Shareholders' Equity - Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 2,757,422
Other comprehensive loss before reclassifications	(22,483)
Amounts reclassified from accumulated other comprehensive loss	(400)
Other comprehensive income (loss)	(22,883)	$ 42,057
Ending balance	2,730,447
Net Unrealized Gain (Loss) From Hedging Activities
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	3,557
Other comprehensive loss before reclassifications	(1,341)
Amounts reclassified from accumulated other comprehensive loss	(400)
Other comprehensive income (loss)	(1,741)
Ending balance	1,816
Foreign Currency Translation Adjustments
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(201,348)
Other comprehensive loss before reclassifications	(21,142)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive income (loss)	(21,142)
Ending balance	(222,490)
Total Accumulated Other Comprehensive Loss
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(197,791)
Ending balance	$ (220,674)