | ASU No. 2017-12
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Effect of adoption of new accounting standards					$ 53
Previously Reported | Net Unrealized Gain From Hedging Activities
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			1,482
Previously Reported | Foreign Currency Translation Adjustments
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(142,360)
Previously Reported | Total Accumulated Other Comprehensive Loss
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			$ (140,878)